Dodge Ram Truck 1500-2500-3500. Manual — part 1262

P1493-AMBIENT/BATTERY TEMPERATURE SENSOR VOLTAGE TOO LOW

9 - 1970

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

DR/DH

P1493-AMBIENT/BATTERY TEMPERATURE SENSOR VOLTAGE TOO LOW (CONTINUED)

For the Engine circuit diagram (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES/ENGINE CON-
TROL MODULE - SCHEMATIC - ELECTRICAL)

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
With the ignition on.

•

Set Condition:
The PCM senses the voltage from the Battery Temperature Sensor below 0.5 of a volt for 3 seconds.

Possible Causes

BATTERY TEMP SENSOR VOLTAGE BELOW 0.5 OF A VOLT

BATTERY TEMPERATURE SENSOR

(K25) BATTERY TEMP SIGNAL CIRCUIT SHORTED TO GROUND

(K25) BATTERY TEMP SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND

PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)

1.

BATTERY TEMP SENSOR VOLTAGE BELOW 0.5 OF A VOLT

Ignition on, engine not running.

Record all DTCs and the related Freeze Frame data.

With scan tool, monitor the Ambient/Battery Temperature Sensor voltage.

Is the voltage below 0.5 of a volt?

Yes

>> Go To 2

No

>> Refer to the INTERMITTENT CONDITION Symptom (Diagnostic Procedure).

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

2.

BATTERY TEMPERATURE SENSOR

Ignition on, engine not running.

With the scan tool in sensors, read the Battery Temp Sensor voltage.

Disconnect the Battery Temp Sensor harness connector.

Did the Battery Temperature Sensor voltage change from below 1.0 volt to above 4.5 volts?

Yes

>> Replace the Battery Temperature Sensor.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No

>> Go To 3

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

9 - 1971

P1493-AMBIENT/BATTERY TEMPERATURE SENSOR VOLTAGE TOO LOW (CONTINUED)

3.

(K25) BATTERY TEMP SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.

Disconnect the PCM harness connectors.

Measure the resistance between ground and the (K25) Battery Temp
Signal circuit at the Battery Temp Sensor harness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short to ground in the (K25) Batt Temp Signal

circuit.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9
- ENGINE - STANDARD PROCEDURE)

No

>> Go To 4

4.

(K25) BATTERY TEMP SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND

Measure the resistance between the (K25) Battery Temp Signal circuit
and the (K900) Sensor ground circuit at the Battery Temp Sensor har-
ness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short between the (K900) Sensor ground circuit

and the (K25) Batt Temp Signal circuit.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9
- ENGINE - STANDARD PROCEDURE)

No

>> Go To 5

5.

PCM

NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.

If there are no possible causes remaining, view repair.

Repair

Replace and program the Powertrain Control Module per Service Information.

Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

9 - 1972

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

DR/DH

P1494-LEAK DETECTION PUMP SWITCH OR MECHANICAL FAULT

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - SRT-10

9 - 1973