Diagnostic Test

ACTIVE DIAGNOSTIC TROUBLE CODE (DTC)
NOTE:
When this DTC is Active the engine speed, torque and vehicle speed are limited to a Limp in mode.

NOTE:
If a 5-Volt Supply DTC has also set, diagnose the 5-Volt DTC before continuing.

NOTE:
If P2101 is also set, then make sure that the throttle blade is fully closed and free from binding or carbon build up before trying to repair P0123.
1. Start the engine and allow it to idle.
2. With the scan tool, read the active DTCs.
  NOTE:
  If the DTC does not reset it may be necessary to test drive the vehicle.
  
  Is the DTC Active at this time?
  
  Yes
  - Go To 2
  No
  - Go To 7
CHECK THE (K22) TPS 1 SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE
1. Turn the ignition off.
2. Disconnect the Throttle Body harness connector.
3. Turn the ignition on.
4. Measure the voltage on the (K22) TPS 1 Signal circuit in the Throttle Body harness connector.
  Does the voltage measure above 5.2 volts?
  
  Yes
  - Repair the (K22) TPS 1 Signal circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 3
CHECK FOR A SHORT BETWEEN THE (K22) TPS 1 SIGNAL CIRCUIT AND THE 5-VOLT SUPPLY CIRCUIT
1. Turn the ignition off.
2. Disconnect the PCM C2 harness connector.
3. Measure the resistance between the (K22) TPS 1 Signal circuit and the 5-Volt Supply circuit in the Throttle Body harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the short between the (K22) TPS 1 Signal circuit and the 5-Volt Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K922) TPS RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K922) TPS Return circuit between the Throttle Body harness connector and the PCM C2 harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the open in the (K922) TPS Return circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
THROTTLE POSITION SENSOR
1. Turn the ignition off.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on.
4. With the scan tool, monitor the TPS 1 voltage.
5. Connect a jumper between the (K22) TPS 1 Signal circuit and the (K922) TPS Return circuit at the Throttle Body harness connector.
  NOTE:
  The sensor voltage should be approximately 0.0 volts (plus or minus 0.1 volts) with the jumper in place.
  
  Does the scan tool display the voltage as described above?
  
  Yes
  - Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. If OK, replace the Throttle Body Assembly. Refer to THROTTLE BODY, REMOVAL . Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, using a scan tool select the ETC RELEARN function.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 6
    NOTE:
    Remove the jumper wire before continuing.
POWERTRAIN CONTROL MODULE (PCM)
1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM).
2. Look for any chafed, pierced, pinched or partially broken wires.
3. Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module harness connectors.
4. 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 .
THROTTLE FOLLOWER TEST
1. With the scan tool, perform the ETC Throttle Follower Test.
2. Monitor the TPS 1 voltage.
  Does the voltage start at approximately 0.7 volts and increase to approximately 4.3 volts with a smooth transition?
  
  Yes
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
  No
  - Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. If OK, replace the Throttle Body Assembly. Refer to THROTTLE BODY, REMOVAL . Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, using a scan tool select the ETC RELEARN function.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .