Page 945 of 5267

3.(K1) MAP SIGNAL CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the C1 and C2 PCM harness connectors.
Ignition on, engine not running.
Measure the voltage on the (K1) MAP Signal circuit in the MAP Sensor
harness connector.
Is the voltage above 0 volts?
Ye s>>
Repair the short to battery voltage in the (K1) MAP Signal
circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.(K1) MAP 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 (K1) MAP Signal circuit from the MAP
Sensor 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 (K1) MAP Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 946 of 5267
5.(K1) MAP SIGNAL CIRCUIT SHORTED TO THE (F856) 5-VOLT SUPPLY CIRCUIT
Measure the resistance between the (K1) MAP Signal circuit and the
(F856) 5-volt Supply circuit in the MAP Sensor harness connector.
Istheresistancebelow100ohms?
Ye s>>
Repair the short between the (F856) 5-volt Supply circuit
and the (K1) MAP Signal circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 6
6.(K900) SENSOR GROUND CIRCUIT OPEN
Measure the resistance of the (K900) Sensor ground circuit from the
MAP Sensor harness connector to the appropriate terminal of special
tool #8815.
Is the resistance below 5.0 ohms?
Ye s>>
Go To 7
No>>
Repair the open in the (K900) Sensor ground circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 949 of 5267

When Monitored:
With the ignition on and no Intake Air Temperature Sensor open/shorted faults present.
Set Condition:
After 5 warm cycles have occurred (coolant increases at least 22°C (40°F) to a minimum of 71°C (160°F) and
the odometer mileage has increased 196.6 miles and the Intake Air Temperature has had less than 5°C (9°F)
change in temperature.
Possible Causes
RESISTANCE IN THE (K21) IAT SENSOR SIGNAL CIRCUIT
RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
IAT SENSOR
PCM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING)
1.GOOD TRIP EQUAL TO ZERO
Ignition on, engine not running.
With the scan tool, read DTCs and record the related Freeze Frame data.
Is the Good Trip Counter equal to zero?
Ye s>>
Go To 2
No>>
Refer to the INTERMITTENT CONDITION Diagnostic Procedure. (Refer to 9 - ENGINE - DIAGNOSIS
AND TESTING)
2.IAT SENSOR VOLTAGE ABOVE 4.6 VOLTS
Turn the ignition off.
Disconnect the Intake Air Temperature Sensor harness connector.
Ignition on, engine not running.
With the scan tool, read the IAT voltage.
Is the voltage above 4.6 volts?
Ye s>>
Go To 3
No>>
Go To 5
Page 950 of 5267

3.IAT SENSOR VOLTAGE BELOW 1.0 VOLT
Turn the ignition off.
Connect a jumper wire across the IAT Sensor harness connector.
Ignition on, engine not running.
With the scan tool, read the IAT voltage.
Is the voltage below 1.0 volt?
Ye s>>
Replace the Intake Air Temperature Sensor.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
NOTE: Remove the jumper wire and connect the Sensor harness
connector before continuing.
4.RESISTANCE IN THE (K21) IAT SENSOR SIGNAL CIRCUIT
Turn the ignition off.
NOTE: Make sure the voltmeter leads meet the terminals in the
connector and that there is good terminal to wire connection.
NOTE: Make sure the voltmeter leads are connected for positive
polarity
Backprobe the (K21) IAT Sensor Signal circuit at the IAT Sensor har-
ness connector and PCM harness connector with the voltmeter leads.
Start the engine.
Allow the engine to idle.
Is the voltage below 0.10 of a volt?
Ye s>>
Go To 6
No>>
Repair the excessive resistance in the (K21) IAT Sensor
Signal circuit.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
Page 951 of 5267

5.RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
Turn the ignition off.
NOTE: Make sure the voltmeter leads meet the terminals in the
connector and that there is good terminal to wire connection.
NOTE: Make sure the voltmeter leads are connected for positive
polarity
Backprobe the (K900) Sensor ground circuit at the IAT Sensor harness
connector and PCM harness connector with both leads of a voltmeter.
Start the engine.
Allow the engine to idle.
Is the voltage below 0.10 of a volt?
Ye s>>
Go To 6
No>>
Repair the excessive resistance in the (K900) Sensor
ground circuit.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 -
ENGINE - STANDARD PROCEDURE)
NOTE: Turn the ignition off before continuing.
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.
If there are no possible causes remaining, view repair.
Repair
Replace and program the Powertrain Control Module per Service Information.
Perform POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 952 of 5267
P0112-INTAKE AIR TEMP SENSOR VOLTAGE TOO LOW
For a complete wiring diagramRefer to Section 8W.
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