AutoFixDB - Free OBD-II diagnostic trouble code lookup. Find causes, symptoms, diagnostic steps and repair solutions.

Overview

P03C6 is an OBD‑II generic diagnostic trouble code indicating a combustion misfire detected on cylinder 6, typically due to ignition, fuel delivery, or mechanical issues.

Common Symptoms

Rough idle and engine vibration
Loss of power or hesitation
Check Engine Light illuminated (may flash under heavy misfire)
Reduced fuel economy

Most Common Causes

Faulty ignition coil on cylinder 6 high

Coil failure is one of the most frequently d causes for a cylinder‑specific misfire.

Worn or fouled spark plug on cylinder 6 high

Spark plug issues prevent proper ignition of the air/fuel mixture.

Clogged or malfunctioning fuel injector on cylinder 6 medium

Fuel delivery problems can lead to lean or no combustion in that cylinder.

Low cylinder compression due to mechanical wear medium

Valve, piston ring, or head gasket issues can reduce combustion performance.

Wiring or ECM/PCM driver issues low

Uncommon but possible; misinterpretation or signal faults can mimic misfire.

Diagnostic Steps

Check for additional stored codes and retrieve freeze‑frame data with a scan tool

Expected: P03C6 code present; no conflicting sensor faults

Interpretation: Verifies that the misfire is isolated to cylinder 6 and checks for related issues
Inspect and swap ignition coil for cylinder 6 with another cylinder

Expected: If misfire code follows to new cylinder, coil is faulty

Interpretation: Confirms ignition coil as root cause
Inspect spark plug on cylinder 6 for wear, fouling or damage

Expected: Abnormal plug condition

Interpretation: Indicates need for spark plug replacement
Test fuel injector operation on cylinder 6 (click test or flow test)

Expected: Injector not firing or flowing properly

Interpretation: Confirms fuel delivery issue
Perform compression test on cylinder 6 and compare to other cylinders

Expected: Significantly lower compression

Interpretation: Indicates mechanical engine issue

Repair Solutions

Replace ignition coil for cylinder 6 medium

Estimated Cost: $70 - $200

Cost varies by vehicle model and labor rates

Replace spark plug on cylinder 6 easy

Estimated Cost: $20 - $60

Often done with coil replacement

Service or replace fuel injector on cylinder 6 medium

Estimated Cost: $100 - $300

Cleaning may be effective if not severely clogged

Repair mechanical engine issues (valve/piston/rings) hard

Estimated Cost: $500 - $1500

Dependent on extent of mechanical damage

Common Misdiagnoses

Avoid these common diagnostic mistakes:

Interpreting P03C6 as cylinder 5 issue (some generic sites mislabel)
Blaming oxygen sensors or unrelated emissions sensors

Frequently Asked Questions

What is the definition of the P03C6 engine code?

Cylinder 6 Misfire Detected is the standard definition for P03C6. This diagnostic code is triggered when the ECU detects a problem in the Ignition.

Reflecting on severity: How bad is P03C6?

You should treat P03C6 as a medium issue. Engine may run rough, lose power, and have increased emissions; prolonged driving can damage catalytic converter.

How do I know if I have code P03C6?

Drivers often report: Rough idle and engine vibration, Loss of power or hesitation, Check Engine Light illuminated (may flash under heavy misfire) when this code is present.

Why is my car throwing a P03C6 code?

It can be caused by several factors, most notably: Faulty ignition coil on cylinder 6, Worn or fouled spark plug on cylinder 6, Clogged or malfunctioning fuel injector on cylinder 6.

Estimated repair costs for different causes of P03C6

Expect to pay around $60 if the issue is a Replace spark plug on cylinder 6, but up to $1500 if the Repair mechanical engine issues (valve/piston/rings) needs replacement.

What cars are affected by the P03C6 code?

The P03C6 code is a generic powertrain code, meaning it applies to almost all makes and models, such as Honda, Toyota, VW, Ford, and Chevy.

P03C6: Cylinder 6 Misfire Detected