P0263 OBD-II Trouble Code: Cylinder Number 1 Contribution/Balance Fault

P0263 code definition

Cylinder Number 1 Contribution/Balance Fault

What the P0263 code means

P0263 is an [OBD-II diagnostic trouble code] which indicates that the engine control module (ECM) detected the cylinder number 1 having low contribution to the running of the engine; low power.

What causes the P0263 code?

• The number one cylinder injector is not spraying in enough fuel or no fuel at all.

• The number one injector is open or shorted electrically (other trouble codes would be present).

• The fuel pressure is low or has low volume due to a clogged fuel filter or defective pump.

• The compression in number 1 cylinder is low due to rockers, lifters, cam, rings or cylinder head gasket problems.

• The injector O-ring is leaking compression.

What are the symptoms of the P0263 code?

• The Check Engine Light will be illuminated and the code set in ECM memory and freeze frame

• The engine may run rough and low on power.

• The engine will have a misfire causing a buck or jerk and a rough idle.

• The engine may lack some power during acceleration while the misfire is active.

How does a mechanic diagnose the P0263 code?

• Scans codes and documents the freeze frame data in order to verify the problem.

• Clears the engine and ETC codes to verify whether the concern comes back

• Runs an injector electrical self test

• Checks the fuel pressure and volume to specifications

• Performs a crankcase pressure test

• Checks cylinder compression and repairs as needed

• Checks the injector O-rings and seals then replaces the injector if needed

Common mistakes when diagnosing the P0263 code?

• Failing to verify the code returns after scanning and deleting code
• Failing to check fuel pressure volume during diagnosis before replacing injector

How serious is the P0263 code?

A misfiring cylinder can cause the engine to run lean on the failed cylinder if it is an injector and cause the engine to blow black smoke if it has low compression in the cylinder.

What repairs can fix the P0263 code?

• Replacing the injector and injector seals
• Replacing the fuel filter and fuel pump
• Repairing the engine for low compression in the cylinder

Additional comments for consideration regarding the P0263 code

Code P0263 is triggered when the crankshaft sensor does not get an acceleration of the crankshaft from cylinder number 1 power stroke indicating that the cylinder is not contributing to engine power. The injector could also be shorted or open and will cause additional codes that would go with the code P0263 pointing to the injection failure.

Need help with a P0263 code?

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