FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Signal Too Low






Signal too low

Checking the connector








- Ignition off
- Check the boost pressure sensor connector. Check for contact resistance and oxidation.

Note! The intake air temperature (IAT) sensor is integrated in the boost pressure sensor

- Reinstall the components, reconnect the connectors etc.
- Ignition on
- Read off the intake air temperature (IAT).
Check that the intake air temperature (IAT) is within its permitted range. If the intake air temperature (IAT) is now within its permitted range, the fault was caused by loose connections in the connector.

Other information:
- To access or replace the intake air temperature (IAT) sensor, see Temperature and pressure sensor, replacing Service and Repair.













Is the temperature within its permitted range?

Yes - Fault Found

No - Checking the wiring and component

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Checking the wiring and component




- Ignition off.
Check the intake air temperature (IAT) sensor resistance between terminals #1 and #2 on the boost pressure sensor.

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 boost pressure sensor terminal #2. Check for a short-circuit to supply voltage. Check for an open-circuit.

Hint: With the ignition on and the boost pressure sensor connector disconnected, the voltage between terminal #2 and ground must be approximately 5 V.

Check the ground lead between control module terminal #A60 (#A60) and boost pressure sensor terminal #1. Check for an open-circuit.
If no errors are found and the fault is permanent, replace the intake air temperature (IAT) sensor.
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 Description / Specification
- For information about signals on 6 cylinder engines, see Signal specification Signal Description / Specification
- 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 the connectors, reinstall components etc.
- Ignition on
- Read off the intake air temperature (IAT).





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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