CAN – Multiplexing Worksheet

1.0 CAN Waveform on Oscilloscope

1.1 Locate the Range Rover or other suitable vehicle with easily accessible CAN system twisted wires. Which vehicle do you have? (Year, make and model) _2003 land rover ___________________________________________________

1.2 Locate a twisted wire pair. Describe where the wires are located: by the ABS TCS ECU ____________________________________________________

____________________________________________________

1.3 Record the waveform of one of the wires below: (Make sure your time is small enough so you don’t have “aliasing”.)

I

Colour of wire: yel br ……………………………………

Time per division: …200ms………………………………

Voltage per division: ………1v……………………..

1.4 Record the waveform of the other wire in the twisted pair.

Colour of wire: yel black……………………………………

Time per division: …200ms………………………………

Voltage per division: ………1v……………………..

1.5 What is aliasing? Describe it.

Aliasing is the distornion of readings on a osilloscope ______________________________________________________________

______________________________________________________________

______________________________________________________________

1.6 How do you know these waveforms are not “aliasing”?

Because the is no distortion and they are clear and easy to read

______________________________________________________________

______________________________________________________________

______________________________________________________________

1.7 In the 1.3 waveform above, what is the main voltage on the line?

2.3v …………

What is the other voltage on the line, when the voltage is pulled up or down to “talk” ?

……….

1.8 In the 1.4 waveform above, what is the main voltage on the line?

…0.25v…….

What is the voltage on the line, when the voltage is pulled up or down to “talk”?

……….

1.9 Observe the signals in 1.3 and 1.4 above with a voltmeter. Compare it with DC volts or AC volts setting. Which setting would tell you if the signal is switching. Explain:

______________________________________________________________

a DC waveform would tell us if the componet was switchin by flatlining when not switching and then jump when switching then flat lining the top of the jump till the switch is turned off.

______________________________________________________________

______________________________________________________________

2.0 Scan Tool Observations

2.1 Find a vehicle that will show CAN system operation on a scan tool (such as the Range Rover.

Which vehicle are you using? Land rover 2003……………………………………………..…

Which scan tool are you using? Autoboss star……………………………………………..

2.2 What different functions are available on the scan tool to examine the CAN system?

_print, portrait, landscape, demo, quickscan and manual scan __________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

___________________________________________________

2.3 List the different systems that are controlled by CAN? (note which are high speed and which are low speed)

ABS, ESP, TCS high speed_________________________________

EHC electronic ride level_________________________________

EDC electronic damper control_________________________________

MRS multiple restraint systems_________________________________

_________________________________

_________________________________

_________________________________

_________________________________

_________________________________

_________________________________

3.0 Wiring Diagram Exercise

3.1 Locate a wiring diagram for a CAN system (hopefully one you can investigate or work on.) i've got a MOPAR 1973 man CAN wiring diagram

3.2 Describe the type of wiring diagram this is?

Both central and engine CAN diagram

3.3 Show the high speed system parts of the diagram.

Red = high speed systems of the diagram

4. Show the low speed parts of the system on the diagram.

   Black = the low speed systems

   3.5..Show the location of a “Gateway” on the diagram.

Blue = gateway

6. Show where the system could be “divided” to aide in diagnosis.

Green is the division line

7. Describe how this is helpful in diagnosis:

   it limits what you are testing with the scan tool and limits down the fault finding proc

______________________________________________________________

______________________________________________________________

______________________________________________________________

3.8 Locate a system that goes to “sleep” after a short time. What is it?

Pink is the sleeping system.

______________________________________________________________

3.9 What voltage do you see when it is “awake”? …12 volts………………………

What voltage do you see when it is “asleep”? ……0……………………

On what wire do you see this voltage change? ………the switch wire C538 …………………

3.10 Amp Drain:

Measure the amp drain at the battery when the system is asleep ……..

Measure the amp drain at the battery when the system is awake: ……..

How long did it take the system to go to sleep? …………

What made the system “wake up”? ……………………………………….

CAN

CAN – Multiplexing Worksheet
1.0 CAN Waveform on Oscilloscope
1.1 Locate the Range Rover or other suitable vehicle with easily accessible CAN system twisted wires. Which vehicle do you have? (Year, make and model) _2003 land rover

Colour of wire: yel br ……………………………………

Time per division: …200ms……………………………… V

oltage per division: ………1v…………………….. ___________________________________________________
1.2 Locate a twisted wire pair. Describe where the wires are located: by the ABS TCS ECU ____________________________________________________
____________________________________________________
1.3 Record the waveform of one of the wires below: (Make sure your time is small enough so you don’t have “aliasing”.)
I

Colour of wire: yel br ……………………………………
Time per division: …200ms………………………………
Voltage per division: ………1v……………………..
1.4 Record the waveform of the other wire in the twisted pair.

