Ignition Coil B Primary Control Circuit High
What does P2303 mean?
The P2303 code means the vehicle's onboard diagnostic system has detected: Ignition Coil B Primary Control Circuit High. This is a moderate severity code.
Common Symptoms
- Misfire on cylinder associated with coil B
- Check Engine Light on or flashing
- Engine running rough
- Lack of power on acceleration
- Increased emissions output
Probable Causes (Ranked by Likelihood)
- Short circuit in coil B wiring Very High
- Failed ignition coil B (internal short) High
- Coil B connector pins shorted together Moderate
- ECM coil driver output shorted Low
Step-by-Step Diagnostic Procedure
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Swap coil B to another cylinder to confirm the fault
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Check coil B connector for melted or bent pins
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Measure coil B primary and secondary resistance
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Inspect wiring for heat damage near the exhaust manifold
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Check for carbon tracking on the coil or spark plug boot
Frequently Asked Questions
Can I drive with code P2303?
Short distances only. Misfiring causes unburned fuel to enter the catalytic converter, which can cause overheating and expensive damage.
What causes P2303?
Usually a failed ignition coil or wiring damage from exhaust heat. Coils near the exhaust manifold are more susceptible to heat-related failure.
Is P2303 expensive to fix?
Usually $50 to $300. Ignition coil replacement is straightforward. Replace the spark plug at the same time for best results.