Pinpoint Test X: The PRNDL Indicator is Never/Always On

Instrumentation, Message Center and Warning Chimes

Pinpoint Test X: The PRNDL Indicator is Never/Always On

Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number

Normal Operation

The Instrument Cluster (IC) receives the transmission range status from the PCM (4R70E/4R75E transmission) or the Transmission Control Module (TCM) (6R80 transmission) over the High Speed Controller Area Network (HS-CAN) communication bus. The IC also uses a park detect switch (part of the brake shift interlock) to signal the IC that the shift lever is fully seated in the PARK position. The IC compares the park detect switch input with the transmission range status sent from the PCM or TCM and looks for vehicle speed above 16 km/h (10 mph). The IC provides a reference voltage to the brake shift interlock on circuit CET52 (GN). When the gearshift is in PARK (P), the brake shift indicator routes the reference voltage to ground, pulling the circuit low to the IC. When the gearshift is moved out of PARK (P), the brake shift interlock opens the ground sending the reference voltage high. If the PRNDL information is missing from the PCM or TCM, the IC sets DTC U0100 (PCM) or DTC U0101 (TCM).

NOTE: If DTC U0100 is set in the IC, other observable symptoms may be an inoperative speedometer, tachometer, temperature gauge or odometer.

- DTC C1945 (Park Switch Indicates Park with Vehicle Moving) - a continuous memory DTC that sets if the IC receives a transmission range input other than PARK (P) and detects a short to ground on the park detect switch input, circuit CET52 (GN), pulling the circuit low with a Vehicle Speed Sensor (VSS) input over 16 km/h (10 mph), indicating that the vehicle is in motion.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Brakeshift interlock
- TCM (6R80 transmission)
- PCM concern (4R70E/4R75E transmission)
- IC



PINPOINT TEST X: THE PRNDL INDICATOR IS NEVER/ALWAYS ON

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

X1-X5:

X5-X6: