Wiper Hi/Low Speed Relay Coil Circuit Short To Battery
The wiper relay coil is receiving too much electrical voltage directly from the battery instead of being controlled properly by the ECU. It's like a light switch that's stuck in the 'on' position because someone's bridging the wires directly to the power source.
The ECU monitors the wiper relay coil circuit voltage to ensure it receives proper control signals. When the coil has a direct short to battery voltage, the ECU detects an abnormally high voltage that bypasses its control logic. The fault is triggered when the relay coil voltage remains at battery level instead of the expected PWM or switched control signal.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Relay Coil Voltage | 0V (off) to 12.6V (switched control) | Continuous 12.6V+ without ECU control signal |
| Relay Coil Resistance | 70-100 ohms | Short to battery detected via voltage monitoring |
Code B1436 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, B1436 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.