P0263 Code: Cylinder 1 Contribution/Balance
Cylinder 1 is producing noticeably more or less power than the others, beyond what fuel trim can correct.
Safety first · Consult a professional
- Fuel vapor is flammable. No smoking or open flames; work outdoors and fix fuel leaks before driving.
At a glance
Severity: Moderate
- Meaning
- Cylinder 1 Contribution/Balance
- System
- Fuel & Air Metering · Powertrain
- Safe to drive?
- With caution
- Typical repair cost
- $150–$7,000
- DIY difficulty
- Hard
At idle, the engine computer times the tiny speed-up of the crankshaft that each cylinder produces as it fires. On a diesel it then trims each injector's fuel quantity so all cylinders pull evenly; that per-cylinder correction is what scan tools show as balance rates or contribution. P0263 sets when cylinder 1 needs a correction beyond the allowed limit, either because it's weak (the computer keeps adding fuel) or because it's too strong, usually a leaking injector adding fuel of its own. You see it mostly on diesel pickups such as the Power Stroke, Duramax and Cummins and on TDI-type diesels, and occasionally on gasoline direct-injection engines. On the 6.0 and 6.4 Power Stroke, cylinder 1 is the front cylinder on the passenger side, easy to reach compared with the rear ones, which makes it one of the cheaper cylinders to fix.
Can I keep driving? Usually drivable with a rough idle or a slight miss, but don't ignore it: a leaking injector can wash the cylinder wall, dilute the oil or burn a piston over time. Check the oil level for rising fuel and avoid heavy towing until it's diagnosed.
How to read P0263
- P Powertrain
- 0 Generic (SAE)
- 2 Fuel & air (injector circuit)
- 63 Specific fault
Symptoms
- Rough or lopey idle, strongest right after a cold start
- Light knock or miss that smooths out as the engine warms
- White or gray smoke at startup
- Slight loss of power under load
- Oil level rising or smelling of fuel on the dipstick
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Worn or sticking injector 1 (on the 6.0 Power Stroke, spool valve stiction with cold oil)
- Low compression in cylinder 1 from a valve, ring or head gasket problem
- Low injector drive voltage from a weak FICM (6.0 Power Stroke) or high resistance in the injector 1 wiring
- Glow plug 1 burned out, so the cylinder fires late or not at all when cold
- Injector 1 sealing washer or cup leaking combustion gas
- Replacement injector installed without programming its correction code
- Crankshaft position signal disturbed by a damaged reluctor or sensor
Diagnosis step by step
Locate cylinder 1 on your engine
On the 6.0 and 6.4 Power Stroke it's the passenger-side front cylinder; the 6.7 Power Stroke also starts at the passenger front. Duramax cylinder 1 sits at the driver-side front, Cummins cylinder 1 at the fan end and TDI cylinder 1 at the timing belt end.
Tools: Flashlight
Note when the code appears
Freeze frame and your own observation tell a lot. Rough only in the first minute after a cold start points to glow plug 1 or injector stiction; rough all the time, warm or cold, points to the injector or compression.
Tools: OBD-II scanner
Compare contribution data at warm idle
With the engine fully warm and accessories off, read the balance or contribution values for all cylinders. A cylinder 1 value far outside the others confirms the code; if every cylinder is scattered, check fuel supply and air in the fuel first.
Tools: OBD-II scanner
Check injector drive and glow plug 1
On the 6.0, FICM voltage should hold near 48 volts key on, cranking and running; readings dropping toward 45 volts while cranking mean a weak module. Measure glow plug 1: most read roughly 0.5-2 ohms, and an open reading means it's dead.
Tools: Multimeter, OBD-II scanner
Run a cylinder cut-out or contribution test
A capable scan tool can disable each injector in turn at idle. A healthy cylinder causes a clear rpm drop when cut; if cutting injector 1 barely changes anything, cylinder 1 isn't doing its share. Never crack high-pressure lines on a running common-rail engine to do this.
Tools: OBD-II scanner
Confirm compression before buying an injector
A relative compression test or a diesel compression gauge in the glow plug or injector bore settles it. Warm light-duty diesels usually read somewhere around 350-450 psi; a cylinder 1 more than about 10% below the others needs mechanical repair, not an injector.
Tools: Compression tester
Where the parts are
- 1Ignition coil
- 2Spark plug
- 3Fuel injector
- 4Camshaft sensor
- 5Crankshaft sensor
- 6Engine computer (ECM)
- 7Intake manifold
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace glow plug 1 | Yes | $150–$400 |
| Repair or replace FICM (6.0 Power Stroke) | No | $400–$1,200 |
| Replace injector 1 and program its code | No | $700–$1,600 |
| Replace all injectors | No | $3,500–$7,000 |
| Cylinder head or valve repair for low compression | No | $2,500–$6,000 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Ford
The 6.0 Power Stroke is known for contribution and balance codes caused by injector stiction, which is worst with cold or degraded oil, and by a weak FICM that can't deliver full injector voltage. Checking FICM voltage and oil condition comes before replacing injectors.
Emissions / smog test impact
Depends
Diesel testing varies by state: many heavier pickups are exempt or tested differently, but where a diesel gets an OBD check, the active check engine light fails it. Light-duty diesels such as TDI cars are OBD-tested in most emissions states.
Frequently asked questions
Does P0263 mean injector 1 is bad?
Often, but not always. The code only says cylinder 1 is out of balance; low compression, a dead glow plug or low injector drive voltage produce the same result. Test those before paying for an injector.
Why is it only rough when cold?
Cold-only roughness points to glow plug 1 or, on HEUI engines like the 6.0 Power Stroke, injector stiction with thick oil. Once the engine warms, the cylinder catches up and the balance evens out.
Is P0263 the same as P0301?
No. P0301 is a detected misfire. P0263 means the engine computer can't balance cylinder 1's power output with fuel corrections, which can happen without a full misfire. They do often appear together.
Should I replace one injector or the whole set?
If the other cylinders' contribution values are healthy, one injector with its correction code programmed is reasonable. On high-mileage engines where several cylinders are near the limit, a full set avoids paying the labor again soon.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- ISO 15031-6 – Road vehicles, diagnostic trouble code definitions (EOBD)
- Manufacturer public service information (cross-checked)
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy