Signal Too High. Permanent Fault

Signal too high. Permanent fault

Checking the connector




- Ignition off
- Intake air temperature (IAT) sensor connector disconnected.
Check the connector for contact resistance and oxidation according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.





Were any faults found?

Yes - Verification

No - Checking the ground lead

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Checking the ground lead
Connect an ohmmeter between the intake air temperature (IAT) sensor connector terminal #2 (control module side) and ground.









The ohmmeter should read approximately 0 ohms.

OK - Checking the signal cable

Not OK - Checking wiring and terminals

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Checking the signal cable








- Ignition on
- Disconnect the intake air temperature sensor connector.
Connect a voltmeter between the intake air temperature (IAT) sensor connector terminal #1 (control module side) and ground.
The voltmeter should read approximately 5 V.
1. more than 5 V
2. approximately 5 V
3. 0 V.









Select one of the above options:

1 - Checking wiring and terminals

2 - Defective intake air temperature (IAT) sensor

3 - Checking wiring and terminals

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Checking wiring and terminals
Check the cable between intake air temperature (IAT) sensor connector terminal #1 (engine control module (ECM) side) and engine control module (ECM) terminal #48. Check for a short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.













Continue - Verification

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Defective intake air temperature (IAT) sensor
Try a new intake air temperature (IAT) sensor according to Replacing the intake air temperature sensor Service and Repair.

Continue - Verification

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Checking wiring and terminals
Check the cable between intake air temperature (IAT) sensor connector terminal #1 (engine control module (ECM) side) and engine control module (ECM) terminal #48. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Check the cable between intake air temperature (IAT) sensor connector terminal #2 (engine control module (ECM) side) and engine control module (ECM) terminal #79. Check for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.













Continue - Verification

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Verification




Verification

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








- Reconnect the connectors, reinstall components etc.
- Start the engine. Let the engine idle.
Read off diagnostic trouble codes (DTCs).
Check that the status of the diagnostic trouble code (DTC) has changed to intermittent. The fault has been remedied if the status of the diagnostic trouble code (DTC) has changed to intermittent.





Has the status of the diagnostic trouble code (DTC) changed to intermittent?

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 the connector

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