Diagnostic Test

Ignition on, engine not running.

With a scan tool, read the IAT voltage.

Is the voltage below 0.078 of a volt? 

Yes 

1. Go To  2).

No 

1. Refer to INTERMITTENT CONDITION .
2. Perform POWERTRAIN VERIFICATION TEST .

Turn the ignition off.

Disconnect the IAT Sensor harness connector.

Ignition on, engine not running.

With a scan tool, read IAT voltage.

Is the voltage above 4.5 of a volts? 

Yes 

1. Replace the Intake Air Temperature Sensor.
2. Perform POWERTRAIN VERIFICATION TEST .

No 

1. Go To  3).

Fig 1: Checking Intake Air Temperature Sensor Signal Circuit

Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the PCM harness connectors.

Measure the resistance between ground and the (K21) IAT Sensor Signal circuit in the IAT Sensor harness connector.

Is the resistance below 100 ohms? 

Yes 

1. Repair the short to ground in the (K21) IAT Sensor Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .

No 

1. Go To  4).

Fig 2: Checking Intake Air Temperature Sensor Signal Circuit & Ground Circuit

Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance between the (K21) IAT Sensor Signal circuit and the (K900) Sensor ground circuit in the IAT Sensor harness connector.

Is the resistance below 100 ohms? 

Yes 

1. Repair the short between the (K900) Sensor ground circuit and the (K21) IAT Sensor Signal circuit.
2. Perform POWERTRAIN VERIFICATION TEST .

No 

1. Go To  5).

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 POWERTRAIN VERIFICATION TEST .

No 

1. Replace and program the Powertrain Control Module per Service Information.
2. Perform POWERTRAIN VERIFICATION TEST .