Diagnostics and check of lanterns of a backing (Discovery 3)

Inspection and verification

1. Make sure the customer's complaint is valid.

2. Visually inspect for obvious electrical problems.

Mechanical factors	Electrical Factors
Condition and installation of the reversing lamp Lamps and installation Lamp holders and installation	Fuses Battery Electrical Junction Box (BJB) - fuse link 16E BJB - fusible link 11E Central electrical box (CJB) - fuse 5P Wiring harness Loose or corroded connector (ov) Reverse lamp relay Battery Electrical Junction Box (BJB) Central electrical box (CJB) transmission control module (TCM) Electrical circuits can (Control Area Network)

3. If an obvious cause of a problem you identified or described by a customer is found, resolve it before proceeding to the next steps (if possible).

4. Use an approved diagnostic system or scan tool (tester), to retrieve all DTCs before referring to the symptom table or DTC index (DTC).

Since DTCs are stored in more than one module, a complete vehicle data readout is recommended.

Clear all DTCs after troubleshooting.

Symptom table

Symptom	Possible reasons	Actions
Flashlight not working (And) reversing	Lamp failure Fuse (And) burned out Electrical circuit malfunction No reversing light switch signal	Check the condition of the lamp and fuse (see visual inspection table). Check the electrical circuits of the reversing lights. Refer to the electrical manual. Check for DTCs that indicate a malfunction in the reverse light circuits.
dim lantern light (to her) reversing	Incorrect lamp power Electrical circuit malfunction	Check the condition and power of the lamp. Check the electrical circuits of the reversing lights. Refer to the electrical manual.

DTC index

NOTE: Universal Scan Tools cannot read the listed codes or can only read 5-digit codes. Match the 5 digits from the scan tool with the first 5 digits of the listed 7 digit code to identify the problem (the last 2 digits give additional information read by the diagnostic system approved by the manufacturer).

DTCs	Description	Possible reasons	Actions
B1C8812	Reversing lamp relay coil circuit	Reversing light relay coil circuit short circuit to battery	Check reverse light relay coil and circuits. Refer to the electrical manual.
B1C8814	Reversing lamp relay coil circuit	Reversing light relay coil circuit high resistance Reversing light relay coil circuit short circuit to ground	Refer to the guided diagnostic program for this code on the approved diagnostic system.
B1C8912	Reversing Lamp Relay Output Circuit	Reverse Lamp Relay Output Circuit Short to Battery	Refer to the guided diagnostic program for this code on the approved diagnostic system.
B1C8914	Reversing Lamp Relay Output Circuit	Reversing light relay coil output circuit high resistance Reversing light relay coil output circuit short to ground	Refer to the guided diagnostic program for this code on the approved diagnostic system.
U1A1449	CAN initialization failure	Internal electronic fault	Check the power circuits and grounds of the device. Refer to the electrical manual. Customize the module configuration (modules), using an approved diagnostic system. If a module is suspected, refer to the warranty policy and procedures manual.