B1731
Seat Driver Rear Down Switch Circuit Short To Battery
Body Chassis/Safety Seat Control 🟢 Low — Fix at next service
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What This Actually Means
In plain language — no jargon

The driver's rear seat down switch is sending a constant "battery power" signal to the ECU instead of the normal on/off pattern, like a light switch stuck in the on position. This electrical short prevents the seat control system from properly detecting when you want to move the seat.

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Symptoms You May Notice
3 known symptoms for this code
Seat down control not functioning or behaving erratically
Seat warning light or message displayed on dashboard
Inability to adjust rear seat position downward
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the voltage signal from the driver's rear seat down switch circuit. It expects to see a normal operating voltage range when the switch is activated and ground when inactive. A short to battery means the circuit is continuously reading maximum voltage, causing the ECU to detect an abnormal electrical condition.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
Switch Voltage 0V (inactive) to ~5V (active) Continuous battery voltage (~12V)
Circuit Resistance High resistance when inactive, low when active Continuous low resistance indicating short to power
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Wiring harness connector
Inspect and reseat the rear seat switch connector at the seat base to eliminate poor contact.
2
Rear seat down switch
Replace the faulty switch unit if corrosion or internal failure is confirmed.
3
Wiring and insulation
Repair any pinched, frayed, or damaged wiring in the seat control circuit between switch and ECU.