Temperature Display Inaccurate Or Inoperative - Dodge Ram 2004 Service Manual

COMPASS/MINI-TRIP COMPUTER
Symptom:

*TEMPERATURE DISPLAY INACCURATE OR INOPERATIVE

AMBIENT TEMPERATURE SENSOR
COMPASS/MINI-TRIP COMPUTER
TEST
1 NOTE: Diagnose and repair any FCM, CMTC, PCM, or Communication
DTCs before proceeding with this test.
NOTE: The Ambient Temperature Sensor is hardwired to the FCM (Diesel),
or to the PCM. Ambient temperature information is transmitted to the
CMTC via the PCI Bus.
Turn the ignition off.
Disconnect the Ambient Temperature Sensor harness connector.
Measure the resistance of the Ambient Temperature Sensor using the following
temperature/resistance values:
10°C (50°F) Sensor Resistance = 17.99 - 21.81 Kilohms
20°C (68°F) Sensor Resistance = 11.37 - 13.61 Kilohms
25°C (77°F) Sensor Resistance = 9.12 - 10.88 Kilohms
30°C (86°F) Sensor Resistance = 7.37 - 8.75 Kilohms
40°C (104°F) Sensor Resistance = 4.90 - 5.75 Kilohms
50°C (122°F) Sensor Resistance = 3.33 - 3.88 Kilohms
Is the Ambient Temperature Sensor resistance measurement within the min/max
specifications?
Yes → Go To 2
→ Replace the Ambient Temperature Sensor.
No
2 Perform the CMTC self test.
Turn the ignition off.
Press and hold the C/T and Reset buttons.
Turn the ignition on.
NOTE: The self test can also be performed using the DRBIII .
Observe the CMTC display at the conclusion of the self test.
Does the CMTC display Passed Self Test ?
Yes → Test Complete.
→ Replace and configure the CMTC in accordance with the Service
No
POSSIBLE CAUSES
ACTION
Perform BODY VERIFICATION TEST - VER 1.
Information.
Perform BODY VERIFICATION TEST - VER 1.
314
APPLICABILITY
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All