OBD Code B1248: Passenger's Seatback Autoglide Rearward Switch Circuit Short to Ground

Q: How do I fix OBD fault code B1248?

Inspect and reseat the seatback motor connector at the seat frame; corrosion or loose pins often cause ground shorts.. Check the rearward switch wire for abrasion, cuts, or damaged insulation that may contact metal frame components.. Replace the faulty rearward switch if wiring inspection reveals no damage and connector reseating fails.

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What This Actually Means

In plain language — no jargon

The passenger seatback reclining motor's backward switch wire is shorted to ground, preventing proper electrical signals from reaching the control module. Think of it like a light switch with a broken wire touching the metal frame—the circuit can't complete properly.

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Symptoms You May Notice

3 known symptoms for this code

Passenger seatback won't recline backward or moves erratically

Autoglide rearward function disabled or inoperative

Warning light or message displayed on instrument cluster

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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors voltage on the passenger seatback rearward switch circuit, expecting a normal high signal when inactive and a specific voltage drop when activated. A short to ground pulls the signal voltage to 0V abnormally, triggering a fault when the ECU detects continuous low voltage regardless of switch state.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
Switch circuit voltage	12V (inactive) to 0.5-2V (active)	Continuous 0V or <0.3V when switch should be high
Circuit resistance to ground	>10 kΩ	<2 kΩ (indicates short to ground)

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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 seatback motor connector at the seat frame; corrosion or loose pins often cause ground shorts.

2

Switch wiring and insulation

Check the rearward switch wire for abrasion, cuts, or damaged insulation that may contact metal frame components.

3

Passenger seatback switch assembly

Replace the faulty rearward switch if wiring inspection reveals no damage and connector reseating fails.

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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code B1248 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.

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How to Clear Code B1248

What happens after you fix the fault

Once the fault is repaired, B1248 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When

Fault has been diagnosed and repaired
You want to confirm the repair worked
Code appeared after a sensor was cleaned

⚠️ Do Not Clear When

Preparing for an emissions/PUC test
Root cause is still undiagnosed
Check engine light is flashing

Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.