Signal Too Low. Permanent Fault

Signal too low. Permanent fault

EFI-123 Engine coolant temperature (ECT) sensor, signal

Checking the signal cable

Warning! Before fault-tracing, disconnect engine cooling fan (FC) relay connector A so that the engine cooling fan (FC) will not run. The diagnostic trouble code (DTC) EFI-514 Engine cooling fan (FC) low-speed, signal may be stored. After fault-tracing the connector must be re-connected.








- Ignition on.
- Disconnect temperature sensor.
Select Volvo Scan Tool (ST) to read off the voltage across the engine coolant temperature (ECT) sensor.





The reading should be approximately 5 V.

OK - Replacing component

Not OK - Checking for a short-circuit

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Replacing component
- Try a new engine coolant temperature (ECT) sensor.





Continue - Verification

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Checking for a short-circuit








- Check cable between temperature sensor terminal 1 and engine control module (ECM) #A31 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification

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Verification




Verification

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








- Ignition off.
- Reconnect connectors, reinstall components etc.
- Start engine and run to normal operating temperature. The engine should be hot enough for the thermostat to open.
- Select the Volvo Scan Tool (ST) symbol to read off engine coolant temperature (ECT).





Is the engine coolant temperature (ECT) value within its permitted range.

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 the signal cable

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