On Vehicle Testing

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ABS wheel speed sensors:


Q. On the vehicle that you have been assigned does it use analogue or digital wheel sensors?
A. Digital

Q. how did you conclude that the wheel sensors were analogue or digital?
A. Checked with oscilloscope

Measure the air gap for each wheel sensor.
State the air gap and visual condition of each wheel sensor

Front Right: 0.022 in (inches)
Front Left: 0.024 in
Rear Right: 0.022 in
Rear Left: 0.024 in

Oscilloscope pattern:

Q. Is this pattern an analogue or digital pattern?
A. Analogue

Using a scan tool go to the ABS live data screen and note all the sensors, data and what it is telling you?

1, It has three stages solenoid: hold, up and down
Up: It builds the pressure
Down: Releases the pressure
Hold: Holds the pressure

2, Motor runs when we give the command through scan tool
3, When it is on, the relay clicks
4, On turning off,m it clicks again

Electronic Transmission and Scan Tools


Abbreviations
PCM= Powertrain Control Module
TCC= Torque Converter Clutch
TPS= Throttle Position Sensor
ECT= Engine Coolant Temperature Sensor
VSS= Vehicle Speed Sensor
RSA= Transmission Range Fluid Pressure Switch Assembly
TTS= Transmission Temperature Sensor

Block Diagram:

Wiring Diagram

                                               (Holden: Diagnostic Trouble Codes)

Shift Solenoids:


Q. Which solenoids are "on" when this vehicle is shifted into drive and starts out in first gear?
A. 1-2 and 2-3

Q. Which solenoids are "on" when this vehicle automatically shifts into second gear?
A. 2-3

Q. Which solenoids are "on" when this vehicle automatically shifts into third gear?
A. None

Q. Which solenoids are "on" when this vehicle automatically shifts into fourth gear?
A. 1-2

Shift Solenoid Malfunction: Describe what would happen if none of the solenoids came "on". Would the vehicle drive? What gear would it be in? How fast could the vehicle go? could it have the power to climb hill?

A. Yes, the vehicle would drive. It would drive in third gear. It can go fast as the vehicle normally run in third gear but it couldn't have that much power to climb the hill.

Codes: 
Code: 21
This code is for high Voltage of TPS. It shows that the signal voltage stays 4.9 V for about two seconds at engine idling. Loose connection at earth can cause this code
Code: 14
This code is for low voltage signal to PCM by ECT sensor. The short circuiting of the signal wire can cause this code.

Diagnosis:


First problem testing: We can do the voltage drop test for that with help of a multi-meter. we can check the wiring manually if there is any loose connection in the circuit. we can check the resistance of the circuit to earth with help of a muti-meter. Oscilloscope is the another tool for checking TPS activity by examining the waveform on the screen.

Second problem testing: Checking the resistance of the circuit and voltage drop test with multi-meter can help in finding the problem in the circuit.