Electronic transmissions

Terminology:
Abbreviations
PCM=powertrain control module
TCC=torque converter
TPS=throttle position sensor
ECT=engine coolant temperature
VSS=vehicle speed sensor
PSA=pressure switch assembly
TTS=trans temp sensor

Shift solenoids
which solenoids are "on" when this vehicle is shifted into drive and it starts out in 1st gear?
2nd and OD

which solenoids are on when this vehicle automatically shifts into second gear?
OD and LR

which solenoids are on when this vehicle automatically shifts into 3rd gear?
LR and 2nd

which solenoids are on when this vehicle automatically shifts into forth gear?
LR and UD

ABS (anti-lock braking system for RHD)

Wiring diagram practice

using the wiring diagram identify the wheel speed sensor's wire colours:
-front right= White + Black
-front left= Green + Red
-rear left= Pink + Blue
-rear right= Broen + yellow

The reason for the braded wire on the ABS wheel sensor is to stop interferance and it sheilds the wires from frequency.

identify and list all the fuses that are used by the ABS circuit:
-ignition fuse
-warning light fuse
-stop light fuse
-ABS fuse

Earths for the ABS control unit and ABS motor, wires and pins :
-pin-10  White/black
-pin-7  White/Black

identify which solenoids control each wheel cylinder, wire colours and pin numbers:
-Front right: Pin-6a        wire colour-red white
-Front left wheel:  pin numbers-3B,7B          wire colour- Blue/red and Blue/white
-rear left wheel:  Pin numbers-1B and 5B      wire colour-Brown/red and Brown/white

In four cases stae when the ABS motor will be working?
-when the wheels lock up
-when the wheels spin abnormally fast
-when the brake is suddenly applied
-when under or over steer happens

ABS demonstrators
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 i could tell that the sensors were magnetic inducer type sensors
How it works:
A passing magnet induces a current through the windings and it has a magnet that increases the magnetic field in the windings.

next i grabed a set up ABS module and hooked up a occiloscope and recorded a waveform for the front right sensor...

The waveform for the front left and the back left were the same and the front right and back right were both the same but both right sensors had a higher peak voltage than the left ones.

with the wheel speed sensors spinning, measure AC volts with a multi-meter and record the voltages (RMS):

left front  3.593V

left rear   2.696V

right front  4.473V

right rear   5.14V

this is not an accurate way to find problems compared to and oscilloscope

An oscilloscope is better to find problems with the wheel speed sensors than a multi-meter because an oscilloscope measures and records waveforms which can show peak voltages and frequencies whereas a muti-meter cannot.

Honda Multiplexing Board

1: Using the wiring diagram identify the plugs/pins and wire colours for the communication lines between the Nodes.
-Block B pin 1 (drivers) to block B pin 9 (passengers), pink wire
-Block A pin 15 (door) to block A pin 2 (drivers), brown wire

2: Using the wiring diagram identify the plugs/pins and wire colours for the Earths and voltage supply lines between the nodes.

Earths:  All wires are black
-from door Node, Block A pin 12 to G401 Block A pin 19 to G581=LHD, G581=RHD
-From drivers node, B11 to G501, A14 to G401, B22 to G501, A8 ro G401
Inputs:
-To door node, pink wire A1 to drivers-white/black wire to A1
-pink wire A12, fuse relay box socket (no wire) A24 to passengers node fuse box relay socket A24, yellow wire A22.

Ask your instructor to create a fault in the unit, describe how this fault is affecting the normal operation of this system.
-The passenger, back left, back right window acuators are not working and the central locking actuator isnt working.
By using the wiring diagram i diagnosed the fault and came to a conclusion that the communication wire is split.

After reading the manual put the system in to test modde 1 and record any faults, how many times the node beeps.
we got 1 short beep which means the drivers unit is not able to receive signals from the door unit.

to test the fault you have to do a voltage drop test not a resistance check because you cannot unplug the wires and cannot injuce a current because it can damage components.
when i did the voltage drop test i got a value of 0.2V DC across the brown communication wire which means there is a split in the wire because the wire is bi-directional so both ends are trying to send signals.

The door unit has no inputs to the drivers unit because i discovered in question 4 that the brown communication line was split or open circuited which is stoping the door node from sending signals to the driverside node.

using the wiring diagram from the back of the manual describe what tests you would carry out now and what results you would expect. Note wire colours pin/block numbers.
Do a voltage drop test between A15 and A2 and it should be 0V if it was good but in our case there was a volt drop of 0.2V because at pin A15 it was 8.7V and at A15 it was 8.5V. This volt drop indicates there is a break in between A15 and A2, another test you could do is a continuity test but you cant do this while the drivers node is plugged in so what you have to do is unplug the whole drivers node and unplug the plug at the door node.

