Pinpoint Tests AC: The Tow Haul Message Center Indicator Is Never/Always On

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test AC: The Tow Haul Message Center Indicator Is Never/Always On

Normal Operation

The tow haul indicator illuminates when the tow haul system has been engaged and is actively providing tow haul control for the vehicle. The Instrument Panel Cluster (IPC) receives the O/D off and tow haul indicator request from the PCM over the High Speed Controller Area Network (HS-CAN).

If the tow haul indicator request message is missing or invalid for less than 5 seconds, the tow haul indicator remains in the last state (on or off), based upon the last known good message received. If the or tow haul indicator request message is missing for more than 5 seconds, the IPC sets DTC U0101:00 in continuous memory and defaults the tow haul indicator off.

This pinpoint test is intended to diagnose the following:

- Message center concern
- PCM

PINPOINT TEST AC: THE TOW HAUL MESSAGE CENTER INDICATOR IS NEVER/ALWAYS ON

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AC1 VERIFY THE OPERATION OF THE DOOR AJAR MESSAGE CENTER WARNING INDICATOR

- Close all doors then open the LH front door.

- NOTE: If multiple warnings are present, the message center cycles through each of the warnings. Allow the displays to cycle through each display while determining whether the door ajar message center warning indicator is active.

- Observe the message center.
- Is the door ajar message center warning indicator active?

Yes
GO to AC2.

No
GO to Pinpoint Test AF. Pinpoint Tests AF: The Message Center Is Not Operating Correctly

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AC2 RETRIEVE AND RECORD THE IPC DTCs FROM THE SELF-TEST

- Check for recorded IPC DTCs from the self-test.
- Are any DTCs recorded?

Yes
For DTC U0100:00, GO to Pinpoint Test AT Pinpoint Tests AT: DTC U0100:00. For all other DTCs, REFER to DTC Charts. Instrumentation, Message Center and Warning Chimes

No
GO to AC3.

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AC3 RETRIEVE AND RECORD THE DTCs FROM THE PCM KOEO 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.

No
GO to AC4.

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AC4 VERIFY THE OPERATION OF THE TOW HAUL SYSTEM

- Verify the tow haul system turns off when turned off and turns on when turned on.
- Does the tow haul system function correctly?

Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair. TEST the system for normal operation.

No
REFER to Automatic Transaxle/Transmission External Controls Testing and Inspection.

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