Wiper Rear Park Sense Input Circuit Open
The rear wiper motor's position sensor has lost electrical connection to the ECU, like a phone with a broken charging cable that can't communicate its battery level. The ECU can't detect when the wiper blade returns to its parked position.
The ECU monitors the park position switch signal from the rear wiper motor to know when the blade has returned home. This circuit should show a predictable voltage pattern when the wiper completes its cycle. An open circuit means zero or missing signal, preventing proper shutdown.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Park Position Signal Voltage | 0.5V to 4.5V (varies by cycle phase) | Open circuit (no signal detected) |
| Circuit Resistance | Below 10 ohms when closed | Above 10k ohms or infinite resistance |
Code B1823 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, B1823 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.