Signal Faulty
Signal faulty
Checking the speedometer
Did the speedometer work during driving?
Yes - Checking the speed signal
No - Checking the component
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Checking the component
- Troubleshoot the speedometer.
Select Continue when fault has been rectified.
Continue - FAULT FOUND
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Checking the speed signal
- Ignition off.
- Disconnect the control unit.
- Raise the car so that the front wheels hang free.
- Ignition on.
Connect a voltmeter between control unit connector pin 8S and ground.
Then slowly spin the front RH wheel by hand.
The voltmeter should vary between battery voltage and approx. 0.4 V when the wheel is spun.
- 1. the value is OK.
- 2. the voltmeter displays a constant battery voltage.
- 3. the voltmeter displays approx. 0 V continuously.
Select one of the options above.
1 - Checking for contact resistance and oxidation
2 - Connecting test box to dashboard
3 - Checking the component
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Checking for contact resistance and oxidation
- Ignition off.
- The cause of the trouble code is poor contact in the control unit connector. Check control unit connector pin 8S for contact resistance and oxidation as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault , and for a loose contact as described in Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Select Continue when fault has been rectified.
Continue - FAULT FOUND
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Connecting test box to dashboard
Connecting up the Test box to dashboard
Is the test box connected to the dashboard?
Yes - FAULT FOUND
No -
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Connecting test box
- Ignition off.
- Expose dashboard as per.
- Undo dashboard connector.
Connecting test box to dashboard:
- Connect test box to dashboard connector A and B.
Press Continue.
Continue -
Connect test box to dashboard connector A and B. Test as per. VDO signal table, column # 4
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Checking ground points
- Ignition off.
- Switch off anything which might drain the battery.
- Connect an ohmmeter between:
- # 15 (# A15) on test box and battery - terminal.
- # 17 (# A17) on test box and battery + terminal.
Ohmmeter should read 0 ohms both times.
OK - FAULT FOUND
OK - Go back to fault-tracing where you left off.
Not OK - Check ground points 31/50 and 31/51 on the electrical control panel and leads connecting to them for open-circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check ground lead between electrical control panel and chassis for open-circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
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Checking for open-circuit and contact resistance
- Check ground points 31/50 and 31/51 on the electrical control panel and leads connecting to them for open-circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Check ground lead between electrical control panel and chassis for open-circuit as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and contact resistance as per Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Press Continue when fault is repaired.
Continue - FAULT FOUND
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FAULT FOUND - Checking the component
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Checking the component
- Ignition on.
- Control unit disconnected.
- Connect a mains tester with at least 3 W between control unit connector pin 8S and ground.
Does the mains tester lamp light?
Yes - Checking for a short circuit
No - Checking for an open circuit
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Checking for a short circuit
- Ignition off.
- Check the wire between control unit connection 8S and combined instrument connection A7 as well as the wire between engine control module connection B18 and combined instrument connection A7 for a short circuit to voltage supply as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select Continue when fault has been rectified.
Continue - FAULT FOUND
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Checking for an open circuit
- Ignition off.
- Check the wire between combined instrument connection A7 and 53-pin connector pin 24/13 for an open circuit as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select Continue when fault has been rectified.
Continue - FAULT FOUND
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Connecting test box to dashboard
FAULT FOUND - Checking the component
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Checking the component
- Ignition off.
- Control unit disconnected.
- Disconnect the engine control unit.
- Access the combined instrument as described in.
- Connect an ohmmeter between control unit connection 8S and combined instrument connection A:7.
The resistance should be 0 ohms
OK - Checking for a short circuit
Not OK - Checking for an open circuit
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Checking for a short circuit
- Ignition off.
- Check the wire between control unit connection 8S and combined instrument connection A7 as well as the wire between engine control module connection B18 and combined instrument connection A7 for a short circuit to ground as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select Continue when fault has been rectified.
Continue - FAULT FOUND
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Checking for an open circuit
- Ignition off.
- Check the lead between the combined instrument connector pin A7 and control unit connector pin 8S for an open circuit as described in Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select Continue when fault has been rectified.
Continue - FAULT FOUND
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