What does it mean?
B2318 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Wiper Hi/Low Control Circuit High .
Symptoms
- The passenger mirror drives to one end of its side to side travel and will not come back.
- Memory recall positions the mirror incorrectly or ignores it completely.
- The mirror may move on its own when the doors are unlocked or another door function is used.
- Reverse tilt and memory storing no longer work for that mirror.
- The position value in live data stays at full scale whatever the mirror does.
Likely causes
- Feedback wire chafed inside the door against a permanently live circuit such as the window motor feed or a courtesy lamp wire.
- Water in the mirror housing or connector bridging the signal contact to a powered contact.
- Corroded, bent or pushed back terminal in the mirror or door module connector.
- Internal short in the potentiometer between the wiper track and the motor supply.
- Loom pinched or trapped when the door trim, speaker or window regulator was refitted.
- Aftermarket wiring spliced into the door harness near the mirror circuits.
- Door module input stage failure.
How to fix it
- Read the codes and check the vertical position value; a value pinned at maximum indicates the line is being held at supply voltage.
- Unplug the mirror and measure the feedback wire from the harness side with the key on; battery voltage present means the short is in the wiring.
- If the voltage disappears with the mirror disconnected, the short is inside the actuator or its potentiometer.
- Inspect the door harness along the inner panel, the regulator rail and the boot for chafing, crushing and added wiring.
- Check the mirror housing and connector for water, corrosion and failed seals, and dry everything before retesting.
- Repair the damaged section with sealed crimped joints and reroute the loom clear of moving parts.
- Replace the mirror actuator once it is proven at fault, then reprogram the mirror memory positions.