What causes P1203 on a Honda?

Clogged or sticking cylinder 3 fuel injector Failing cylinder 3 coil-on-plug or worn spark plug Low fuel pressure affecting cylinder 3 delivery Vacuum leak near the cylinder 3 intake runner Low compression on cylinder 3 from tight exhaust valves

How do I fix P1203 on a Honda?

Confirm the cylinder 3 misfire counter with a scan tool before touching parts Swap the cylinder 3 coil and plug to another cylinder and see if the misfire follows Test the cylinder 3 injector flow and resistance Check fuel pressure against spec under load Compression and valve-clearance check cylinder 3 if spark and fuel check out

P1203 Fuel System Failure Caused No

Q: What does P1203 mean on a Honda?

P1203. Fuel System Failure Caused No. 3 Cylinder Misfire. Applies to Civic, Accord, CR-V.

Category: Powertrain - Ignition
Severity: Check Engine Light
Applies to: Civic, Accord, CR-V

This fault is part of the Honda misfire codes guide. It covers the system and the order to check it.

What does P1203 mean on a Honda?

P1203. Fuel System Failure Caused No. 3 Cylinder Misfire. This Honda-enhanced code applies to Civic, Accord, CR-V.

Common causes of P1203

Clogged or sticking cylinder 3 fuel injector
Failing cylinder 3 coil-on-plug or worn spark plug
Low fuel pressure affecting cylinder 3 delivery
Vacuum leak near the cylinder 3 intake runner
Low compression on cylinder 3 from tight exhaust valves

How to fix P1203

Confirm the cylinder 3 misfire counter with a scan tool before touching parts
Swap the cylinder 3 coil and plug to another cylinder and see if the misfire follows
Test the cylinder 3 injector flow and resistance
Check fuel pressure against spec under load
Compression and valve-clearance check cylinder 3 if spark and fuel check out

Sources and review

Last updated 2026-09-07.