OBD-II Code
P0263
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$400–$8,000
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
P0263 means the ECM detected cylinder 1 contribution/balance fault — on a diesel or direct-injection gasoline engine, the ECM monitors each cylinder's contribution to crankshaft acceleration on the firing stroke and compares it against the average of the other cylinders.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP0263 means the ECM detected cylinder 1 contribution/balance fault — on a diesel or direct-injection gasoline engine, the ECM monitors each cylinder'…
P0263 means the ECM detected cylinder 1 contribution/balance fault — on a diesel or direct-injection gasoline engine, the ECM monitors each cylinder's contribution to crankshaft acceleration on the firing stroke and compares it against the average of the other cylinders. The expected window varies by manufacturer but most modern systems flag a cylinder whose contribution deviates by more than 8-15% from the bank average for a sustained period, or where the injector balance rate (measured in mm^3/stroke deviation from nominal) drifts beyond roughly 2-5 mm^3/stroke from the calibration's allowable window. The cylinder is under-contributing (weak compression, fuel delivery, or injector flow) or over-contributing (stuck-open injector, dragging another cylinder's data).
Cheapest-first diagnostic ladder
- scan-tool live-data the injector balance rates (most modern diesel scan tools show per-cylinder mm^3 deviation in real time at idle) — a cylinder reading +/- 4 mm^3/stroke or more is the offender, and the sign tells you whether it's flowing more (positive deviation, stuck/dribbling injector) or less (negative deviation, clogged or worn injector).
- Swap injector wiring connectors between cylinder 1 and a known-good cylinder, clear codes, and see if the fault moves — if the balance fault follows the connector, the injector or its wiring is at fault; if it stays on cylinder 1, you're looking at mechanical compression.
- Run a relative-compression test (the scan tool can do this electronically by monitoring starter-current variation crank-by-crank on most modern diesels) — anything more than 15% below the highest-reading cylinder is mechanical.
- Perform a return-flow test with calibrated bottles on the injector returns — a cylinder 1 injector returning 200-400mL/min when its peers return 30-80mL/min is a stuck-open or worn nozzle.
- Borescope the cylinder through the glow-plug or injector port if compression is suspect. Expensive-misdiagnosis caveat: a P0263 paired with a misfire-style rough idle often gets diagnosed as 'bad injector' when the real fault is a bent pushrod, a wiped cam lobe, or a leaking head gasket — confirm compression and return flow before quoting a $400-1,200 injector replacement.
Vehicle-specific patterns2003-2007 Ford 6.0L Powerstroke throws P0263 frequently from stiction in the HEUI injectors (the cylinder 1 injector is at the front of the driver's…
- 2003-2007Ford 6.0L Powerstroke throws P0263 frequently from stiction in the HEUI injectors (the cylinder 1 injector is at the front of the driver's side and sees the most heat-cycle stress) — Hot Shot's Secret Stiction Eliminator or full injector R&R clears it.
- 2008-2010Ford 6.4L Powerstroke throws P0263 from the Bosch piezo injectors that wear or stick at the front cylinder.
- 2011-2016Ford 6.7L Powerstroke throws P0263 from CP4 contamination damage to injector nozzles — when a CP4 grenades it sends metal through all eight injectors and balance codes follow.
- 2001-2010GM Duramax LB7 is famous for cylinder balance codes (P0263/P0266/P0269/P0272 etc.) because the LB7 injectors are under the valve cover and the entire set typically fails together around 100-150k miles — GM extended warranty covered many.
- 2003-2018RAM Cummins 5.9L and 6.7L throws P0263 from Bosch injector wear or from a stuck-open nozzle on cylinder 1; relative compression testing is fast on the inline-6.
- 2009-2014Audi/VW TDI 2.0L CR throws P0263 from CP4 metal contamination and from injector nozzle wear after extended runs on low-quality fuel.
Estimated repair$400 to $8,000.
Look up another code
More free tools