Compass/Mini-Trip Test 4A - Incorrect Ambient Temperature Reading
NOTE:
Perform COMPASS/MINI-TRIP TEST 1A
before proceeding. For connector terminal ID, see CONNECTOR IDENTIFICATION
and WIRING DIAGRAM. Perform TEST VER-1A
after each repair.
CAUTION:
Always turn ignition switch to OFF position prior to disconnecting any module connector. Ensure all connectors are clean and tight.
- Disconnect and remove the ambient temperature sensor. See Figure
under COMPASS/MINI-TRIP TEST 2A
. Using an ohmmeter, measure ambient temperature sensor resistance. Compare reading with AMBIENT TEMPERATURE SENSOR RESISTANCE VALUES
table.NOTE: After repairing temperature reading problem, drive vehicle at least 3 miles at a steady speed above 25 MPH to update compass/mini-trip computer display.
- If ambient temperature sensor is not within specified resistance values, replace ambient temperature sensor. If ambient temperature sensor is within specified resistance values, go to next step.
- Turn ignition off. Close all doors. Turn all lights and accessories off. Using scan tool in ohmmeter mode, probe ambient temperature sensor connector terminal No. 1 (Light Green/White wire). If resistance is less than 5 ohms, go to step 6). If resistance is 5 ohms or more, go to next step.
- Connect jumper wire between ambient temperature sensor connector terminal No. 1 (Light Green/White wire) and chassis ground. Disconnect Body Control Module (BCM) Black 24-pin connector.
- Using scan tool in ohmmeter mode, probe BCM Black 24-pin connector terminal No. 2 (Light Green/White wire). If resistance is 5 ohms or more, repair open Light Green/White wire. If resistance is less than 5 ohms, replace BCM.
- Reconnect ambient temperature sensor. Disconnect BCM Black 24-pin connector. Using an ohmmeter, measure resistance between BCM Black 24-pin connector terminals No. 5 (Dark Green/Red wire) and No. 2 (Light Green/White wire). Compare reading with AMBIENT TEMPERATURE SENSOR RESISTANCE VALUES table.
- If ambient temperature sensor is within specified resistance values, replace BCM. If ambient temperature sensor is not within specified resistance values, go to next step.
- Disconnect ambient temperature sensor connector. Using scan tool in ohmmeter mode, probe ambient temperature sensor connector terminal No. 1 (Light Green/White wire). If resistance is less than 500,000 ohms, repair short in Light Green/White wire. If resistance is 500,000 ohms or more, go to next step.
- Using scan tool in ohmmeter mode, probe ambient temperature sensor connector terminal No. 2 (Dark Green/Red wire). If resistance is less than 500,000 ohms, repair short in Dark Green/Red wire. If resistance is 500,000 ohms or more, repair short between ambient temperature sensor Dark Green/Red wire and Light Green/White wire.
AMBIENT TEMPERATURE SENSOR RESISTANCE VALUES
| Degrees: F (C) | Ohms |
|---|---|
| 32 (0) | 29,300-36,000 |
| 50 (10) | 18,000-22,000 |
| 68 (20) | 11,400-13,600 |
| 77 (25) | 9100-10,800 |
| 86 (30) | 7400-8700 |
| 104 (40) | 4900-5700 |
| 122 (50) | 3300-3800 |