Diagnostic Test
- ACTIVE DTC NOTE:
The most likely cause of this DTC is a plugged intake air system or dirty Throttle Body. Check for any TSBs before continuing.
NOTE:Diagnose any 5-Volt Supply, TPS, Oxygen Sensor, Fuel related or MAP Sensor DTCs before continuing.
NOTE:The throttle plate should be free from binding and carbon build up.
NOTE:Question the customer about weather conditions, as ice build up on the throttle blade can cause this fault when the ambient air temperature is in the -10°C (14°F) to 4°C (39°F) range.
- Ignition on, engine not running.
- With a scan tool, read the active DTCs.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
- RESTRICTED AIR INLET SYSTEM
- Turn the ignition off.
- Remove the Air Cleaner Assembly.
- Remove the Air Filter.
- Inspect the Throttle Body opening for signs of any foreign materials.
- Check the intake tube and air cleaner for obstructions; include snow packing questions to customer.
Were any restrictions found?
Yes
- Repair the restriction as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 3
- MAP SENSOR OPERATION
- TPS OPERATION
- Ignition on, engine not running.
- With a scan tool, perform the Throttle Follower Test.
- TPS 1 should start at approximately 0.7 volts and increase to 4.3 volts.
- TPS 2 should start at approximately 4.3 volts and decrease to 0.7 volts.
Is the voltage transition smooth between the appropriate values?
Yes
- Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
No
- Go To 5
- RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT
- Turn the ignition off.
- Disconnect the Throttle Body harness connector.
- Disconnect the PCM C2 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 the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (F855) 5-Volt Supply circuit between the Throttle Body harness connector and the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 6
No
- Repair the excessive resistance in the (F855) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK THE (F855) 5-VOLT SUPPLY CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and (F855) 5-Volt Supply circuit at the Throttle Body harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 7
No
- Repair the (F855) 5-Volt Supply circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between ground and (F855) 5-Volt Supply circuit at the Throttle Body harness connector.
- THROTTLE POSITION SENSOR
- Connect the PCM harness connector.
- Ignition on, engine not running.
- With a scan tool, monitor the TPS voltage.
- Connect a jumper between the (K22) TPS 1 Signal circuit and the (K922) TPS Return circuit in the Throttle Body harness connector.
- TPS 1 voltage should start at approximately 4.7 volts and decrease to 0.3 volts.
- Connect a jumper wire between the (K122) TPS 2 Signal circuit and the (F855) 5-Volt Supply circuit in the Throttle Body harness connector.
- TPS 2 voltage should start at approximately 0.3 volts and increase to 4.7 volts.
Does the TPS voltage change to the appropriate voltage with the jumper installed?
Yes
- Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. Disconnect the Battery before replacing the Throttle Body Assembly. If OK, replace the Throttle Body Assembly. Refer to THROTTLE BODY, REMOVAL . After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 8
- CHECK FOR HIGH RESISTANCE IN THE (K22) TPS 1 SIGNAL CIRCUIT
- Turn the ignition off.
- Disconnect the PCM C2 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 the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (K22) TPS 1 Signal circuit between the Throttle Body harness connector and the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 9
No
- Repair the excessive resistance in the (K22) TPS 1 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK FOR HIGH RESISTANCE IN THE (K122) TPS 2 SIGNAL CIRCUIT
- Measure the resistance of the (K122) TPS Signal circuit between the Throttle Body harness connector and the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 10
No
- Repair the excessive resistance in the (K122) TPS 2 Signal circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance of the (K122) TPS Signal circuit between the Throttle Body harness connector and the GPEC Adaptor.
- CHECK THE (K22) TPS 2 SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and the (K22) TPS 1 Signal circuit at the Throttle Body harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 11
No
- Repair the (K22) TPS 1 Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between ground and the (K22) TPS 1 Signal circuit at the Throttle Body harness connector.
- CHECK THE (K122) TPS 2 SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and the (K122) TPS 2 Signal circuit at the Throttle Body harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 12
No
- Repair the (K122) TPS 2 Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between ground and the (K122) TPS 2 Signal circuit at the Throttle Body harness connector.
- CHECK FOR HIGH RESISTANCE IN THE (K922) TPS RETURN CIRCUIT
- Measure the resistance of the (K922) TPS Return circuit between the Throttle Body harness connector and the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 19
No
- Repair the excessive resistance in the (K922) TPS Return circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance of the (K922) TPS Return circuit between the Throttle Body harness connector and the GPEC Adaptor.
- CHECK FOR HIGH RESISTANCE IN THE (F856) 5-VOLT SUPPLY CIRCUIT
- Turn the ignition off.
- Disconnect the MAP Sensor harness connector.
- Disconnect the PCM C2 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 the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (F856) 5-Volt Supply circuit from the MAP Sensor harness connector to the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 14
No
- Repair the excessive resistance in the (F856) 5-Volt Supply circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- (F856) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND
- Measure the resistance between ground and the (F856) 5-Volt Supply circuit in the MAP Sensor harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 15
No
- Repair the (F856) 5-Volt Supply circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between ground and the (F856) 5-Volt Supply circuit in the MAP Sensor harness connector.
- MAP SENSOR
- Reconnect the PCM C2 harness connector.
- Ignition on, engine not running.
- With a scan tool, monitor the MAP Sensor voltage.
- Connect a jumper between the (K1) MAP Signal circuit and the (K900) Sensor ground circuit.
- Cycle the ignition switch from off to on.
- With a scan tool, monitor the MAP Sensor voltage.
Does the scan tool display MAP voltage from approximately 4.9 volts to below 0.5 volts with the jumper installed?
Yes
- Verify that there is good pin to terminal contact in the MAP Sensor and Powertrain Control Module connectors. If OK, replace the MAP Sensor. Refer to SENSOR, MANIFOLD AIR PRESSURE (MAP), REMOVAL .
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
No
- Go To 16NOTE:
Remove the jumper before continuing.
- CHECK FOR HIGH RESISTANCE IN THE (K1) MAP SIGNAL CIRCUIT
- Turn the ignition off.
- 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 the GPEC Diagnostic Adaptor to perform the diagnosis.
- Connect the (special tool #10436, Adapter, GPEC Diagnostic).
- Measure the resistance of the (K1) MAP Signal circuit from the MAP Sensor harness connector to the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 17
No
- Repair the excessive resistance in the (K1) MAP Signal circuit
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- CHECK THE (K1) MAP SIGNAL CIRCUIT FOR A SHORT TO GROUND
- Measure the resistance between ground and the (K1) MAP Signal circuit in the MAP Sensor harness connector.
Is the resistance above 10k Ohms?
Yes
- Go To 18
No
- Repair the (K1) MAP Signal circuit for a short to ground.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance between ground and the (K1) MAP Signal circuit in the MAP Sensor harness connector.
- CHECK FOR HIGH RESISTANCE IN THE (K900) SENSOR GROUND CIRCUIT
- Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor harness connector to the GPEC Adaptor.
Is the resistance below 5.0 Ohms?
Yes
- Go To 19
No
- Repair the excessive resistance in the (K900) Sensor ground circuit.
- Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
- Measure the resistance of the (K900) Sensor ground circuit from the MAP Sensor harness connector to the GPEC Adaptor.
- POWERTRAIN CONTROL MODULE (PCM)
- Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the MAP Sensor, Throttle Body, and the Powertrain Control Module (PCM).
- Look for any chafed, pierced, pinched, or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the MAP Sensor, Throttle Body, and Powertrain Control Module connectors.
- Perform any Technical Service Bulletins that may apply.
Were there any problems found?
Yes
- Repair as necessary.
- 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 .