Diagnostics and testing of reversing lights (Discovery 3)

Inspection and verification

1. Ensure that the customer's complaint is justified.

2. Visually inspect for obvious electrical problems.

Mechanical factors	Electrical factors
Condition and installation of the reversing light Lamps and installation Lamp holders and installation	Fuses Battery Power Distribution box (BJB) - fuse link 16E BJB-fuse link 11E Central Power Distribution Box (CJB) - fuse 5P They are eating electrical wiring Loosening or corrosion of connector(s) Reverse Light Relay Battery Junction Box (BJB) Central Junction Box (CJB) Transmission Control Module (TCM) Electric circuits cAn (Control Area Network)

3. If an obvious cause for the problem you identified or the customer described is found, resolve it before moving on to further action. (if possible).

4. Use the approved diagnostic system or scan tool to retrieve all diagnostic trouble codes (DTCs) before referring to the symptom chart or DTC index.

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

Clear all DTCs after troubleshooting.

Table of signs of malfunction

Sign of malfunction	Possible reasons	Actions
The reversing light(s) do not work	Lamp failure The fuse(s) have blown Electrical circuit failure No signal from the reverse light switch	Check the condition of the lamp and fuse (see visual inspection table). Check the electrical circuits of the reversing lights. Refer to the electrical equipment manual. Check for DTC codes that indicate a malfunction in the electrical circuits of the reverse lights.
Dim light from reversing light(s)	Incorrect lamp power Electrical circuit failure	Check the condition and power of the lamp. Check the electrical circuits of the reversing lights. Refer to the electrical equipment manual.

DTC Index

NOTE: Generic scan tools cannot read the codes listed 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 fault. (the last 2 digits provide additional information readable by a manufacturer approved diagnostic system).

DTC codes	Description	Possible reasons	Actions
B1C8812	Reverse Light Relay Coil Electrical Circuit	Reverse Light Relay Coil Circuit: Short to Battery +	Check the reverse light relay coil and electrical circuits. Refer to the electrical manual.
B1C8814	Reverse Light Relay Coil Electrical Circuit	Reverse Light Relay Coil Circuit High Resistance Reverse Light Relay Coil Circuit Short to Ground	Refer to the guided diagnostic program for this code on the approved diagnostic system.
B1C8912	Reverse Light Relay Output Circuit	Reverse Light Relay Output Circuit: Short to Battery +	Refer to the guided diagnostic program for this code on the approved diagnostic system.
B1C8914	Reverse Light Relay Output Circuit	Reverse Light Relay Coil Output Circuit High Resistance Reverse 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 malfunction	Check the electrical power and ground circuits of the unit. Refer to the electrical manual. Configure the module(s) using the approved diagnostic system. If a module is suspect, refer to the warranty policy and procedures manual.