Wiper Hi/Low Speed Relay Coil Circuit Open
The wiper relay coil circuit that controls high and low speed wiping isn't receiving proper electrical signal, like a broken switch preventing power from reaching the wiper motor. The ECU detects the coil isn't responding to commands to activate.
The ECM sends a control signal to the wiper relay coil to energize it and switch between speed modes. It monitors voltage feedback across the coil circuit during activation attempts. An open circuit prevents current flow, causing voltage to remain at battery level instead of dropping to ground.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Relay Coil Resistance | 50-150 ohms | Infinite ohms (open circuit) |
| Coil Voltage Drop | 0.5-2V during activation | 12V (no voltage drop) |
Code B1435 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, B1435 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.