What Does B2320 Mean?
This code indicates the Body Control Module (BCM) has detected a fault in the feedback circuit of the potentiometer that monitors the horizontal position of the driver's side power mirror. The potentiometer provides voltage feedback to the BCM to confirm mirror position during adjustment. The BCM detected an out-of-range voltage signal, open circuit, short circuit, or erratic feedback from this position sensor.
Common Causes
45%
Faulty horizontal position feedback potentiometer inside the mirror assembly
30%
Damaged or corroded wiring/connector between BCM and driver mirror assembly
15%
Water intrusion or corrosion inside mirror assembly affecting potentiometer circuit
10%
Failed Body Control Module (BCM) with internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of driver's mirror and door panel. Check for water damage, physical damage to mirror housing, or signs of previous mirror impact. Inspect door jamb wiring harness for pinching, cuts, or damage from door opening/closing.
2
Step 2: Using a digital multimeter, backprobe the mirror connector at the door (mirror side) with ignition on. Measure reference voltage (typically 5V) and ground on potentiometer circuit. Verify supply voltage is present and stable. Check for continuity to ground on ground circuit.
3
Step 3: With mirror connector still attached, command mirror movement using power mirror switch while monitoring voltage on feedback signal wire. Normal reading should sweep smoothly between approximately 0.5V and 4.5V as mirror moves through full horizontal range. Erratic, stuck, or out-of-range readings confirm internal potentiometer failure.
4
Step 4: If voltage readings are correct at mirror connector, check continuity and resistance of all circuits between mirror connector and BCM connector (door harness). Look for opens, shorts to ground, or high resistance (should be less than 5 ohms). Flex harness while testing to reveal intermittent faults.
5
Step 5: If all wiring and connections test good, substitute a known-good mirror assembly or measure potentiometer resistance directly by removing mirror and accessing internal components (typically 1-10k ohm variable resistor). Replace mirror assembly if potentiometer is defective.
6
Step 6: After repair, clear codes, cycle ignition, and operate mirror through full range of motion in all directions. Verify code does not return and mirror operates smoothly with accurate positioning.
Estimated Repair Cost
$150 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a fault in the feedback circuit of the potentiometer that monitors the horizontal position of the driver's side power mirror. The potentiometer provides voltage feedback to the BCM to confirm mirror position during adjustment. The BCM de...
The most common cause of B2320 (Mirror Driver Horizontal Feedback Potentiometer Circuit Failure) is: Faulty horizontal position feedback potentiometer inside the mirror assembly
Typical repair costs for B2320 range from $150 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving. This code only affects power mirror positioning functionality and does not impact vehicle safety systems or driveability. Repair at convenience, though proper mirror adjustment is important for safe lane changes and backing maneuvers.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2320 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Accessories
Difficulty
Type
Generic (SAE)
Recommended Tools
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