Signal Too Low - Permanent Fault

Signal too low. Permanent fault

Checking the connector








- Ignition off
- Check the intake air temperature (IAT) sensor connector. Check for contact resistance and oxidation
- Reinstall the components, reconnect the connectors etc.
- Ignition on
- Read off the signal from the intake air temperature (IAT) sensor.
Check that the signal is within its permitted range. The voltage may vary between 0.17 V and 4.9 V depending on the air temperature. At 20° C voltage should be approximately 3.5 V.
If the signal is now OK, the fault was caused by poor contact in the connector.

Other information
- To access or replace the intake air temperature (IAT) sensor, see Temperature and pressure sensor, replacing Service and Repair
- Checking wiring and terminals Checking Wiring And Terminals.













Is the signal OK?

Yes - Fault Found

No - Checking the wiring and component

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Checking the wiring and component
Check the Intake Air Temperature (IAT) sensor resistance.

Note! The intake air temperature (IAT) sensor may be defective if there gas been a short-circuit to supply voltage in the signal cable. Check this before replacing the sensor.

Check the signal cable between control module terminal #A5 (#A5) and intake air temperature (IAT) sensor connector terminal #1. Check for an open-circuit. Check for a short-circuit to supply voltage.

Hint: With the ignition on and the intake air temperature (IAT) sensor connector disconnected, the voltage between terminal #1 and ground must be approximately 5 V.

Check the ground lead between control module terminal #A60 (#A60) and intake air temperature (IAT) sensor connector terminal #2. Check for an open-circuit.
Remedy as necessary.

Other information
- To connect the breakout box / access the control module, see Connecting the breakout box, B5244T5, B5254T2 Connecting the Breakout Box
- To access or replace the intake air temperature (IAT) sensor, see Temperature and pressure sensor, replacing Service and Repair
- For resistance values, see Component specifications Specifications
- For information about signals on 5 cylinder engines, see Signal specification Signal Specification, ECM
- For information about signals on 6 cylinder engines, see Signal specification Signal Specification, ECM
- Checking wiring and terminals Checking Wiring And Terminals.














Continue - Verification

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Verification




Verification

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








- Ignition off.
- Reconnect connectors, reinstall components
- Ignition on.
- Read off the intake air temperature (IAT).
The Intake Air Temperature (IAT) sensor is integrated into the Mass Air Flow (MAF) sensor.









Is the temperature within its permitted range?

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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - FAULT-TRACING FAILED

Attempt New Test - Checking the connector

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