Colour of wire: yel black……………………………………
Time per division: …200ms………………………………
Voltage per division: ………1v……………………..
1.5 What is aliasing? Describe it.
Aliasing is the distornion of readings on a osilloscope ______________________________________________________________
______________________________________________________________
______________________________________________________________
1.6 How do you know these waveforms are not “aliasing”?
Because the is no distortion and they are clear and easy to read
______________________________________________________________
______________________________________________________________
______________________________________________________________
1.7 In the 1.3 waveform above, what is the main voltage on the line?
2.3v …………
What is the other voltage on the line, when the voltage is pulled up or down to “talk” ?
……….
1.8 In the 1.4 waveform above, what is the main voltage on the line?
…0.25v…….
What is the voltage on the line, when the voltage is pulled up or down to “talk”?
……….
1.9 Observe the signals in 1.3 and 1.4 above with a voltmeter. Compare it with DC volts or AC volts setting. Which setting would tell you if the signal is switching. Explain:
______________________________________________________________
a DC waveform would tell us if the componet was switchin by flatlining when not switching and then jump when switching then flat lining the top of the jump till the switch is turned off.
______________________________________________________________
______________________________________________________________
2.0 Scan Tool Observations
2.1 Find a vehicle that will show CAN system operation on a scan tool (such as the Range Rover.
Which vehicle are you using? Land rover 2003……………………………………………..…
Which scan tool are you using? Autoboss star……………………………………………..
2.2 What different functions are available on the scan tool to examine the CAN system?
_print, portrait, landscape, demo, quickscan and manual scan __________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
___________________________________________________
2.3 List the different systems that are controlled by CAN? (note which are high speed and which are low speed)
ABS, ESP, TCS high speed_________________________________
EHC electronic ride level_________________________________
EDC electronic damper control_________________________________
MRS multiple restraint systems_________________________________
_________________________________
_________________________________
_________________________________
_________________________________
_________________________________
_________________________________
3.0 Wiring Diagram Exercise
3.1 Locate a wiring diagram for a CAN system (hopefully one you can investigate or work on.) i've got a MOPAR 1973 man CAN wiring diagram
3.2 Describe the type of wiring diagram this is?
Both central and engine CAN diagram
3.3 Show the high speed system parts of the diagram.
Red = high speed systems of the diagram
Show the low speed parts of the system on the diagram.
Black = the low speed systems
3.5..Show the location of a “Gateway” on the diagram.
Blue = gateway
Show where the system could be “divided” to aide in diagnosis.
Green is the division line
Describe how this is helpful in diagnosis:
it limits what you are testing with the scan tool and limits down the fault finding proc
______________________________________________________________
______________________________________________________________
______________________________________________________________
3.8 Locate a system that goes to “sleep” after a short time. What is it?
Pink is the sleeping system.
______________________________________________________________
3.9 What voltage do you see when it is “awake”? …12 volts………………………
What voltage do you see when it is “asleep”? ……0……………………
On what wire do you see this voltage change? ………the switch wire C538 …………………
3.10 Amp Drain:
Measure the amp drain at the battery when the system is asleep ……..
Measure the amp drain at the battery when the system is awake: ……..
How long did it take the system to go to sleep? …………
What made the system “wake up”? ……………………………………….

