Passenger Mirror Horizontal Feedback Circuit Short
The B2315 code indicates that the driver seat or mirror control module (DSM/MSM) has detected an abnormally low voltage on the passenger mirror horizontal position potentiometer feedback circuit, consistent with a short to ground. This potentiometer sends an analog position signal to the module for memory and auto-repositioning functions; a short to ground interrupts this feedback, preventing the module from storing or recalling the mirror's horizontal position.
1. Commonly Affected Makes
2. Most Common Causes
- Damaged or internally shorted horizontal position potentiometer inside the passenger mirror motor assembly
- Short to ground in the signal wire between the passenger mirror and the control module
- Corroded, bent, or moisture-damaged connector pins at the mirror harness or control module
- Defective passenger mirror motor assembly (internal potentiometer/motor failure)
- Internal failure of the seat/mirror control module (DSM or MSM), though less common
3. Symptoms You Will Notice
- Passenger mirror does not move horizontally or moves erratically
- Mirror position memory function inoperative for the passenger side
- Auto-tilt or auto-repositioning feature fails on the passenger mirror
4. Step-by-Step Diagnosis
Check for technical service bulletins (TSBs) related to mirror wiring or module issues
Inspect the passenger mirror harness and connector for damage, corrosion, or bent pins
Measure the signal voltage at the mirror potentiometer and compare to specifications
Test the potentiometer resistance between signal and ground; look for a short (near zero ohms)
If wiring and potentiometer are good, test the control module by swapping or using a known-good unit
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, the vehicle is safe to drive. The fault only affects the passenger mirror's horizontal adjustment and memory function, not drivability or safety systems.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, depending on whether the mirror assembly ($100-$250) or control module ($200-$400) needs replacement, plus labor.