FCM - Ambient Temp Sensor Input Low

FCM - AMBIENT TEMP SENSOR INPUT LOW

FCM - Ambient Temp Sensor Input Low:

WHEN MONITORED
Continuous with the ignition on.

SET CONDITION
The FCM detects less than 0.5 volts on the Ambient Temperature Sensor Signal circuit.

POSSIBLE CAUSES
- (G31) Ambient temperature sensor signal circuit shorted to ground
- (G31) Ambient temperature sensor signal circuit shorted to the (G180) ambient temperature sensor ground circuit
- Ambient temperature sensor

Diagnostic Test

1. AMBIENT TEMPERATURE SENSOR




Disconnect the Ambient Temperature Sensor harness connector.
Close all vehicle doors.
Turn the ignition on.
With the DRBIII(R) in Sensors, read the Ambient Temperature Sensor voltage.

Q: Is the voltage above 4.8 volts?

YES: Replace the Ambient Temperature Sensor. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 2

2. CHECK THE (G31) AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO GROUND




Turn the ignition off.
Disconnect the IPM C3 harness connector.
Measure the resistance between ground and the (G31) Ambient Temperature Sensor Signal circuit.

Q: Is the resistance below 5.0 ohms?

YES: Repair the (G31) Ambient Temperature Sensor Signal circuit for a short to ground. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. CHECK THE (G31) AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO THE (G180) AMBIENT TEMPERATURE SENSOR GROUND CIRCUIT




Measure the resistance between the (G31) Ambient Temperature Sensor Signal circuit and the (G180) Ambient Temperature Sensor Ground circuit.

Q: Is the resistance below 5.0 ohms?

YES: Repair the (G31) Ambient Temperature Sensor Signal circuit for a short to the (G180) Ambient Temperature Sensor Ground circuit. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the Front Control Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test