abs 2nd half

On vehicle testing:
LIFTING & SUPPORTING VEHICLES
Student Name …………………………………………………
Date …………………………….
To safely lift and support a motor vehicle on a flat surface
Vehicle opel……………………………. Model vectra…………………………………
Ensure the floor surface is clean and flat
Apply the parking brake; slacken wheel nuts of wheels to be removed
Identify a safe vehicle chassis member to lift the vehicle using the jack
Lift the jack until it is touching the chassis member
Release the parking brake to allow the vehicle to roll while lifting
\recheck the location of the jack before lifting the wheels off the ground
Locate axle stands in a safe position on solid vehicle member
Have your tutor check before lowering the jack
Lower the jack slowly until the vehicle is supported by the stands
Tutor check …………………………………………………..
To safely lower the vehicle to the ground after being supported on axle stands:
Ensure all wheels and nuts are located before removing vehicle stands
Lower the vehicle gently to the floor
Apply parking brake
Torque and check wheel nut tightness
Have your tutor check the vehicle
20
On-Car Exercises
On the vehicle that you have been assigned identify the following components to your tutor:
Wheel speed sensor
ABS control unit
ABS modulator
ABS pump motor
Parking brake switch
Brake master cylinder
Brake fluid level switch (if fitted)
RPM sensor
Foot brake switch
Brake booster
Main ABS control unit fuse
Instructor OK? _X__
21
ABS Wheel Speed Sensors
On the vehicle that you have been assigned does it use analogue or digital wheel sensors?
_________analog wheel sensors
______________________________________________________________________
_______________________________________________________________________________
How did you conclude that the wheel sensors were analogue or digital?
__________________________________________________________________________because the scan tool gave us a analog wave form_____
_______________________________________________________________________________
_______________________________________________________________________________
Tutor signature ……………………….
Measure the air gap for each wheel sensor.
State the air gap and visual condition of each wheel sensor
Front Right
_____________0.152mm________________________________________________________________________
_____________________________________________________________________________________
Front Left
____________________0.152_________________________________________________________________
_____________________________________________________________________________________
Rear Right
_________________________cant get to the gap____________________________________________________________
_____________________________________________________________________________________
Rear Left
___________________________cant get to the gap__________________________________________________________
_____________________________________________________________________________________
22
Using an oscilloscope connect it to a wheel sensor and record the pattern shown, If the sensor is a
Analogue sensor then just connect then probe and spin the wheel. If the sensor is digital you will
need to have the ignition on before you turn the wheels. (show scale)
Is this pattern an analogue or digital pattern?
___analogue____________________________________________________________________________
_______________________________________________________________________________
Using the frequency scale on a multi-meter. Turn the wheel at proximally the same speed as in the
above test. Note the frequency and compare it to the graph you drew above.
Frequency__125.30 Hz _____________________________________________________________________
Observations
_______________________________________________________________________________
_______________________________________________________________________________
________________________________________________________________________________________
________________________________________________________________________________________
23
Using a Scan Tool
Using a scan tool go to the ABS live data screen and note all the sensors, data and what it is telling
you
……LF Wheel speed sensor
RF wheel speed sensor ………………………………………………………………………………………..
………LR wheel speed sensor …………………………………………………………………………………………
RR wheel speed sensor. ………………………………………………………………………………………………
…Brake switch ………………………………………………………………………………………………..
3.FL hold sol. command ………………………………………………………………………………………………
…FL Hold sol. Feedback …………………………………………………………………………………………………
4.FL release sol command and feedback …………………………………………………………………………………………………
…FR hold sol. Command and feedback ………………………………………………………………………………………………….
5.FR release sol command and feedback …………………………………………………………………………………………………
…RL Release sol feedback and command ………………………………………………………………………………………………….
6.RL hold sol command and feedback …………………………………………………………………………………………………..
……………………………………………………………………………………………………..
7. RR hold sol command and feedback …………………………………………………………………………………………………...
…………………………………………………………………………………………………........
8 RR .Release sol command and feedback …………………………………………………………………………………………………...
……………………………………………………………………………………………………….
9. …………………………………………………………………………………………………...
……………………………………………………………………………………………………...
24
Using the scan tool on the vehicle you have been assigned to. Go to the actuator test screen.
Note below what component you have tested and what happened when you tested that component
and the test results.
1. ……………………………………………………………………………………………..
…………………………………………………………………………………………………
2. ……………………………………………………………………………………………..
…RF valve went on off on off ………………………………………………………………………………………………
3.LR out went on off ………………………………………………………………………………………………
…………………………………………………………………………………………………..
4. ………………………………………………………………………………………………
……………………………………………………………

