Pinpoint Test A: The Forward Collision Warning System Is Inoperative

Forward Collision Warning

Pinpoint Test A: The Forward Collision Warning System Is Inoperative

Refer to Wiring Diagram Set 136, Vehicle Emergency Messaging System for schematic and connector information. Diagrams By Number

Normal Operation

The forward collision warning system is enabled when the ignition switch is in the RUN position. The Smart Junction Box (SJB) sends a serial data ignition state message over the Medium Speed Controller Area Network (MS-CAN) to the Instrument Panel Cluster (IPC). The IPC (Instrument Panel Cluster) then gateways the ignition state message to the HUD (Head Up Display) module over the High Speed Controller Area Network (HS-CAN). The LEDs that are internal to the HUD (Head Up Display) module illuminate for 3 seconds to indicate the system is operational. This is know as the bulb prove-out for the LEDs.

The radar sensor unit, which is integral to the Cruise-Control Module (C-CM), sends out a radar signal to the vehicle in the path of travel and receives the radar signal back to determines the distance and relative speed of that vehicle. The C-CM (Cruise-Control Module) sends a serial data message via the HS-CAN (High Speed Controller Area Network) to the HUD (Head Up Display) module if the vehicle in the path of travel enters the preset gap for a collision warning. The HUD (Head Up Display) module receives a serial data message from the C-CM (Cruise-Control Module) to flash the LEDs. The C-CM (Cruise-Control Module) also sends a serial data message to the IPC (Instrument Panel Cluster) to activate a chime from the IPC (Instrument Panel Cluster) and gateways a message over the MS-CAN (Medium Speed Controller Area Network) to mute the Audio Control Module (ACM) volume. The system can be disabled through the IPC (Instrument Panel Cluster) message center.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- C-CM (Cruise-Control Module)

- HUD (Head Up Display) module

- IPC (Instrument Panel Cluster)

PINPOINT TEST A : THE FORWARD COLLISION WARNING SYSTEM IS INOPERATIVE

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

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.

A1 CHECK THE DTCs FROM THE CONTINUOUS AND ON-DEMAND HUD (Head Up Display) MODULE SELF-TESTS

- Check the HUD (Head Up Display) module DTCs from the continuous and on-demand self-tests.

Are any HUD (Head Up Display) module DTCs recorded?

Yes
REFER to DTC Charts. Forward Collision Warning

No
GO to A2.

A2 CHECK THE C-CM (Cruise-Control Module) DTCs

- Check the C-CM (Cruise-Control Module) DTCs from the continuous and on-demand self-tests.

Are any C-CM (Cruise-Control Module) DTCs recorded?

Yes
REFER to Cruise Control. REPAIR all C-CM (Cruise-Control Module) DTCs. TEST the system for normal operation.

No
GO to A3.

A3 CHECK THE MESSAGE CENTER FOR CORRECT OPERATION

- Check the IPC (Instrument Panel Cluster) message center for correct operation.

Does the message center operate correctly?

Yes
GO to A4.

No
REFER to Instrument Panel, Gauges and Warning Indicators to diagnose the IPC (Instrument Panel Cluster) message center.

A4 CHECK THE HUD (Head Up Display) MODULE VOLTAGE SUPPLY

- Ignition OFF.

- Disconnect: HUD (Head Up Display) Module C2395.

- Ignition ON.

- Measure the voltage between the HUD (Head Up Display) module C2395-5, circuit SBP26 (YE/RD), harness side and ground; and between the HUD (Head Up Display) module C2395-4, circuit CBP29 (WH/VT), harness side and ground.





Is the voltage greater than 10 volts?

Yes
GO to A5.

No
VERIFY the Smart Junction Box (SJB) fuse 26 (10A) or 29 (5A) is OK. If OK, REPAIR the circuit for an open. If not OK, Refer to the Wiring Diagrams to identify the possible causes of the circuit short. TEST the system for normal operation. Diagrams By Number

A5 CHECK THE HUD (Head Up Display) MODULE GROUND CIRCUIT

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Measure the resistance between the HUD (Head Up Display) module C2395-1, circuit GD114 (BK/BU), harness side and ground.





Is the resistance less than 5 ohms?

Yes
GO to A6.

No
REPAIR the circuit for an open. TEST the system for normal operation.

A6 CHECK FOR CORRECT HUD (Head Up Display) MODULE OPERATION

- Disconnect the HUD (Head Up Display) module connector.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect the HUD (Head Up Display) module connector and make sure it seats correctly.

- Operate the system and determine if the concern is still present.

Is the concern still present?

Yes
INSTALL a new HUD (Head Up Display) module. REFER to Head Up Display (HUD) Module . TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.