Faulty Signal. Permanent Fault

Faulty signal. Permanent fault

Checking vehicle speed sensor signal








- Ignition off.
- Remedy control module and vehicle speed sensor (VSS) connectors for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Reinstall components, reconnect connectors etc.
- Raise car so that drive wheels rotate freely.
- Engine idling.
- Gear selector in position D.
- Read off the transmission speed signal.
Check that speed increases with engine speed (RPM). If speed is updated, the cause of the fault was loose connections in the control module or vehicle speed sensor (VSS) connector.

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





Does speed increase with engine speed (RPM)?

Yes - FAULT FOUND

No - Checking cables and sensors

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Checking cables and sensors
Check power supply cable between vehicle speed sensor (VSS) connector #1 (control module side) and control module #A57 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Hint: With control module connected and ignition on, the voltage between vehicle speed sensor connector #1 and ground (breakout box #53) should be approximately 8-12 V.

Check signal cable between vehicle speed sensor (VSS) connector #2 (control module side) and control module #A39 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.

Other information:
- To connect the breakout box, see Connecting breakout box, Transmission control module (TCM) Connecting Breakout Box, Transmission Control Module (TCM).
- To check/replace speed sensor, see Replacing vehicle speed sensor (VSS) .
- For information about signals, see Signal specification, Transmission control module (TCM) Signal Description AW50-42.









Was a fault detected?

Yes - Verification

No - No Fault Found

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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 FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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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 - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Checking vehicle speed sensor signal

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