Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 21 - TRANSMIS-
SION/TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

Theory of Operation

The powertrain controller receives the throttle position signal from the Throttle Position Sensor (TPS). 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.

Diagnostic Test

DETERMINING 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 the Driveability category and perform the appropriate diagnostic procedure.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

>> Go To 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.

Does this DTC reset?

Yes

>> Go To 3

>> Go To 4

AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

21 - 3

P0122-TPS/APP CIRCUIT LOW (CONTINUED)

POWERTRAIN CONTROL MODULE

NOTE: Due to the integration of the Powertrain and Transmission Control Modules, bus 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.

Verify the flash level of the controller and update the controller if available.

With the scan tool, check the EATX DTC EVENT DATA to help identify the conditions in which the DTC was set.

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, then program Pinion Factor in the Front Control Module.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1.

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 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.

>> Test Complete.

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AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

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