Dodge Ram Truck 1500-2500-3500. Manual — part 785

P0071-AMBIENT AIR TEMPERATURE SENSOR PERFORMANCE (CONTINUED)

2.

(G31) AAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE

Turn the ignition off.

Disconnect the C2 PCM harness connector.

Disconnect the AAT Sensor harness connector.

NOTE: Visually inspect both the component and the PCM connec-
tors. Look for damaged, partially broken wires, and backed out or
corroded terminals.
Ignition on, engine not running.

Measure the voltage on the (G31) AAT Signal circuit in the AAT Sen-
sor harness connector.

Is the voltage above 0 volts?

Yes

>> Repair the short to voltage in the (G31) AAT Signal circuit.

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

No

>> Go To 3

3.

AAT SENSOR VOLTAGE ABOVE 4.6 VOLTS

Turn the ignition off.

Connect the C2 PCM harness connector.

Ignition on, engine not running.

With a scan tool, read the AAT voltage.

Is the voltage above 4.6 volts?

Yes

>> Go To 4

No

>> Go To 7

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ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

DR/DH

P0071-AMBIENT AIR TEMPERATURE SENSOR PERFORMANCE (CONTINUED)

4.

AAT SENSOR

Connect a jumper wire between the (G31) AAT Signal circuit and the
(K900) Sensor ground circuit in the AAT Sensor harness connector.

With a scan tool, read the AAT voltage.

Is the voltage below 1.0 volt with the jumper wire installed?

Yes

>> Replace the AAT Sensor.

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

No

>> Go To 5

NOTE: Remove the jumper wire before continuing.

5.

(G31) AAT SIGNAL CIRCUIT OPEN

Turn the ignition off.

Disconnect the C2 PCM harness connector.

CAUTION: Do not probe the PCM harness connectors. Probing
the PCM harness connectors will damage the PCM terminals
resulting in poor terminal to pin connection. Install Miller Special
Tool #8815 to perform diagnosis.
Measure the resistance of the (G31) AAT Signal circuit from the AAT
Sensor harness connector to the appropriate terminal of special tool
#8815.

Is the resistance below 5.0 ohms?

Yes

>> Go To 6

No

>> Repair the open in the (G31) AAT Signal circuit.

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

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

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P0071-AMBIENT AIR TEMPERATURE SENSOR PERFORMANCE (CONTINUED)

6.

(K900) SENSOR GROUND CIRCUIT OPEN

Measure the resistance of the (K900) Sensor ground circuit from the
AAT Sensor harness connector to the appropriate terminal of special
tool #8815.

Is the resistance below 5.0 ohms?

Yes

>> Go To 9

No

>> Repair the open in the (K900) Sensor ground circuit.

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

7.

(G31) AAT SIGNAL CIRCUIT SHORTED TO GROUND

Turn the ignition off.

Disconnect the C2 PCM harness connector.

Measure the resistance between ground and the (G31) AAT Signal cir-
cuit in the AAT Sensor harness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short to ground in the (G31) AAT Signal circuit.

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

No

>> Go To 8

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ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

DR/DH

P0071-AMBIENT AIR TEMPERATURE SENSOR PERFORMANCE (CONTINUED)

8.

(G31) AAT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT

Measure the resistance between the (G31) AAT Signal circuit and the
(K900) Sensor ground circuit in the AAT Sensor harness connector.

Is the resistance below 5.0 ohms?

Yes

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

and the (G31) AAT Signal circuit.

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

No

>> Go To 9

9.

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.

Were there any problems found?

Yes

>> Repair as necessary.

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

No

>> Replace and program the Powertrain Control Module per Service Information.

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

DR/DH

ENGINE - ELECTRICAL DIAGNOSTICS - 3.7L/4.7L/5.7L

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