Signal Too Low - Permanent Fault

ECM-1100 OUTSIDE TEMPERATURE SENSOR
SIGNAL TOO LOW - PERMANENT FAULT

Checking connector



- Ignition off
- Check wiring and connectors for contact resistance and oxidation according to [1][2]Checking Wiring and Terminals. Permanent Fault
- Reinstall components, reconnect connectors etc.
- Ignition on.
- Read outside temperature.

If the temperature is now within its permitted range, the fault was caused by loose connections in the connector.

Other information
- To access/replace the outside temperature sensor, Outside Temperature Sensor, Replacing

Is the signal OK?
Yes - Testing Complete.
No - Continue below.


Checking Wiring And Components



Check outside temperature sensor resistance.

NOTE: The outside temperature sensor can be defective if the signal cable has been short-circuited to Supply voltage. Check this before replacing the sensor.

Check signal cable between control module #B29 (#B39) and outside temperature sensor #1 for an intermittent open-circuit according to [1][2]Checking Wiring and Terminals. Permanent Fault and a short-circuit to supply voltage according to [1][2]Checking Wiring and Terminals. Permanent Fault

Hint: With the ignition on and the outside temperature sensor connector disconnected, the voltage between #1 and ground should be approximately 5 V.

Check the ground lead between control module #B2 (#B12) and the outside temperature sensor #2 for an open-circuit according to [1][2]Checking Wiring and Terminals. Permanent Fault

Remedy as necessary.

Other Information
- Connecting the breakout box/accessing the control module, Connecting the Breakout Box (ECM)
- To access/replace the outside temperature sensor, Outside Temperature Sensor, Replacing
- For resistance values, see Component Specifications. Specifications
- For information about signals, see Diagnostic Parameters and Pinout Values. Signal Description, ME7, B5XX4T


Verification



Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reconnect connectors, reinstall components.
- Ignition on.
- Read outside temperature.

Is the temperature within its permitted range?
Yes - Testing Complete.
No - Continue below.


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.