4825

1
Student Name: _______________________
Antilock Braking Systems Lab Workbook (4825)
Off-car Exercises
Think about ABS Repair:
Misconceptions, The ABS system should be simple and robust, with the Module/ECU/Controller
almost never giving any trouble.
Below are some possible causes for damaging an ECU.
Spiked by careless welding, i.e. MIG welding without disconnecting the battery. True/False
___t___
Enclosure seal damaged and with obvious sign of water ingress.
True/False __t____
Obvious signs of mechanical damage to the enclosure.
True/False __t____
Often the ECU will be misdiagnosed as faulty, usually because the technician is inexperienced infault finding.
Faults are much more likely to be with connections or sensors.
True/False ___t___
Discuss how these ECU issues should be incorporated into diagnostic practices to test an ABS system:
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
2
ABS Wiring and Operation
Lets review the ABS system to remind ourselves what components are included and how they
should work.
T EC F R
Assembl
R F
Diagnostic
s
Warning
lamp
Front
1
2
3
4
6
7
5
Fill in the blanks with the name of the part:
1 = disc rotor 6 = wheel cylinder
2 = rear wheel sensor 7 = brake booster
3 = pulse ring
4 = ABS/TCS hydraulic modulator
5 = master cylinder



Wiring Diagram Practice
There are a number of components in the ABS systems that are also used for fuel injection. These
are mostly speed sensors e.g. wheel speed and engine speed.
Using the wiring diagram in the workshop manuals identify the wheel speed sensors and list their
wire colours for each sensor
Front right Black
Front left Red
Rear left Pink
Rear right Brown
On the ABS wheel sensor what is the reason for the braded wire?
So that if the wire comes loose and rubs on the tire or rotor it does not rip or fray

_________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Identify and list all the fuses that are used by the ABS circuit
F.L main

F.L alter

F.L ABS

AJ11

ECU-IG

GAUGE

STOP

DOME____________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Identify the earths for the ABS control unit and ABS motor their wire colours what pins numbers
The motor is on pins 1a and 2a and is earthed off 2a and the colour is white with a black stripe

The control unit is on pin 4a and 3a and is earthed through PKB on pin 10b of the ABS ecu then gets earthed at B1
_____________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
On the wiring diagram for the ABS actuator, identify which solenoids control which wheel cylinder.
Then note the wire colours and pin numbers
Front Right Wheel
Pin number 2b and 6b
Wire colour rw and rg_________________
Front Left Wheel
Pin number 7b and 3b_________________
Wire colour lr and lw_________________
Rear Left Wheel
Pin number_3b and 7b_______________
Wire colour_brw,brr________________
Rear Right Wheel
Pin number 8b and 4b ________________
Wire colour gb, gy________________
Using the picture on the next page as a guide, which of the following gives the correct condition of
the inlet and outlet solenoids valves under normal braking?
A: ____ Inlet valve Open Outlet valve Open
B: √ Inlet valve Open Outlet valve Closed
C: ____ Inlet valve Closed Outlet valve Open
D: ____ Inlet valve Closed Outlet valve Closed
Using the picture on the next page as a guide, which of the following gives the correct condition of
The inlet and outlet solenoids valves when the ABS is operating to reduce wheel brake pressure?

A: ____ Inlet valve Open Outlet valve Open
B:____ Inlet valve Open Outlet valve Closed
C: √ Inlet valve Closed Outlet valve Open
D: ____ Inlet valve Closed Outlet valve Closed
7
Using the picture as a guide, which of the following gives the correct condition of the inlet and outlet
solenoids valves when the ABS is operating to hold brake pressure?
A:____ Inlet valve Open Outlet valve Open
B:____ Inlet valve Open Outlet valve Close
C:____ Inlet valve Closed Outlet valve Open
D: √ Inlet valve Closed Outlet valve Closed
Using the picture as a guide, which of the following gives the correct condition of the inlet and outlet
solenoids valves when the ABS is operating to increase wheel brake pressure?
A:____ Inlet valve Open Outlet valve Open
B: √ Inlet valve Open Outlet valve Closed
C:____ Inlet valve Closed Outlet valve Open
D:____ Inlet valve Closed Outlet valve Closed
8
In the four cases above state when the ABS motor will be working?
The ABS motor will be working in the holding pressure and releasing pressure and the increasing pressure state because this is when the pump is working which needs the motor to work.
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
There are three main types of wheel sensors on modern vehicles. One sends an analogue signal
Using an inductive pick up, the others send a digital signal using ether hall effect or magnetoresistant
encoder.
On the graph below draw a digital signal that switches 5 volts every 2 seconds.
Mark volt and time scales on graph that will show the signal well.
9





































On the graph below draw an analogue signal with a frequency of 0.5 Hz and a maximum of +3
volts. Mark volt and time scales on graph that will show the signal well.

10
ABS Demonstrators
Locate the wiring diagram for your demonstrator vehicle. Find the ABS wheel speed sensor pinout
connections to the ECU on the wiring diagram and the demonstrator. Record which ECU wires
go to which wheel speed sensors:
Left front ECU Pin # ____4____ and ___5_____
Left rear ECU Pin # ____7____ and ____9____
Right front ECU Pin # ___11_____ and ___21_____
Right rear ECU Pin # ____24____ and ___26_____
By looking at the wiring diagram, what type of speed sensor is this?
___hall effect
____________________________________________________________________________
Describe how it works:
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Locate an oscilloscope. Turn it on and set it up to be fully operational. What oscilloscope are you
using? Digitech QC1922_________________________
Record a waveform for each wheel speed sensor in the boxes below. Note voltage per division
and time per division for each. Please don’t keep the ABS units on very long because it drains the
batteries.
11
Which wheel is this? ___LF_____
Which wheel is this? ___RF_____
12
Which wheel is this? _____LR___
13
Are all the waveforms exactly the same? Yes ____ No X__. Discuss what are the differences,
and what can cause these differences between the waveforms:
_______________________________________________________________________________
_the voltage reading and thew amplitude of the wave form______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
With the wheel speed sensors spinning, measure AC volts with a multi-meter and record here:
Left front ________3.5
Left rear ________2.5
Right front ________4.4
Right rear ________5.2
Can a multi-meter be as accurate in finding problems with the wheel speed sensors as an
oscilloscope? Yes ____ No __X__
Discuss what the oscilloscope could find that the multi-meter can not find and why:
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
14
ABS Relays
Record the name of the relay or switch that powers up the ABS ECU: (look at the wiring diagram)
___K38_________________
Record the name of the relay or switch that powers up the ABS pump: (look at the wiring diagram)
______K100_____________
Record the name of the relay or switch that sends power to the ABS HCU solenoids: (look at the
wiring diagram)
______K39_____________
Relay wire identification: (Consult the wiring diagram)
What is the ECU pin number for the wire that brings in the power to the ABS ECU?
________pin 1___________
What is the ECU pin number, or other number, for the wire that controls the relay for the ABS
ECU?
______pin 27_____________
What is the pin number for the wire that brings in the power to the ABS Pump?
________pin 30___________
What is the pin number, or other number, for the wire that controls the relay for the ABS Pump?
_____pin 28______________
15
Relay waveform: Capture a waveform that shows both the control circuit change when it turns on
the relay, and the power switching on to power something in the ABS system. (Use an oscilloscope time= I on, 3.2 off, .2 per division. Volts= 0-12
with two channels to capture this pattern. You may have to carefully set the trigger to capture this.)
Record the waveform below with the time and volts per division, and explain what you are
measuring.











Explain with arrows what is happening in the waveform above.
_______________________________________________________________________________
_______________________________________________________________________________
_________________________________I______________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
16
ABS Pump Relay waveform: Capture a waveform that shows both the control circuit change
when it turns on the relay, and the power switching on to power the ABS Pump. (Use a oscilloscope
with two channels to capture this pattern. You may have to carefully set the trigger to capture this.)
Record the waveform below with the time and volts per division.



Explain with arrows what is happening in the waveform above.
Time=.2 per division 1.5on 6off volts= 0-12
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
17
Observe what happens during the ABS Self Test when you first turn the key on. Watch the warning
lights, and observe power at the wires with the oscilloscope. Then discuss what is happening in the
ABS system during the Self Test.
______________________________________________________________________tcs stays on for 4 sec abs does not not turn off_________

time= .2 on 6x.2 off

______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
Create a fault in the system by slowing down a wheel speed sensor or safely shorting out an
inductive wheel speed sensor while you are applying the brakes. (Don’t’ short out a Hall Effect or
Magneto-Resistive sensor) As you are applying the brakes, notice if the ABS pumps turns on,
solenoids turn on, or if the hydraulic pressure changes in one of the brake circuits and shows up on
the pressure gauge. Discuss what is happening below:
______________________________________________________________________abs dosent work_________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________

Catch an oscilloscope pattern when an ABS solenoid has actuated. What is the pin and name of
the solenoid?pin 1 and earth ___________ How did you do it?
I put wires to pin 1 and earth_______________________________________________________________________________
_____2.4 off and 2.5 on at .2 per division and 12 volts_____________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
_______________________________________________________________________________
18
Draw the oscilloscope pattern below. Note the time and voltage per division.