CAN - Multiplexing Worksheet

1.1  locate the Range Rover or other suitable vehicle with easily accessible CAN system twisted wires. Which vehicle do you have?
   Range Rover, 2005

1.2  locate a twisted wire pair. Describe where the wires are located: Next to the ABS module in the engine compartment.

Record the waveforms:

This waveform is the one of the L CAN fast CAN ABS which was a yellow wire with a brown stripe. Time Div. 5 micro seconds Voltage Div. 1V                                                                                             

This waveform is the one of the H CAN also on the fast CAN because it is the H CAN on the ABS and is a yellow wire with a black stripe

What is Aliasing?

"Jagged,stairset effect on curved or diagonal lines that are reproduced in low resolution as on a computer printout or display"-from Dictionary.com

The waveforms i captured from the ABS CAN in the above images are not Aliasing because the both waveforms are clear and correct.

the main voltage for the L CAN is 2.5v

     "          "             "           "          2.5v

The voltage that is pulled down on the L CAN is 1.4V

The voltage that is pulled up on the H CAN is 3.5V

1.9 Observe the signals from the H and L wires with a voltmeter. Compare it with AC volts and DC volts setting. Which setting would tell you if the signal is switching?.

          H CAN       L CAN

DC      2.36V        2.62V

AC     0.1mV        0.1mV

The DC setting would tell you if the signal is switching because it only measures positive voltage signals whereas AC reads both Negative and Postive voltages and in this case we are only dealing with positive voltages therefor the DC setting is adequate.

Scan tool observation

The vehicle i used to plug the scan tool into was a 2005 Range Rover and the scan tool i was using was an Autoboss.

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

-control unit version

-fault codes

-actual values (All select)

-acual values (manual select)

-actuators

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

High speed:

-Air bags

-instrument cluster

-ABS

Low speed:

-lights

-wiper

-washer fluid

-central locking

-window acuators

-mirror

-air cond

The system which goes to "sleep" is the CAN system after a short time, the vltage you see when its awake is 2.5-2.6v DC and when its asleep you see 0.2mV DC and the wire in which this voltage chage occurs is the L CAN wire (yellow wit brown stripe).

The amp drain when the CAN system is asleep is about 40mA and the System takes around 2 seconds to go to sleep and by simply unlocking a door will wake up the system.

Controlled Area Network board

CAN Board

Each pattern which is sent through the H and L-CAN is "infomation" which is a series of "0's" and "1's" which are digital signals sent as voltage levels, Above a set voltage it counts a "1" and below a set voltage it counts a "0" and a internal clock records the voltage at certain intervals.
By using the dual-trace function on a oscillloscope I captured the full pattern of the H-can and the L-can and identified which wire was the H-Can and the L-Can.                                                         NOTE# CH-A=1.00V CH-B=1.00V   M=25 micro seconds

This pattern is the original start and stop pattern, you can't see on the screen the channels but the top line is channel A and the bottom line is channel B. Channel A is the H-CAN, I know this because on the channel A the pattern starts on 3.5V and switches down to about 2.5V which means its the High CAN because it starts at 3.5V and switches down to 2.5V. Channel B is the L-CAN (Low CAN) because it does the complete opposite to the H-CAN ie. instead of starting at 3.5V and switching down it starts at 0.5V and switches down to about 2.5V which indicates that this is the L-CAN.                                                                          

  Relationship between the two patterns and their base voltages (what volts when not switched) 

-The H-CAN and L-CAN are opposites.

-Base voltages are 2.5V for both CANS.

-H-CAN is switching up.

-L-CAN is switching down.

-Both switch at thw same time.

Next i was asked to capture the following inputs on the oscilloscope and identify where it changes in relation to the original start stop pattern.

-right indicator

-left indicator

-rear wiper

-stoplights

-fuel pump

-reverse lights

NOTE# the divisions are the same as the original pattern (CH-A=1.00V  CH-B=1.00V and M=25 micro seconds) 

Right indicator

left indicator

Stop lights

Reverse lights

As you can see all these patterns are completely different to the original pattern, this is because each code has to be different to difine what needs to be switched on e.g. various sets of lights etc. this code is the amount of zeros and ones within each pattern which this amount changes depending on what needs to be switched on.

Using the wiring diagram and CAN board identify the input/output pins, wire colours, relay or transistor for the right hand indicator.
R indicator= 7-6
input voltage (pin 7)- RA4/tock I (6) then output signal from RB2/can tx and Rb3/canRx to pins 1 (TxD) and 2 (RxD) then the output pins 7CanH and 6CanL to Ic4 (communicator) and CanL to can receiver IC5 and then the output pins TxD to TXCAN/TXRXCAN and RXD to RXCAN/NC and from the outputs GP4/REF and then to OPTOC coupling which switches the transistor which responds to light from the LED which then switces another transistor on which then finally switches the right hand indicator on

General lab scope patterns

Task: gather waveforms using a general lab scope from various sensors, First back probe the likely wire for the sensor and attach the lab scobe to get a pattern on the screen.

