Outside Temperature Display: Testing and Inspection

SELF-CHECK DIAGNOSTICS
With the ignition ON, the Compass/Temp Mirror can perform a diagnostic self-check by pressing and holding the Zone/Cal button (left reading lamp button) for 20 - 25 seconds. The internal diagnostics will sequence the following five tests:

1. VF segment display - Illuminates the segment patterns one at a time for 1 second each as follows:
- CAL
- ZONE
- N
- NE
- E
- SE
- S
- SW
- W
- NW
- 0 through 9
- degrees C
- degrees F

2. CTM memory - ROM Checksum
3. CTM memory - RAM
4. CTM memory - EEPROM
5. Compass Test

During the self-check, if any of the internal tests fail, the Compass/Temp Mirror will display an "F" and the number of the test that failed. If more than one test fails "FO" will be displayed. P- Pass or F- Fail will be displayed until the Zone/Cal button (left reading lamp button) is pressed and released or the ignition is cycled. If all of the tests pass, the Compass/Temp Mirror will display "P,'. A VF segment that fails to illuminate will not cause the

Compass/Temp Mirror to display an "F". If any segment fails to illuminate or the Compass/Temp Mirror displays "F", the Compass/Temp Mirror must be replaced.

To exit self-check diagnostics, press and release the Zone/Cal button or cycle the ignition to return to normal compass/temp operation.




Ambient Temperature Sensor Diagnostics
The outside temperature function is supported by the ambient temperature sensor; a signal and ground circuit hardwired to the compass/temp module (1.6L vehicles) or to the PCM (2.0L vehicles), and the Compass/Temp Mirror display.

If the Compass/Temp Mirror display indicates 60 degrees C (140 degrees F) or the ambient temperature sensor sense circuit is shorted to ground, the temp display will be 60 degrees C (140 degrees F) to indicate a SHORT circuit condition.

If the Compass/Temp Mirror display indicates -45 degrees C (-49 degrees F) or the ambient temperature sensor sense circuit is open, the temp display will be -45 degrees C (-49 degrees F) to indicate an OPEN circuit condition.

If there is an OPEN or SHORT circuit condition, it must be repaired before the Compass/Temp Mirror VF display can be tested.

The ambient temperature sensor can be diagnosed using the following Sensor Test. If there are no codes stored in the PCM (2.0L vehicles) and the ambient temperature sensor and the circuits are confirmed to be OK, but the temperature display is inoperative or incorrect, replace the Compass/Temp Mirror.



AMBIENT TEMPERATURE SENSOR TEST
1. Turn the ignition OFF.
2. Disconnect and isolate the battery negative cable.
3. Disconnect the ambient temperature sensor harness connector.
4. Measure the resistance of the ambient temperature sensor using the following values:

0 degrees C (32 degrees F) Sensor Resistance = 29.33 - 35.99 Kilohms
10 degrees C (50 degrees F) Sensor Resistance = 17.99 - 21.81 Kilohms
20 degrees C (68 degrees F) Sensor Resistance = 11.37 - 13.61 Kilohms
25 degrees C (77 degrees F) Sensor Resistance = 9.12 - 10.86 Kilohms
30 degrees C (86 degrees F) Sensor Resistance = 7.37 - 8.75 Kilohms
40 degrees C (104 degrees F) Sensor Resistance = 4.90 - 5.75 Kilohms

The sensor resistance should read between these min/max values. If the resistance value is OK, refer to the Wiring Diagrams to test the Signal and Ground circuits. If the resistance values are not OK, replace the Sensor.




Refer to Body Control System.
Body Control Module

Refer to The Programmable Communication Interface Multiplex System (PCI Bus).
Information Bus