The B1971 OBD2 fault code relates to the Passenger Seatback Rearward Switch circuit. When the circuit circuit failure, the module cannot properly monitor or control this body system.
At AIscanAuto, we help drivers quickly identify OBD2 trouble codes, understand their root causes, and find the right fix.
Symptoms
- Seat not adjusting in affected direction
- Memory positions not recalling
- Possible motor noise or no response
- Heated seat may not work
Common Causes
- Faulty component — internal damage or wear affecting Passenger Seatback Rearward Switch
- Wiring issues — broken, corroded, or chafed wires in the circuit
- Connector problems — loose, oxidized, or moisture-damaged pins
- a general circuit failure is detected — can result from wiring faults, connector issues, or component failure
- Module input failure — rare, but the control module input stage may be defective
Step-by-Step Diagnosis
- Scan with OBD2 tool — Confirm B1971 is active. Check for additional DTCs.
- Visual inspection — Examine the Passenger Seatback Rearward Switch wiring and connector for corrosion or damage.
- Check voltage and ground — Use a multimeter to verify proper reference voltage.
- Test component — Compare readings to factory specs. A stuck or erratic signal confirms failure.
- Check for shorts/opens — Perform continuity tests on the wiring between the component and control module.
Repair & Solutions
- If the component is defective, replace the Passenger Seatback Rearward Switch with an OEM or quality aftermarket part.
- Repair any damaged wiring or connectors using proper methods.
- Clear the DTC with an OBD2 scanner and test drive to verify the code does not return.
- If the code persists after component replacement, inspect the control module connector.
Related Codes
- B1968 — A/C Water Pump Detection Circuit Failure
- B1969 — A/C Clutch Magnetic Control Circuit Failure
- B1970 — Passenger Seatback Forward Switch Circuit Short To Ground