What Does B2345 Mean?
This code indicates the Body Control Module (BCM) or seat control module has detected an open circuit in the negative reference voltage line (ground circuit) for one or more seat switch inputs. The control module continuously monitors the reference voltage circuits to ensure proper switch operation, and when the negative common ground circuit is interrupted or missing, it cannot properly read switch positions. This affects the seat position adjustment system's ability to function correctly.
Common Causes
45%
Broken or corroded ground wire in seat wiring harness, often due to seat movement fatigue or water intrusion
30%
Disconnected or loose connector at seat switch assembly or control module
15%
Failed seat switch assembly with internal ground circuit failure
10%
Damaged wiring due to seat rail binding or mechanical interference causing wire chafing
Diagnostic Steps
1
Step 1: Perform visual inspection of seat switch and all connectors for obvious damage, corrosion, water intrusion, or disconnected terminals. Check seat wiring harness for chafing or pinched wires along seat track movement path.
2
Step 2: Using a digital multimeter, verify continuity between the seat switch ground terminal and a known good chassis ground. Reading should be less than 1 ohm. If no continuity exists, trace the ground circuit from switch to ground point.
3
Step 3: Disconnect seat switch connector and measure resistance from the negative reference circuit pin at the BCM/seat control module connector to ground. Should read less than 5 ohms. High resistance or infinite resistance confirms open circuit in harness.
4
Step 4: Inspect ground connection point (typically under seat or at body ground stud) for looseness, corrosion, or paint contamination. Clean ground point and verify metal-to-metal contact with less than 0.5 ohm resistance.
5
Step 5: If all wiring and grounds test good, backprobe the seat switch connector with power and ground applied, then operate switches while monitoring voltage. Lack of proper ground reference confirms failed switch assembly.
6
Step 6: After repair, clear codes, cycle seat through full range of motion multiple times, and verify code does not return and all seat functions operate normally.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) or seat control module has detected an open circuit in the negative reference voltage line (ground circuit) for one or more seat switch inputs. The control module continuously monitors the reference voltage circuits to ensure proper switch operation,...
The most common cause of B2345 (Seat Switch Reference Voltage Negative Common Open Circuit) is: Broken or corroded ground wire in seat wiring harness, often due to seat movement fatigue or water intrusion
Typical repair costs for B2345 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive as this affects comfort features only. Power seat adjustments may not function properly, but the seat will remain locked in its current position. Repair at convenience unless seat is stuck in an unsafe driving position.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B2345 to identify the root cause.
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Quick Info
Category
Body
System
Body Control / Power Seat System
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
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