Page 953 of 5267

When Monitored:
With the ignition on and battery voltage greater than 10.4 volts.
Set Condition:
When the Inlet Air Temp Sensor Signal circuit voltage is less than 0.8 of a volt.
Possible Causes
(K21) IAT SIGNAL CIRCUIT SHORTED TO GROUND
(K21) IAT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
INTAKE AIR TEMPERATURE SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.IAT SENSOR VOLTAGE BELOW 0.078 OF A VOLT
Ignition on, engine not running.
With a scan tool, read the IAT voltage.
Is the voltage below 0.078 of a volt?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
2.IAT SENSOR
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 0.05 of a volt?
Ye s>>
Replace the Intake Air Temperature Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
Page 954 of 5267
3.(K21) IAT SIGNAL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C2 PCM harness connector.
Measure the resistance between ground and the (K21) IAT Signal circuit
in the IAT Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short to ground in the (K21) IAT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K21) IAT SIGNAL CIRCUIT SHORTED TO THE (K900) SENSOR GROUND CIRCUIT
Measure the resistance between the (K21) IAT Signal circuit and the
(K900) Sensor ground circuit in the IAT Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the (K900) Sensor ground circuit
and the (K21) IAT Sensor Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
Page 955 of 5267
5.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?
Ye s>>
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)
Page 956 of 5267
P0113-INTAKE AIR TEMPERATURE SENSOR CIRCUIT HIGH
For a complete wiring diagramRefer to Section 8W.
Page 957 of 5267

When Monitored:
With the ignition on. Battery voltage greater than 10.4 volts.
Set Condition:
The Intake Air Temperature (IAT) sensor circuit voltage at the PCM goes above 4.98 volts for 2.8 seconds.
One Trip Fault. Three good trips to turn off the MIL.
Possible Causes
(K21) IAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
(K21) IAT SIGNAL CIRCUIT OPEN
(K900) SENSOR GROUND CIRCUIT OPEN
IAT SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.IAT SENSOR VOLTAGE ABOVE 4.98 VOLTS
Ignition on, engine not running.
With a scan tool, read the Intake Air Temperature Sensor voltage.
Is the voltage above 4.98 volts?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2.IAT SENSOR
Turn the ignition off.
Disconnect the Intake Air Temperature Sensor harness connector.
Connect a jumper wire between the (K21) IAT Signal circuit and the
(K900) Sensor ground circuit in the IAT Sensor harness connector.
Ignition on, engine not running.
With a scan tool, read the IAT Sensor voltage.
Is the voltage below 1.0 volt with the jumper wire installed?
Ye s>>
Replace the IAT Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 3
NOTE: Remove the jumper wire before continuing.
Page 958 of 5267

3.(K21) IAT SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Disconnect the C2 PCM harness connector.
Ignition on, engine not running.
Measure the voltage on the (K21) IAT Signal circuit in the IAT Sensor
harness connector.
Is the voltage above 0 volts?
Ye s>>
Repair the short to battery voltage in the (K21) IAT Signal
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K21) IAT SIGNAL CIRCUIT OPEN
Turn the ignition off.
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 (K21) IAT Signal circuit from the IAT Sen-
sor harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 5
No>>
Repair the open in the (K21) IAT Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 959 of 5267
5.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the
IAT Sensor harness connector to the appropriate terminal of special tool
#8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 6
No>>
Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.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?
Ye s>>
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)
Page 960 of 5267
P0117-ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT LOW
For a complete wiring diagramRefer to Section 8W.