The 1st pattern i got was the injectors (picture to the right). to do so i back probed the likely input wire to injector one. The 1st horizontal line on the injector pattern is the 12 volt supply to the injector and then at the point where it drops to 0v is when the injector is being switched on by being earth triggered through the ECU. From the point where it was earthed to the point where the line shoots up is the injection time (how long the injector is open for) and the part that shoots up to about 60 volts is due to the coils within the injector discharing, this is also known as back EMF and then the pattern evens back out to the 12v supply until the next earth trigger then this pattern is repeated.

The next pattern i recorded was of the O2 sensor. I back probed the likely output wire of the O2 sensor.

This pattern shows the voltage change that the O2 sensor puts out as the oxygen levels within the exaust manifold changes. This uneven line is due to the change in revs because as i reved the engine silmiltaneosly the voltage would spike up because more oxygen was present. Because this engine i was on was not it closed loop the O2 sensor was not cycling which means that it wasnt switching between running rich and lean to burn the fuel evenly and with less harmful gases.

The next one is of the MAP sensor. The MAP sensor was locate within the ECU on the engine i was on but i could measure it on the sircuit board on the engine stand. The A point on the pattern is the 0 volt line which when the throttle is fully closed is about 0.02 volts because alot of vacuum is present within the intake manifold and as i opened the throttle gradually the voltage output from the MAP would go up which is the slope on the lab scope and then as i slowly let the throttle out and the slope goes down back to 0.02. This is important because the output from the MAP determines the amount of fuel the injectors inject and if the ECU were to receive an incorrect reading from the MAP it would effect the operation of the engine.

The pattern to the right is the waveform of an ECT sensor and what it shows is how the voltage decreases as the Engine coolant temerature increases. When the engine coolant is cold the voltage output from the ECT is between 2.2v and 2.5v and as you can see on the lab scope it decreases gradually as the coolant heats up and eventually when it gets to operating temp it will read about 0.5v. This reading from the ECT is important because when the engine is colt it needs more fuel to get to operating temp so the ECU needs to know the temp of the coolant which it can calculate from the voltage the ECT puts out, and as the coolant heats up it no needs to inject the added fuel.

This next one is the the TPS (throttle position sensor). The TPS on the engine was a 3 wire potentiometer type and i back probed the likely output wire to the ECU. On the scope just above the "A" is a flat line until it starts to slope up, this flat line is about 0.5v and the throttle is completely closed and as i open the throttle to halfway the voltage output goes up to about 2.2v and you can see this on the scope where the line first slopes up. As i open the throttle right up the voltage then increases to about 4.5v. all these different voltage outputs lets the ECU know what position the throttle is at and affects the total operation of the engine.



Flash codes

Task:
       -Find an engine that you have the workshop manual with the correct procedure and codes to diagnose the flash codes.
       -have your tutor create a fault in the efi system
       -using the workshop manual  follow the procedure to extract the codes, explain briefly what is the procedure.
The engine i chose to extract the flash codes from was a 4a-fe toyota 4 cyl motor.During this test the engine is off but the ignition is on.
the procedure to extracting the codes: -locate diognostic plug and open flap
                                                          -bridge pins "TE1" and "E1" with a fused jumper wire
                                                          -the engine light will display on dash
if a fault is present the engine light will flash as long as the pins te1 and e1 are bridged, there will be a series of flashes and to read these yo record the number of flashes. The fisrst set of flashes is the "10's" of the code i.e if the engine light were to flash 3 times it would mean it is 30. After the 1st set there will be a pause and another set of flashes will happen and this is the "1's" of the code i.e. if the engine light flashed 1 time it would mean the 2nd digit of the overall code would be 1, now you add the 10's and 1's together to get the code which in this case its 31 and i can now go to the manual and look up what that code is and it is the vaccum sensor (MAP sensor).

The tutor put 3 faults in and by following the procedure above i diagnosed the codes and got the ones in the chart below.

Code number	System affected	Condition described
22	Water temp sircuit	Unplugged
31	Vaccum sensor (map sensor)	Unplugged
41	Throttle position	unplugged

Other conditions that could cause these systems to be affected could be that the plug is corroded, wires to the sensor could be incorectly probed and split causing high resistance in that particular circuit. to repair the above faults all i had to do was plug all of them back in but if the plugs were to be corroded or the wires were exposed i would replace immediatly.
Once the faults are repaired the fault codes were still present and needed to be cleared, to do this all i had to do was turn the ignition off and take the jumper wire out and then rechecked that the codes had gone i turned the ignition on and started the engine and the the engine light switched off soon after the engine was started and the engine ran fine.
In result of these faults the engine would not run right because the ECU was not getting any signals from the sensors affected E.g. the water temp sensor was unpluged which meant the ECU was receiving 0.0 volts which told the ECU to run lean because it thinks the engine is really hot.