Diagnostic Test

ACTIVE DTC
1. Ignition on, engine not running.
2. With a scan tool, read DTCs.
  Is the DTC active at this time?
  
  Yes
  - Go to step 2
  No
  - Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
IAT SENSOR VOLTAGE ABOVE 4.6 VOLTS
1. Turn the ignition off.
2. Disconnect the IAT Sensor harness connector.
3. Ignition on, engine not running.
4. With a scan tool, read the IAT voltage.
  Is the voltage above 4.6 volts?
  
  Yes
  - Go to step 3
  No
  - Go to step 4
IAT SENSOR

Fig 1: Checking IAT Signal Circuit
Courtesy of CHRYSLER LLC
1. Connect a jumper wire between the (K21) IAT Signal circuit and the (K900) Sensor ground circuit in the IAT Sensor harness connector.
2. With a scan tool, read the IAT voltage.
  Is the voltage below 1.0 volt with the jumper wire installed?
  
  Yes
  - Replace the IAT Sensor.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
  No
  - Go to step 4
    NOTE: Remove the jumper wire before continuing.
EXCESSIVE RESISTANCE IN THE (K21) IAT SIGNAL CIRCUIT
1. Turn the ignition off.
2. 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 PCM Pinout Box 8815 and PCM Pinout Box Adapter 8815-1 to perform diagnosis.
3. Using a voltmeter perform a voltage drop test. Backprobe the (K21) IAT Signal circuit at the IAT Sensor harness connector and probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.
  WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
4. Start the engine and allow it to reach normal operating temperature.
5. Monitor the voltmeter.
  Is the voltage below 0.5 of a volt?
  
  Yes
  - Go to step 5
  No
  - Repair the open in the (K21) IAT Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
1. Turn the ignition off.
2. Move the voltmeter leads to backprobe the (K900) Sensor Ground circuit at the IAT Sensor harness connector and to probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.
  WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.
3. Start the engine and allow it to reach normal operating temperature.
4. Monitor the voltmeter.
  Is the voltage below 0.5 of a volt?
  
  Yes
  - Go to step 6
  No
  - Repair the open in the (K900) Sensor ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
PCM
NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
1. 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. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure
  No
  - Replace and program the Powertrain Control Module per Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. See DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure