Left Rear Backup Lamp Circuit Failure
The left rear backup lamp isn't working or the circuit has an electrical problem, similar to a light switch that's stuck or wired incorrectly. The ECU detected a fault in the backup lamp circuit—either an open circuit, short, or the lamp didn't respond as expected.
The ECU monitors the backup lamp circuit for proper voltage and current draw when reverse gear is selected. It expects to see a closed circuit with normal resistance when the lamp should activate, and an open circuit when it should be off. If the ECU detects voltage outside normal parameters or no response from the lamp circuit, it sets this fault code.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Circuit Voltage | 12V nominal when lamp is on; 0V when off | Voltage stuck high, stuck low, or erratic |
| Circuit Resistance | 4-8 ohms (lamp and wiring) | Open circuit (infinite) or short (near 0 ohms) |
Code B2525 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B2525 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.