Pinpoint Test Y: The Grade Assist Indicator Is Never/Always On

Instrumentation, Message Center and Warning Chimes

Pinpoint Test Y: The Grade Assist Indicator Is Never/Always On

Normal Operation

The Instrument Panel Cluster (IPC) receives the grade assist on/off status from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. When the grade assist function is selected off, the PCM sends a message to the IPC (Instrument Panel Cluster) to illuminate the grade assist indicator.

If the grade assist on/off message is missing for less than 5 seconds, the grade assist indicator remains in the last state (on or off) based upon the last good known message. If the grade assist on/off message is missing for more than 5 seconds, the IPC (Instrument Panel Cluster) sets DTC U0100:00 in continuous memory and defaults the grade assist indicator off.

NOTE: If DTC U0100:00 is set in the IPC (Instrument Panel Cluster), other observable symptoms may be an inoperative speedometer, tachometer or odometer.

This pinpoint test is intended to diagnose the following:

- Grade assist system concern

- Transaxle concern

- PCM

- IPC (Instrument Panel Cluster)

PINPOINT TEST Y : THE GRADE ASSIST INDICATOR IS NEVER/ALWAYS ON

Y1 CHECK THE OPERATION OF THE GRADE ASSIST FUNCTION

- Verify that the grade assist function operates when engaged and turns off when disengaged.

Does the grade assist function operate correctly?

Yes
GO to Y2.

No
REFER to Automatic Transmission/Transaxle.

Y2 CARRY OUT THE IPC (Instrument Panel Cluster) GRADE ASSIST INDICATOR ACTIVE COMMAND USING THE SCAN TOOL

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: IPC (Instrument Panel Cluster) DataLogger.

- Select the IPC (Instrument Panel Cluster) grade assist indicator (TRAILER_LMP) active command. Command the grade assist indicator on and off while observing the grade assist indicator.

Does the grade assist indicator illuminate when commanded on, and turn off when commanded off?

Yes
GO to Y3.

No
INSTALL a new IPC (Instrument Panel Cluster). REFER to Instrument Panel Cluster (IPC) . TEST the system for normal operation.

Y3 RETRIEVE THE RECORDED DTCs FROM THE IPC (Instrument Panel Cluster) SELF-TEST

- Check for recorded DTCs from the IPC (Instrument Panel Cluster) self-test.

Is DTC U0100:00 recorded?

Yes
GO to Pinpoint Test AR. Pinpoint Test AR: DTC U0100:00

No
GO to Y4.

Y4 RETRIEVE THE RECORDED DTCs FROM THE PCM KOEO (Key ON Engine OFF) SELF-TEST

- Check for recorded PCM DTCs from the Key ON Engine OFF (KOEO) self-test.

Are any DTCs recorded?

Yes
REFER to Computers and Control Systems Information.

No
INSTALL a new PCM. TEST the system for normal operation.