What Does B2605 Mean?
This code indicates the Body Control Module (BCM) has detected a fault in the seat position sensor circuit. The seat position sensor monitors the fore/aft and height position of the power seat and communicates this information to the BCM. The fault may be an open circuit, short circuit, incorrect voltage signal, or sensor malfunction that prevents the BCM from receiving valid position data.
Common Causes
40%
Damaged or corroded wiring harness and connector at the seat position sensor
30%
Failed seat position sensor or potentiometer
20%
Broken or damaged seat track with mechanical interference preventing sensor operation
10%
Body Control Module (BCM) internal fault or software issue
Diagnostic Steps
1
Step 1: Perform a thorough visual inspection of the seat position sensor wiring harness under and behind the seat, checking for pinched wires, damaged insulation, corrosion at connectors, or loose connections. Disconnect and inspect connector terminals for bent pins or corrosion.
2
Step 2: Using a digital multimeter, check for power and ground at the seat position sensor connector with ignition ON. Verify reference voltage (typically 5V) and ground continuity (less than 0.5 ohms to chassis ground).
3
Step 3: With the sensor disconnected, measure the resistance across the sensor terminals while manually moving the seat through its range of motion. The resistance should change smoothly without sudden jumps or open circuits (typically 500-4500 ohms depending on position).
4
Step 4: Check continuity of all wires between the seat position sensor connector and the BCM connector using wiring diagrams. Look for opens, shorts to ground, or shorts to power (should have infinite resistance to ground and power when disconnected).
5
Step 5: If all wiring and sensor tests pass, verify BCM is receiving proper signals by monitoring live data for seat position values while manually moving the seat. If no data changes or erratic readings appear with good sensor, suspect BCM fault.
6
Step 6: Clear codes, cycle the seat through full range of motion multiple times, and road test to verify repair. Confirm seat position memory functions (if equipped) operate correctly.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a fault in the seat position sensor circuit. The seat position sensor monitors the fore/aft and height position of the power seat and communicates this information to the BCM. The fault may be an open circuit, short circuit, incorrect vo...
The most common cause of B2605 (Seat Position Sensor Circuit) is: Damaged or corroded wiring harness and connector at the seat position sensor
Typical repair costs for B2605 range from $150 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or driveability and it is safe to continue driving. The main impact is loss of seat position memory functions and potentially inoperative power seat adjustment, which should be repaired for comfort and convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2605 to identify the root cause.
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Quick Info
Category
Body
System
Body Comfort and Convenience Systems
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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