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Home >> Volvo >> 1998 >> S90 L6-2.9L VIN 96 B6304S >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> AT / DTC Codes (Transmission Control Module) >> AT-232 Speedometer Signal >> Signal Missing

Signal Missing





Checking The Speedometer
An alternative to the following method is to drive the car on the road.

- Ignition OFF.
- Raise car so that rear wheels rotate freely.
- Engine idling.
- Move the gear selector to position D so the rear wheels begin to rotate.
- Check speedometer is operating correctly.

NOTE:
- When the front wheels are stationary and the rear wheels rotate diagnostic trouble codes (DTCs) may can be stored in the ABS system. Erase any diagnostic trouble codes stored in the ABS system after fault-tracing.
- Ensure that the rear wheels are not rotating when the gear shift lever is moved.

- Is the speedometer working?

Yes:
- Proceed to: Checking The Speedometer Signal To The Transmission Control Module section below.

No:
- Proceed to: Checking For A Short-circuit section below.





Checking For A Short-circuit
- Fault-trace the combined instrument panel and vehicle speed sensor (VSS).

NOTE: The speedometer can malfunction if there has been a short-circuit to supply voltage in signal cable between the automatic transmission control module (TCM) and combined instrument panel. Check this before replacing combined instrument panel.

- Proceed to: Verification section below.





Checking The Speedometer Signal To The Transmission Control Module
An alternative to the following method is to drive the car on the road.

- Ignition OFF.
- Rear wheels raised.
- Engine idling.
- Go into scrolling values.
- Read off speed.
- Move the gear selector to position D so the rear wheels begin to rotate.
- Check that road speed corresponds to the speedometer reading.

NOTE:
- When the front wheels are stationary and the rear wheels rotate diagnostic trouble codes may can be stored in the ABS system. Erase any diagnostic trouble codes stored in the ABS system after fault-tracing.
- Ensure that the rear wheels are not rotating when the gear shift lever is moved.

- Does road speed correspond to speedometer reading?

Yes:
- Proceed to: Intermittent Fault section below.

No:
- Proceed to: Connecting The Test Box section below.





Connecting The Test Box
- Ignition OFF.
- Connect the test box and check ground terminals.
- Proceed to: Checking Signal section below.





Checking Signal
- Ignition OFF.
- Connect transmission control module.
- Raise car so that rear wheels can rotate freely.
- Move gear selector to position N.
- Ignition ON.
- Connect a voltmeter between # 8 and # 15 on the test box. Block one rear wheel and spin the other rapidly.

NOTE: When the front wheels are stationary and the rear wheels rotate diagnostic trouble codes may can be stored in the ABS system. Erase any diagnostic trouble codes stored in the ABS system after fault-tracing.

- The voltmeter should read 4-7 Volts.

If reading is OK:
- Proceed to: Checking Speedometer Ground section below.

If value is lower:
- Proceed to: Checking Signal Cable Resistance To Ground section below.

If value is higher:
- Proceed to: Checking For A Short-circuit section below.





Checking For A Short-circuit
- Check cable between combined instrument panel terminal C:12 and transmission control module # 8 for a short-circuit to supply voltage.
- Proceed to: Verification section below.





Checking Signal Cable Resistance To Ground
- Ignition OFF.
- Disconnect the transmission control module.
- Expose combined instrument panel connector.
- Disconnect combined instrument panel connector C.
- Connect an ohmmeter between # 8 and # 15 on test box.
- The ohmmeter should read infinite resistance.

If reading is OK:
- Proceed to: Checking For An Open-circuit section below.

If reading is incorrect:
- Proceed to: Checking For A Short-circuit section below.





Checking For An Open-circuit
- Check cable between combined instrument panel connector C terminal 12 and transmission control module # 8 for an open-circuit.
- Proceed to: Verification section below.





Checking For A Short-circuit
- Check cable between combined instrument panel connector C terminal 12 and transmission control module # 8 for a short-circuit to ground.
- Proceed to: Verification section below.





Checking Speedometer Ground
- Ignition OFF.
- Expose combined instrument panel.
- Connect test box to combined instrument panel connector A.
- Connect an ohmmeter between # A:4 and ground terminal 31/53.
- The ohmmeter should read approx. 0 Ohms.

If reading is OK:
- Proceed to: Checking For Contact Resistance And Oxidation section below.

If reading is incorrect:
- Proceed to: Checking For Contact Resistance And Oxidation 2 sections below.





Checking For Contact Resistance And Oxidation
- Ignition OFF.
- The diagnostic trouble code was caused by loose connections in the transmission control module and combined instrument panel connectors. Check transmission control module and combined instrument panel connectors for contact resistance and oxidation and remedy.
- Proceed to: Verification section below.





Checking For Contact Resistance And Oxidation
- Ignition OFF.
- Check ground terminals 31/53 and 31/67 for contact resistance and oxidation according.
- Check cable between ground terminal 31/67 and combined instrument panel connector A terminal 4 for contact resistance and oxidation.
- Proceed to: Verification section below.





Verification
After repairs have been completed they must be verified as follows to ensure that the fault has been eliminated:

- An alternative to the following method is to drive the car on the road.
- Ignition OFF.
- Reconnect connectors, reinstall components etc.
- Rear wheels raised.
- Engine idling.
- Go into scrolling values.
- Read off speed.
- Move the gear selector to position D so the rear wheels begin to rotate.
- Check that road speed corresponds to the speedometer reading.

NOTE:
- When the front wheels are stationary and the rear wheels rotate diagnostic trouble codes may can be stored in the ABS system. Erase any diagnostic trouble codes stored in the ABS system after fault-tracing.
- Ensure that the rear wheels are not rotating when the gear shift lever is moved.

- Does road speed correspond to speedometer reading?

Yes:
- Fault corrected.

No:
- Proceed to: Fault-tracing Information section below

Fault-tracing Information
The verification result shows that the fault persists.

- Do you want to exit fault-tracing?

Yes:
- Fault not corrected.

No:
- Proceed to: Checking The Speedometer section above.





Intermittent Fault
- Ignition OFF.
- Check vehicle speed sensor connector for contact resistance and oxidation.
- Check cable between combined instrument panel terminal C:12 and transmission control module # 8 for an intermittent open-circuit, intermittent short-circuit to ground and an intermittent short-circuit to supply voltage.
- Check speedometer circuits to ground terminal 31/67, vehicle speed sensor, ignition switch and terminal 0:12 for an intermittent open-circuit, intermittent short-circuit to ground and an intermittent short-circuit to supply voltage.
- Check ground terminals 31/67 and 31/53 for contact resistance and oxidation.
- Proceed to: Fault-tracing Information section below

Fault-tracing Information
For intermittent faults fault-tracing is not followed by a verification because the fault is not present at this moment.

- Do you want to repeat fault-tracing?

Yes:
- Proceed to: Checking The Speedometer section above.

No:
- Operation done.
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