How severe is fault code C1273?

Serious — Stop or limit driving

OBD Code C1273: Motor # 2 Input Circuit Short to Vbat

Q: What does OBD code C1273 mean?

Motor # 2 Input Circuit Short to Vbat. Motor #2 (typically an auxiliary motor or solenoid) has a wiring short that's connecting it directly to battery voltage when it shouldn't be. This is like a light switch stuck in the ON position, draining power and preventing normal operation.

Q: What are the symptoms of fault code C1273?

ABS warning light or stability control light illuminated, Loss of ABS or traction control functionality, Possible battery drain or electrical burning smell

Q: How do I fix OBD fault code C1273?

Locate and inspect the Motor #2 wiring for damaged insulation, pinch points, or corrosion; repair or replace the affected wire segment.. Disconnect and clean the connector pins; check for corrosion, bent pins, or moisture that could cause a short.. If wiring is intact, the motor itself may have internal short; replace the motor assembly.

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What This Actually Means

In plain language — no jargon

Motor #2 (typically an auxiliary motor or solenoid) has a wiring short that's connecting it directly to battery voltage when it shouldn't be. This is like a light switch stuck in the ON position, draining power and preventing normal operation.

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Symptoms You May Notice

3 known symptoms for this code

ABS warning light or stability control light illuminated

Loss of ABS or traction control functionality

Possible battery drain or electrical burning smell

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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the voltage input on Motor #2's control circuit. The circuit should cycle between ground and operating voltage under normal conditions. A short to Vbat (battery voltage) means the ECU detects continuous battery voltage when the motor should be off, indicating insulation failure or a direct short in the wiring harness.

Voltage & Parameter Thresholds

Parameter	Normal Range	Fault Condition
Motor #2 Input Voltage	0V (off) to 5V-12V (modulated control)	Constant Vbat (12-14V) regardless of command state
Circuit Resistance	>10 kΩ when de-energized	<100Ω (direct short path to battery)

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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex

1

Wiring harness inspection/repair

Locate and inspect the Motor #2 wiring for damaged insulation, pinch points, or corrosion; repair or replace the affected wire segment.

2

Motor #2 connector

Disconnect and clean the connector pins; check for corrosion, bent pins, or moisture that could cause a short.

3

Motor #2 solenoid/motor assembly

If wiring is intact, the motor itself may have internal short; replace the motor assembly.

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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code C1273 is classified as a serious fault. If your check engine light is flashing — not just steady — pull over safely and do not continue driving. A flashing CEL indicates an active misfire or critical failure that can cause catalytic converter damage within minutes or permanent engine harm within miles. Contact a certified mechanic immediately. Do not attempt roadside repairs on high-severity codes unless you are trained to do so.

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 C1273

What happens after you fix the fault

Once the fault is repaired, C1273 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.