P2112-ELECTRONIC THROTTLE CONTROL - UNABLE TO OPEN
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
Ignition on and battery voltage greater than 10 volts.
- Set Condition:
Just after key on, the throttle is opened and closed to test the system. If the TP Sensor does not return to Limp Home Position at the end of this test, this DTC will set. One trip fault and the code will set within 5 seconds. ETC light is flashing.
| Possible Causes |
| THROTTLE PLATE STUCK AT OR BELOW LIMP HOME POSITION |
| (K126) ETC NEGATIVE CIRCUIT SHORTED TO BATTERY VOLTAGE |
| (K124) ETC POSITIVE CIRCUIT OPEN |
| (K126) ETC NEGATIVE CIRCUIT OPEN |
| (K124) ETC POSITIVE CIRCUIT SHORTED TO GROUND |
| (K126) ETC NEGATIVE CIRCUIT SHORTED TO GROUND |
| PCM |
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING).
Diagnostic Test
1. ACTIVE DTCIgnition on, engine not running.
NOTE: The PCM tests the ETC Motor by opening and closing the Throttle Plate before starting the engine. If during this test the Throttle plate does not return to the closed position this DTC sets.
With a scan tool, select View DTCs.
NOTE: Diagnose any TP Sensor, Battery Voltage, and 5-Volt Supply DTCs before continuing.
Is the DTC Active at this time?
Yes
- Go To 2
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2. THROTTLE PLATE STUCK OPEN
Turn the ignition off.
NOTE: The PCM tests the ETC Motor by opening and closing the Throttle Plate before starting the engine. If during this test the Throttle plate does not open this DTC sets.
Remove the Air Cleaner Assembly from the Throttle Body.
Check for any signs of a foreign material causing the Throttle to remain open.
Using a scan tool actuate the ETC Motor.
Does the Throttle Plate move?
Yes
- Go To 3
No
- Remove the debris if possible or replace the Throttle Body Assembly. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
3. (K126) ETC NEGATIVE CIRCUIT SHORTED TO BATTERY VOLTAGE
Turn the ignition off.
Disconnect the Throttle Body harness connector.
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 Miller Special Tool #8815 to perform diagnosis.
Ignition on, engine not running.
With a 12-volt test light connected to ground, probe the (K126) ETC Negative circuit at the appropriate terminal of special tool #8815.
Does the test light illuminate brightly?
Yes
- Repair the short to battery voltage on the (K126) ETC Negative circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 4
4. (K124) ETC POSITIVE CIRCUIT OPEN
Turn the ignition off.
Measure the resistance of the (K124) ETC Positive circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 5
No
- Repair the open in the (K124) ETC Positive circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
5. (K126) ETC NEGATIVE CIRCUIT OPEN
Measure the resistance of the (K126) ETC Negative circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.
Is the resistance below 5.0 ohms?
Yes
- Go To 6
No
- Repair the open in the (K126) ETC Negative circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
6. (K124) ETC POSITIVE CIRCUIT SHORTED TO GROUND
Measure the resistance between a known good ground and the (K124) ETC Positive circuit at the appropriate terminal of special tool #8815.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (K124) ETC Positive circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 7
7. (K126) ETC NEGATIVE CIRCUIT SHORTED TO GROUND
Measure the resistance between a known good ground and the (K126) ETC Negative circuit at the appropriate terminal of special tool #8815.
Is the resistance below 100 ohms?
Yes
- Repair the short to ground in the (K126) ETC Negative circuit.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
- Go To 8
8. 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?
Yes
- 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)