Page 163 of 5267

P2072-ELECTRONIC THROTTLE CONTROL SYSTEM - ICE BLOCKAGE
For a complete wiring diagramRefer to Section 8W.
When Monitored:
Ignition on.
Set Condition:
The PCM recognizes the Throttle plate is stuck during extremely cold Ambient Temperature operation. The
throttle plate goes through a de-icing procedure. If the throttle blade still doesn’t move this fault sets. The MIL
will not illuminate. The vehicle willbe in Limp home condition, limiting rpm and vehicle speed.
Possible Causes
THROTTLE PLATE FROZEN
Diagnostic Test
1.THROTTLE BODY INSPECTION
Ignition on, engine not running.
With a scan tool, read DTCs and record the related Freeze Frame data.
NOTE: This DTC sets in extreme cold Ambient Temperatures with the throttleplatestuckbythetimethe
vehicle gets to the dealership the condition may be corrected.
NOTE: Diagnose any other DTCs that may also be set before continuing.
Turn the ignition off.
Remove the Air Cleaner Assembly from the Throttle Body.
Check for any signs of a foreign material (ice or dirt) on the Throttle Plateor in the bore causing the Throttle Plate
to stick.
Isthethrottlebladestillstuckbecauseitisfrozen?
Ye s>>
Allow the Throttle Body to thaw naturally in a room temperature climate.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Te s t C o m p l e t e .
Page 173 of 5267
17.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 175 of 5267

When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive as wellas a purge fuel multiplier and the
result is below a certain value for 30 seconds over two trips, a freeze frameis stored, the MIL illuminates and
a trouble code is stored. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
1/2O2SENSOR
(K141) O2 SENSOR 1/2 SIGNAL CIRCUIT
(K299) O2 1/2 HEATER CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 1/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
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.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 176 of 5267

3.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
AIR INDUCTION SYSTEM - must be free from leaks
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connectedtocorrectinjector
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.O2 SENSOR
Ignition on, engine not running.
Disconnect the 1/2 O2 Sensor harness connector.
With the scan tool, monitor the 1/2 O2 Sensor voltage.
The O2 Sensor voltage should read 5.0 volts on the scan tool with the
connector disconnected.
Using a jumper wire, jump the (K141) O2 Sensor 1/2 Signal circuit to
the (K904) O2 Return Downstream circuit in the O2 Sensor harness
connector.
NOTE: The voltage should drop from 5.0 volts to 2.5 volts with the
jumper wire in place.
Did the O2 Sensor volts change from 5.0 volts to 2.5 volts?
Ye s>>
Replace the O2 Sensor
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5
Page 177 of 5267
5.(K141) O2 SENSOR 1/2 SIGNAL CIRCUIT
Remove the jump wire.
Ignition on, engine not running.
With the scan tool, monitor the 1/2 O2 Sensor voltage.
Is the voltage above 4.8 volts?
Ye s>>
Go To 6
No>>
Check the (K141) O2 Sensor 1/2 Signal circuit for an open
or short to voltage. Inspect the O2 Sensor connector and
the PCM harness connector. If OK, replace and program
the Powertrain Control Module per Service Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
6.(K299) O2 SENSOR 1/2 HEATER CONTROL CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the C3 PCM harness connector.
Measure the resistance between ground and the (K299) O2 Sensor 1/2
Heater Control circuit from the O2 Sensor harness connector.
Is the resistance below 5.0 ohms?
Ye s>>
Repair the short to ground in the (K299) O2 Sensor 1/2
Heater Control circuit.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 7
Page 178 of 5267
7.(K904) O2 RETURN DOWNSTREAM CIRCUIT
Measure the voltage on the (K904) O2 Return Downstream circuit in the
O2 Sensor harness connector.
Is the voltage at 2.5 volts?
Ye s>>
Check the fuel system for contaminants.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Check the (K904) O2 Return Downstream circuit for a short
to ground, open, or short to voltage. Inspect the O2 Sensor
connector and the PCM harness connector. If OK, replace
and program the Powertrain Control Module per Service
Information.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
Page 180 of 5267

When Monitored:
With the engine running in closed loop mode, the ambient/battery temperature above (-7°C) 20°F, altitude
below 8500 ft.
Set Condition:
If the PCM multiplies short term compensation by long term adaptive as wellas a purge fuel multiplier and the
result is below a certain value for 30 seconds over two trips, a freeze frameis stored, the MIL illuminates and
a trouble code is stored. Two Trip Fault. Three good trips to turn off the MIL.
Possible Causes
EXHAUST LEAK
ENGINE MECHANICAL
1/2O2SENSOR
(K141) O2 SENSOR 1/2 SIGNAL CIRCUIT
(K299) O2 HEATER 1/2 CONTROL CIRCUIT
(K904) O2 RETURN DOWNSTREAM CIRCUIT
FUEL CONTAMINATION
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE -
DIAGNOSIS AND TESTING).
Diagnostic Test
1.ACTIVE DTC
NOTE: Check the vehicle repair history. If the 1/2 O2 has been replaced makesure that the O2 sensor was
properly installed and meets OEM specification.
NOTE: Check for contaminants that may have damaged the O2 Sensor: contaminated fuel, unapproved sil-
icone, oil and coolant.
Ignition on, engine not running.
With a scan tool, read DTCs.
Is the DTC active at this time?
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.EXHAUST LEAK
Turn the ignition off.
WARNING: To avoid personal injury from the exhaust system being hot, allowthe exhaust to cool down to
a safe temperature before performing a physical inspection. Failure to follow these instructions can result in
personal injury or death.
Visually and Physically inspect the exhaust system for holes, cracks and blockage in the exhaust system.
Is the exhaust system is good condition?
Ye s>>
Go To 3
No>>
Repair or Replace as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
Page 181 of 5267

3.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems
AIR INDUCTION SYSTEM - must be free from leaks.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
FUEL INJECTOR - plugged or restricted injector; control wire not connectedtocorrectinjector
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 4
4.O2 SENSOR
Ignition on, engine not running.
Disconnect the 1/2 O2 Sensor harness connector.
With the scan tool, monitor the 1/2 O2 Sensor voltage.
The O2 Sensor voltage should read 5.0 volts on the scan tool with the
connector disconnected.
Using a jumper wire, jump the (K141) O2 Sensor 1/2 Signal circuit to
the (K904) O2 Return Downstream circuit in the O2 Sensor harness
connector.
NOTE: The voltage should drop from 5.0 volts to 2.5 volts with the
jumper wire in place.
Did the O2 Sensor volts change from 5.0 volts to 2.5 volts?
Ye s>>
Replace the O2 Sensor.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to
9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 5