Dodge Ram Truck 1500-2500-3500. Manual — part 457

FCM - AMBIENT TEMP SENSOR INPUT LOW (CONTINUED)

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 Tem-
perature Sensor Signal circuit.

Is the resistance below 5.0 ohms?

Yes

>> Repair the (G31) Ambient Temperature Sensor Signal cir-

cuit for a short to ground.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

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 Sen-
sor Signal circuit and the (G180) Ambient Temperature Sensor Ground
circuit.

Is the resistance below 5.0 ohms?

Yes

>> Repair the (G31) Ambient Temperature Sensor Signal cir-

cuit for a short to the (G180) Ambient Temperature Sensor
Ground circuit..

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

No

>> Replace the Front Control Module in accordance with the

Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

8M - 8

OVERHEAD CONSOLE - ELECTRICAL DIAGNOSTICS

DR/DH

FCM - AMBIENT TEMP SENSOR INPUT OPEN

For the Electronic Overhead Module circuit diagram (Refer to 8 - ELECTRICAL/OVERHEAD CONSOLE - SCHE-
MATICS AND DIAGRAMS).

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
Continuous with the ignition on.

•

Set Condition:
The FCM detects more than 5.0 volts on the Ambient Temperature Sensor Signal circuit.

Possible Causes

(G31) AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE

(G930) AMBIENT TEMPERATURE SENSOR GROUND CIRCUIT OPEN

(G31) AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT OPEN

AMBIENT TEMPERATURE SENSOR

1.

AMBIENT TEMPERATURE SENSOR

Disconnect the Ambient Temperature Sensor harness connector.

Connect a jumper wire between the sensor signal and sensor ground
circuits.

Close all vehicle doors.

Turn the ignition on.

With the DRBIII

T

in Sensors, read the Ambient Temperature Sensor

voltage.

Is the voltage below 0.5 volts?

Yes

>> Replace the Ambient Temperature Sensor.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

No

>> Go To 2

DR/DH

OVERHEAD CONSOLE - ELECTRICAL DIAGNOSTICS

8M - 9

FCM - AMBIENT TEMP SENSOR INPUT OPEN (CONTINUED)

2.

CHECK THE (G31) AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE

Turn the ignition off.

Disconnect the IPM C3 harness connector.

Turn the ignition on.

Measure the voltage between the (G31) Ambient Temperature Sensor
Signal circuit and ground.

Is there any voltage present?

Yes

>> Repair the (G31) Ambient Temperature Sensor Signal cir-

cuit for a short to voltage.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

No

>> Go To 3

3.

CHECK THE (G180) AMBIENT TEMPERATURE SENSOR GROUND CIRCUIT FOR AN OPEN

Turn the ignition off.

Measure the resistance of the (G180) Ambient Temperature Sensor
Ground circuit between the IPM C3 harness connector and the Ambi-
ent Temperature Sensor harness connector.

Is the resistance above 5.0 ohms?

Yes

>> Repair the (G180) Ambient Temperature Sensor Ground

circuit for an open.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

No

>> Go To 4

8M - 10

OVERHEAD CONSOLE - ELECTRICAL DIAGNOSTICS

DR/DH

FCM - AMBIENT TEMP SENSOR INPUT OPEN (CONTINUED)

4.

CHECK THE (G31) AMBIENT TEMPERATURE SENSOR SIGNAL CIRCUIT FOR AN OPEN

Measure the resistance of the (G31) Ambient Temperature Sensor Sig-
nal circuit between the IPM C3 harness connector and the Ambient
Temperature Sensor harness connector.

Is the resistance above 5.0 ohms?

Yes

>> Repair the (G31) Ambient Temperature Sensor Signal cir-

cuit for an open.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

No

>> Replace the Front Control Module in accordance with the

Service Information.

Perform BODY VERIFICATION TEST - VER 1. (Refer to
BODY VERIFICATION TEST - VER 1.)

DR/DH

OVERHEAD CONSOLE - ELECTRICAL DIAGNOSTICS

8M - 11