Diagnostic Test

COMPARE THE INTAKE AIR TEMPERATURE
1. Turn the ignition off.
2. Allow the vehicle to sit with the ignition off in an environment where the temperature is consistent and above -7°C (19.4°F) until the engine coolant temperature is equal to ambient temperature.
3. Turn the ignition on.
4. With the scan tool, compare the AAT, ECT and IAT Sensor values.
  Is the Intake Air Temperature Sensor value within 15°C (59°F) of the other two sensor values?
  
  Yes
  - Go To 2
  No
  - Go To 3
ACTIVE DTC
1. Turn the ignition off.
2. If possible, allow the vehicle to sit with the ignition off for more than 480 minutes in an environment where the temperature is consistent and above -7°C (19.4°F).
3. Test drive the vehicle. The vehicle must exceed 48 km/h (30 mph) during the test drive. Do not cycle the ignition off when the test drive is completed.
4. With the scan tool, select View DTCs.
  Is the DTC Active or Pending at this time?
  
  Yes
  - Go To 3
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR EXCESSIVE RESISTANCE IN THE (K21) IAT SENSOR SIGNAL CIRCUIT
NOTE:
The Intake Air Temperature Sensor is integrated within the MAP sensor.
1. Turn the ignition off.
2. Disconnect the MAP Sensor harness connector.
3. Disconnect the PCM C2 harness connector.
4. Measure the resistance of the (K21) IAT Sensor Signal circuit between the MAP Sensor harness connector and the PCM C2 harness connector.
5. Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (K21) IAT Sensor Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR EXCESSIVE RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
1. Measure the resistance of the (K900) Sensor Ground circuit between the MAP Sensor harness connector and the PCM C2 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the (K900) Sensor Ground circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE (PCM)
1. Reconnect the PCM C2 harness connector.
2. Turn the ignition on.
3. With the scan tool, read the IAT Sensor voltage reading with the MAP Sensor harness connector unplugged.
4. Connector a jumper between the (K21) IAT Sensor Signal circuit and the (K900) Sensor Ground circuit.
5. With the scan tool, read the IAT Sensor voltage reading with the jumper in place.
  Was the voltage reading 5.0 volts with the sensor unplugged and 0 volts with the jumper in place?
  
  Yes
  - Replace the MAP Sensor in accordance with the service information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Replace and program the Powertrain Control Module in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .