What Does B1658 Mean?
This code indicates that the Body Control Module (BCM) has detected a short to ground in the electrical circuit controlling the driver's seat rear up/down motor or actuator. The BCM monitors the circuit and has identified that the voltage has dropped below the expected range, indicating the circuit is grounded when it should not be. This fault prevents proper operation of the driver seat rear height adjustment function.
Common Causes
45%
Damaged or chafed wiring harness under the driver seat creating a ground short
30%
Faulty seat motor with internal short to ground
15%
Corroded or moisture-damaged connector terminals causing short circuit
10%
Failed seat control module with internal circuit fault
Diagnostic Steps
1
Step 1: Perform visual inspection of all wiring under the driver seat, checking for pinched, chafed, or damaged wires that may contact the seat frame or floor pan. Pay special attention to areas where the harness moves with seat travel.
2
Step 2: Disconnect the driver seat rear vertical motor connector and measure resistance from the motor's up circuit terminal to ground using a digital multimeter. Expected reading should be greater than 10k ohms; less than 100 ohms indicates motor internal short.
3
Step 3: With motor disconnected, check the BCM side of the circuit by measuring resistance from the seat control module's rear-up output wire to ground. Reading should be greater than 10k ohms; low resistance indicates wiring harness short to ground.
4
Step 4: Inspect all connectors in the seat circuit for corrosion, bent pins, or moisture intrusion. Clean connectors with electrical contact cleaner and verify pin integrity.
5
Step 5: If wiring and motor test normal, perform voltage drop test on the circuit while attempting to activate the rear-up function. Excessive voltage drop (>0.5V) indicates high resistance in connections or wiring.
6
Step 6: Clear codes, reconnect all components, and cycle the seat rear adjustment through full range of motion to verify repair. Re-scan for codes to confirm fault is resolved.
Estimated Repair Cost
$150 - $650
Parts + labor, varies by vehicle and location
This code indicates that the Body Control Module (BCM) has detected a short to ground in the electrical circuit controlling the driver's seat rear up/down motor or actuator. The BCM monitors the circuit and has identified that the voltage has dropped below the expected range, indicating the circuit ...
The most common cause of B1658 (Seat Driver Rear Up Circuit Short To Ground) is: Damaged or chafed wiring harness under the driver seat creating a ground short
Typical repair costs for B1658 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 drivability and it is safe to continue driving. The only impact is reduced comfort due to inability to adjust the rear height of the driver seat, which should be repaired when convenient for optimal driving position.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1658 to identify the root cause.
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Quick Info
Category
Body
System
Body Control - Power Seat System
Difficulty
Type
Manufacturer
Recommended Tools
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