Signal Too Low

Signal too low

Checking water pump function




- Ignition on.
- Activate water pump.
Listen for a buzzing sound which shows that the water pump is running.





Does the water pump function?

Yes - Intermittent fault

No - Checking the connectors

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Checking the connectors








- Ignition off.
- Remedy water pump and control module connector for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check any damage etc.
- Reinstall components, reconnect connectors etc.
- Ignition on.
- Activate water pump.
Listen for a buzzing sound which shows that the water pump is running.
If the water pump now functions it means that the cause of the fault has been loose connections in the connections.

Other information:
- To access the control module/connect breakout box see.
- To access/replace the water pump see Replacing water pump Replacing Water Pump.





Does the water pump function?

Yes - FAULT FOUND

No - Checking component and cables

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Checking component and cables
Check cable between control module #12 and water pump terminal 1 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check cable between control module #11 and water pump terminal 2 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
If no fault is found on the cable the water pump should be changed.

Note! Diagnostic trouble code (DTC) HEA-815 Combustion fan signal and/or diagnostic trouble code (DTC) HEA-825 Fuel pump (FP) signal may also be stored if there is a fault in the power cable.

Remedy as necessary.

Other information:
- To access the control module/connect breakout box see.
- To access/replace the water pump see Replacing water pump Replacing Water Pump.
- For other values, see Signal specification Additional heater 912-D/B Signal Specification Additional Heater 912-D/B.













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.
- Ignition on.
- Activate water pump.
Listen for a buzzing sound which shows that the water pump is running.





Does the water pump function?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFICATION FAILED - Fault-tracing information

VERIFIED - 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 - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Checking water pump function

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Intermittent fault
Check water pump and control module connector for contact resistance and oxidation according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Check cable between control module #12 and water pump terminal 1 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults and a short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Check cable between control module #11 and water pump terminal 2 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
Remedy as necessary.

Other information:
- To access the control module/connect breakout box see.
- To access/replace the water pump see Replacing water pump Replacing Water Pump.
- For other values, see Signal specification Additional heater 912-D/B Signal Specification Additional Heater 912-D/B.













Continue - Fault-tracing information
DONE

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Fault-tracing information




Information

Fault-tracing information
If the fault is intermittent, do not verify fault-tracing if the fault does not recur.
It is possible to view the information again, or leave fault-tracing for this diagnostic trouble code (DTC).

Do you want to view the information again?

Yes - Attempt New Test

No - FAULT FOUND

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Attempt New Test - Checking water pump function

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