Pinpoint Tests AJ: A Hill Descent Control Message Is Inoperative/Always On (Raptor Only)

Instrumentation, Message Center and Warning Chimes

Pinpoint Tests

Pinpoint Test AJ: A Hill Descent Control Message Is Inoperative/Always On (Raptor Only)

Normal Operation

The hill descent control system maintains vehicle speed on a downhill grade at operating speeds between 3 km/h (2 mph) and 32 km/h (20 mph). The system goes into standby mode on a flat or uphill terrain. The system deactivates at speeds above 64 km/h (40 mph). During periods of sustained use, the hill descent control system may automatically deactivate in order to cool the braking system.

When the hill descent control switch is pressed, a ground signal is sent to the PCM. The PCM then sends a message to the ABS module along the High Speed Controller Area Network (HS-CAN) requesting system activation. The ABS module uses inputs from the Restraints Control Module (RCM) and wheel speed sensors to determine the mode of operation.

The Instrument Panel Cluster (IPC) receives the hill descent control status from the ABS module over the HS-CAN. The message center also displays hill descent control messages to inform the driver they have entered or exited various states of the hill descent control function.

If the hill descent message is missing for less than 5 seconds, the hill descent active message center indicator remains in the last state (on or off) based on the last status message received. If the hill descent status message is missing for more than 5 seconds, the IPC sets DTC U0121:00 and defaults the hill descent active message center indicator off.

This pinpoint test is intended to diagnose the following:

- Message center concern
- ABS module

PINPOINT TEST AJ: A HILL DESCENT CONTROL MESSAGE IS INOPERATIVE/ALWAYS ON (RAPTOR ONLY)

-------------------------------------------------
AJ1 VERIFY THE OPERATION OF THE DOOR AJAR MESSAGE CENTER WARNING INDICATOR

- Close all doors then open the LH front door.
- Ignition ON.

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

- Observe the message center.
- Does the message center display DRIVER DOOR AJAR?

Yes
GO to AJ2.

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

-------------------------------------------------
AJ2 CHECK AND ENSURE THE HILL DESCENT CONTROL MODE FUNCTIONS

- Start the engine.
- Drive the vehicle between 3 km/h (2 mph) and 32 km/h (20 mph) on a downhill grade and activate the hill descent control system mode.
- Are the brakes applying on a downhill grade?

Yes
GO to AJ3.

No
REFER to Vehicle Dynamic Systems Testing and Inspection.

-------------------------------------------------
AJ3 RETRIEVE THE RECORDED DTCs FROM THE IPC SELF-TEST

- Check for recorded DTCs from the IPC self-test.
- Is DTC U0121:00 recorded?

Yes
GO to Pinpoint Test AV. Pinpoint Tests AV: DTC U0121:00

No
GO to AJ4.

-------------------------------------------------
AJ4 RETRIEVE THE RECORDED DTCs FROM THE ABS MODULE SELF-TEST

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

Yes
REFER to Vehicle Dynamic Systems Testing and Inspection.

No
INSTALL a new ABS module. REFER to Vehicle Dynamic Systems Service and Repair.

-------------------------------------------------