Transmission Code
P0123-TPS/APP CIRCUIT HIGHWhen 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 Pre-Diagnostic Troubleshooting procedure before proceeding.
Theory of Operation
The powertrain controller receives the throttle position signal and its ground from the Throttle Position Sensor (TPS). The TPS has a 5 volt pull up. The throttle signal is checked for out of range as well as intermittent operation (excessive signal changes). The engine controller transmits the throttle value via the Bus. Most engine controllers can synthesize the throttle value if the throttle position sensor signal is lost. If a throttle error is detected by the transmission control system and the throttle value is available via the Bus. The Bus throttle value will be used and normal operation will continue, however a throttle fault code will be set. If a throttle error is detected and the throttle value is not available via the Bus, normal operation will be discontinued, a throttle fault code will be set, and the MIL will be turned on after 5 min. of substituted operation.
Diagnostic Test
1. DETERMINING IF RELATED ENGINE TPS DTC'S ARE PRESENT
With the scan tool, check Engine DTC's, this includes all one trip failures.
Are there any Engine TPS DTCs present?
Yes >>Refer to the Driveability category and perform the appropriate symptom.
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 DTCs.
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 DTCs.
Did the DTC P0123 THROTTLE POSITION SENSOR HIGH, reset?
Yes >>Go To 3
No >>Go To 4
3. POWERTRAIN CONTROL MODULE
Note: Due to the integration of the Powertrain and Transmission Control Modules, communication between the modules is internal.
Using the schematics as a guide, inspect the wiring and connectors. Repair as necessary. Pay particular attention to all power and ground circuits.
If there are no possible causes remaining, view repair.
Repair
Replace the Powertrain Control Module per the Service Information. WITH THE scan tool PERFORM QUICK LEARN.
Perform 42RLE TRANSMISSION VERIFICATION TEST -VER 1.
4. 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 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 >>Repair as necessary.
Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.
No >>Test Complete.