Diagnostic Test

1) AAT SENSOR VOLTAGE BELOW 0.078 OF A VOLT
Ignition on, engine not running.

With a scan tool, read the AAT voltage.

Is the voltage below 0.078 of a volt?

Yes
1. Go To 2).
No
1. Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to ENGINE - STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
2) AAT SENSOR
Turn the ignition off.

Disconnect the AAT harness connector.

Ignition on, engine not running.

With a scan tool, read AAT voltage.

Is the voltage above 1.0 volt?

Yes
1. Replace the AAT Sensor.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to ENGINE - STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Go To 3).
3) (G31) AAT SIGNAL CIRCUIT SHORTED TO THE (G931) AAT RETURN CIRCUIT

Fig 1: MEASURING RESISTANCE BETWEEN THE AAT SIGNAL CIRCUIT AND AAT RETURN CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the C4 TIPM harness connectors.

Measure the resistance between the (G931) AAT Return circuit and the (G31) AAT Signal circuit in the AAT Sensor harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Repair the short to between the (G931) AAT Return circuit and the (G31) AAT Signal circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to ENGINE - STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Go To 4).
4) (G31) AAT SIGNAL CIRCUIT SHORTED GROUND

Fig 2: MEASURING RESISTANCE BETWEEN GROUND AND AAT SIGNAL CIRCUIT
Courtesy of DAIMLERCHRYSLER CORP.

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

Is the resistance below 100 ohms?

Yes
1. Repair the short to ground in the (G31) AAT Signal circuit.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to ENGINE - STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Go To 5).
5) TIPM
NOTE: Before continuing, check the TIPM 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
1. Repair as necessary.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to ENGINE - STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .
No
1. Replace and program the Totally Integrated Power Module in accordance with the Service Information.
2. Perform the POWERTRAIN VERIFICATION TEST. (Refer to ENGINE - STANDARD PROCEDURE - POWERTRAIN VERIFICATION TEST) .