Transmission Code

P0123-TPS/APP CIRCUIT HIGH
- When Monitored:
Continuously with the ignition on and engine running.
- Set Condition:
This DTC will set if the monitored TPS voltage rises above 4.94 volts for the period of 0.48 seconds.

Possible Causes
- RELATED TPS ENGINE DTC's PRESENT
- POWERTRAIN CONTROL MODULE

Always perform the 42RLE Pre-Diagnostic Troubleshooting Procedure before proceeding. Component Tests and General Diagnostics

Theory of Operation
The powertrain controller receives the throttle position signal from the Throttle Position Sensor (TPS)/ Accelerator Pedal Position (APP). The controller provides the TPS with a 5 volt pull up and a sensor ground. The signal is checked for being out of range as well as for intermittent operation (excessive signal changes). The engine controller transmits the throttle value onto the Bus. Most engine controllers will calculate the throttle value if the throttle signal is lost. If an error is detected by the transmission controller and the throttle value is available on the Bus, the Bus value will be used, normal operation will continue, and a TPS/APP code will be set. If an error is detected and the throttle value is not available on the Bus, normal operation will be discontinued, a TPS/APP DTC will be set, and the MIL will be turned on after 5 minutes of calculated operation.

Diagnostic Test
1. DETERMINING IF RELATED ENGINE TPS DTC's ARE PRESENT
With the scan tool, check Engine DTC's, including pending DTC's and one trip failures.
Are there any Engine TPS/APP DTC's present?
YES >>Refer to the Driveability category and perform the appropriate diagnostic procedure.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests
NO >>Go To 2

2. CHECK TO SEE IF DTC IS CURRENT
With the scan tool, record the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set. With the scan tool, erase Transmission DTC's.

NOTE: To erase EATX EVENT DATA information, a BATTERY DISCONNECT must be performed. Performing a BATTERY DISCONNECT will reset all learned Transmission values to controller defaults which may lead to erratic shift schedules.

Drive the vehicle and try to duplicate the conditions in which the DTC was reported by the EATX DTC EVENT DATA.
With the scan tool, read Transmission DTC's.
Does this DTC reset?
YES >>Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests
NO >>Go To 3

3. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
Wiggle the wires while checking for shorted and open circuits. Pay particular attention to the TPS/APP signal and sensor ground circuits.
With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.
Were there any problems found?
YES >>Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. Verification Tests
NO >>Test Complete.