Automatic Transmission 62TE
P0123 - TPS/APP Circuit High
For a complete wiring diagram, refer to.
Theory of Operation
The powertrain controller receives the throttle position signal from the throttle position sensor. 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 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 DTC will be set, and the MIL will be turned on after 5 minutes of calculated operation.
• 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.
Always perform the pre-diagnostic troubleshooting procedure before proceeding. Refer to => Non-DTC Based Diagnostics. Pre-Diagnostic Troubleshooting Procedure
Test Step 1 - Determine If Related Engine TPS DTCs are Present
• With the scan tool, check engine DTCs, including pending DTCs and one trip failures.
Are there any engine TPS DTCs present?
Yes
• Refer to => Engine DTC Based Diagnostics.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 2.
Test Step 2 - Determine if DTC is Current
• With the scan tool, record the event data to help identify the conditions in which the DTC was set.
• With the scan tool, erase any transmission DTCs.
• To erase 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 event data.
• With the scan tool, read transmission DTCs.
Does this DTC reset?
Yes
• Using the schematics as a guide, check the PCM terminals for corrosion, damage, or terminal push out. Pay particular attention to all power and ground circuits. Check for service bulletins for any possible causes that may apply. If no problems are found, replace and program the PCM. With the scan tool, perform Quick Learn.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Go to Test Step 3.
Test Step 3 - Check the 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 signal and sensor ground circuits.
• With the scan tool, check the event data to help identify the conditions in which the DTC was set.
• Check for any service bulletins for any possible causes that may apply.
Were any problems found?
Yes
• Repair as necessary.
• Perform the Transmission Verification Test. Refer to => Non-DTC Based Diagnostics. Transmission Verification Test
No
• Test Complete.