Powertrain Control Module (PCM) - 545RFE
P0122-TPS/APP CIRCUIT LOW
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The three wire (Throttle Position Sensor (TPS) provides the Powertrain Control Module (PCM) with an input signal voltage that represents the throttle blade position of the throttle body. The Throttle Position Sensor (TPS) is connected to the throttle blade shaft. As the position of the throttle blade changes, the output voltage of the TPS changes.
The PCM supplies approximately 5.0 volts to the TPS. The TPS output voltage (input signal to the PCM) represents the throttle blade position. The PCM receives an input signal voltage from the TPS. This will vary in an approximate range from 0.26 of a volt at minimum throttle opening (idle), to 4.49 volts at maximum opening (wide open throttle).
The Accelerator Pedal Position Sensor (APPS) is a linear potentiometer. It provides the PCM/ECM with a voltage signal proportional to the angle, or position of the accelerator pedal. The APPS signal along with inputs from other sensors is used by the PCM/ECM to calculate the throttle plate position.
- When Monitored:
Continuously with the ignition on and engine running.
- Set Condition:
This DTC will set if the monitored TPS voltage drops below.078 of a volt for the period of 0.48 of a second.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. CHECK IF RELATED ENGINE TPS/APPS DTCs ARE PRESENT
1. With the scan tool, read Engine DTCs.
Are there any Engine TPS/APPS DTCs present?
Yes
- Testing and Inspection Perform the appropriate diagnostic procedure.
No
- Go To 2
2. CHECK IF THE DTC IS CURRENT
1. With the scan tool, record the Event Data to help identify the conditions in which the DTC was set.
2. With the scan tool, erase PCM DTCs and the Event Data.
NOTE: Clearing DTCs does NOT erase the Event Data. To erase the Event Data you must either perform a Quick Learn procedure or battery disconnect (if available) with the scan tool, or manually disconnect the battery. Whatever method used might reset certain learned transmission values to controller defaults and may cause poor shift quality until those values are relearned.
3. Using the Event Data recorded earlier, test drive the vehicle while trying to duplicate the operating conditions in which the DTC originally set.
4. With the scan tool, read DTCs.
Did this DTC reset during the road test?
Yes
- Using the schematics as a guide, check the Powertrain Control Module (PCM) terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. If no problems are found, replace and program the PCM. With the scan tool, perform Quick Learn. TCM Quick Learn
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. 545RFE Transmission Verification Test
No
- Go To 3
3. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle the wiring and connectors while checking for shorted and open circuits.
4. With the scan tool, check the Event Data to help identify the conditions in which the DTC was set.
Were there any problems found?
Yes
- Repair as necessary.
- Perform the 545RFE TRANSMISSION VERIFICATION TEST. 545RFE Transmission Verification Test
No
- Test Complete.