Wiper Rear Park Sense Input Circuit Failure
The rear wiper system can't sense when the wiper blade has returned to its parked position, like a car that forgets where home is. This is typically caused by a broken wire, bad connector, or faulty position sensor in the rear wiper circuit.
The ECU monitors the park sense input signal from the rear wiper motor module, which provides voltage feedback when the wiper blade reaches its parked position. The module expects a clean digital signal transition within specific timing and voltage parameters when the wiper completes its cycle.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Park Sense Signal Voltage | 4.5-5.5V when parked | Below 0.5V or above 5.5V continuously |
| Signal Transition Time | 50-200ms per cycle | No transition detected or excessive delay |
Code B1822 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, B1822 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.