Diagnostic Test

WARNING: This page is about a different car, the 2013 RAM 1500. However, it is still accessible from the selected car via links, so may be relevant.

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

NOTE:
Make sure the throttle is fully closed and free from binding or carbon build up.

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 blade moves freely and does not hang up near Wide Open Throttle before trying to repair P0123.
1. Turn the ignition on.
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.
  
  NOTE:
  If the P2123-APP Sensor 1 Circuit High DTC is also Active, diagnose the P2123 before continuing with the P0123 diagnostic procedure.
  
  Is the DTC Active at this time?
  
  Yes
  - Go To 2
  No
  - Go To 8
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 at the Throttle Body harness connector.
  Is the voltage reading above 5.2 volts?
  
  Yes
  - Repair the (K22) TPS 1 Signal circuit for a short to voltage.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 3
CHECK THE (K22) TPS 1 SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. 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.
3. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
4. Measure the resistance of the (K22) TPS 1 Signal circuit from the Throttle Body harness connector to the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 4
  No
  - Repair the (K22) TPS 1 Signal circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK FOR THE (K22) TPS 1 SIGNAL CIRCUIT SHORTED TO THE (F855) 5-VOLT SUPPLY CIRCUIT
1. Measure the resistance between the (K22) TPS 1 Signal circuit and the (F855) 5-Volt Supply circuit in the Throttle Body harness connector.
  Is the resistance above 10k Ohms?
  
  Yes
  - Go To 5
  No
  - Repair the short between the (F855) 5-Volt Supply circuit and the (K22) TPS 1 Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
CHECK THE (K922) TPS RETURN CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (K922) TPS Return circuit from the Throttle Body harness connector to the GPEC Adaptor.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Go To 6
  No
  - Repair the (K922) TPS Return circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
THROTTLE POSITION SENSOR
1. Turn the ignition off.
2. Reconnect the PCM C2 harness connector.
3. Turn the ignition on, engine not running.
4. Connect a jumper between the (K22) TPS 1 Signal circuit and the (K922) TPS Return circuit at the Throttle Body harness connector.
5. With the scan tool, view DTCs.
  NOTE:
  The scan tool should display a P0122-THROTTLE POSITION SENSOR 1 CIRCUIT LOW DTC as active or pending with the jumper in place.
  
  Does the scan tool display the DTC 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. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, using a scan tool select the ETC RELEARN function. Refer to THROTTLE BODY, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 7
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 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 STANDARD PROCEDURE .
  No
  - Replace and program the Powertrain Control Module (PCM) in accordance with the service information. Refer to MODULE, POWERTRAIN CONTROL, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
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 STANDARD PROCEDURE .
  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. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, using a scan tool select the ETC RELEARN function. Refer to THROTTLE BODY, REMOVAL .
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .