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

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/APP 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 con-
troller 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

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/APP DTCs present?

Yes

>> Refer to the Driveability category and perform the appropriate diagnostic procedure.

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

>> Go To 2

CHECK TO SEE IF DTC IS CURRENT

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

With the scan tool, erase Transmission DTCs.

NOTE: To erase DTC 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 DTC EVENT DATA.

With the scan tool, read Transmission DTCs.

Does this DTC reset?

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 the PCM per the Service Information. With the scan tool PERFORM QUICK LEARN,
then program Pinion Factor in the Front Control Module. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/POWERTRAIN CONTROL MODULE - REMOVAL)

Perform 42RLE TRANSMISSION VERIFICATION TEST - VER 1. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

>> Go To 3

21 - 464

AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

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 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. (Refer to 21 - TRANSMISSION/
TRANSAXLE/AUTOMATIC - 42RLE - STANDARD PROCEDURE)

>> Test Complete.

AUTOMATIC TRANSMISSION 42RLE - ELECTRICAL DIAGNOSTICS

21 - 465

Content .. 1980 1981 1982 1983 ..