Signal Missing. Permanent Fault

Signal missing. Permanent fault

Checking the vehicle speed sensor (VSS) signal




- Ignition off
- Check the transmission control module (TCM) and speed sensor connectors. Check for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Remedy if necessary
- Raise the car so that the drive wheels are clear of the ground
- Start the engine. Allow the engine to idle
- Move the gear selector to position D so that the drive wheels begin to rotate
- Read off the transmission speed.
Depress the accelerator pedal (AP) and check that the speed is updated.

Note! Ensure that the wheels are not rotating when the gear selector is moved.

Note! Diagnostic trouble codes (DTCs) may be stored in the ABS system when the rear wheels are stationary and the front wheels rotate. Erase any diagnostic trouble codes (DTCs) stored in the ABS system after fault-tracing.

If the speed is updated, the cause of the fault was probably contact resistance or oxidation in the control module or vehicle speed sensor (VSS) connectors.





Was the speed updated?

Yes - No Fault Found

No - Checking wiring and sensors

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Checking wiring and sensors




- Ignition off
- Connect the breakout box.
Check the power supply cable between transmission control module (TCM) terminal #A57 (#A57) and transmission output speed sensor connector terminal #A4. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the signal cable between transmission control module (TCM) terminal #A39 (#A39) and transmission output speed sensor connector terminal #A3. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Hint: With the control module connected, the ignition on and a voltmeter connected between transmission output speed sensor connector terminals #A3 and #A4 (control module side), the voltage must be approximately 1-3 V below Ubat.

Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting the breakout box, B5244T5, B5254T2 Connecting the Breakout Box
- To disconnect the transmission control module (TCM), see Transmission control module (TCM), replacing, B5244T5, AW55-50/51SN, B5254T2, AW55-50/51SN, B5254T2, AW50/51 AWD Service and Repair
- To check or replace the transmission output speed sensor, see Input speed sensor/output speed sensor, replacing Input Speed Sensor/Output Speed Sensor, Replacing
- For information about signals, see Signal description. Transmission control module (TCM), AW50/51 AWD, AW55-50/51SN Signal Description. Transmission Control Module (TCM).










Continue - Verification

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Verification




Verification

Hint: After carrying out the repair, check that the fault has been remedied.








- Ignition off.
- Reinstall connectors, components etc.
- Raise car so that drive wheels are unimpeded.
- Start the engine and let it idle.
- Shift gear selector to position D so that the drive wheels begin to rotate.
- Read off the transmission speed.
Check that speed is updated

Note! When the rear wheels are stationary and the front wheels rotate, diagnostic trouble codes (DTCs) can be stored in the ABS system. Erase any diagnostic trouble codes (DTCs) stored in the ABS system after fault-tracing.

Note! Ensure that the wheels are not rotating when the gear selector is moved.





Was speed updated?

Yes - VERIFIED

No - VERIFICATION FAILEDPAPER

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VERIFIED - Fault Found

VERIFICATION FAILED - Fault-tracing information

PAPER - No Fault Found

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Fault-tracing information




Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the vehicle speed sensor (VSS) signal

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