Fuel and injectionGeneric OBD-II codeUrgency: Garage soon
Code P0263: cylinder 1 contribution imbalance
P0263 means: cylinder 1 contribution/balance.[1][2][3][4] The ECU has detected that cylinder 1 is performing worse than the others: for the engine to run well, all cylinders must contribute similar power. According to TaT, it detects this by monitoring variations in crankshaft speed. AutoDTCs, on its P0266 page (which describes the same mechanism for cylinder 2), explains that crankshaft acceleration is measured during each cylinder's stroke and that the code is set when that cylinder's contribution falls outside the calibrated parameters.[2][3][5]
What code P0263 means
The ECU has detected that cylinder 1 is performing worse than the others: for the engine to run well, all cylinders must contribute similar power. According to TaT, it detects this by monitoring variations in crankshaft speed. AutoDTCs, on its P0266 page (which describes the same mechanism for cylinder 2), explains that crankshaft acceleration is measured during each cylinder's stroke and that the code is set when that cylinder's contribution falls outside the calibrated parameters.[2][3][5]
It is not an injector electrical circuit code: AutoDTCs distinguishes it from a full misfire or an electrical fault, and its P0263 page relates it to codes P0261 and P0262 (cylinder 1 injector circuit low and high), which are separate. TaT says it points to a fuel supply, compression or ignition problem in that cylinder.[2][4][5]
The sources put the emphasis in different places. Autodoc Club and AutoDTCs cite the injector first; CarParts.com cites unmetered air intrusion and ignition first, and then an internal mechanical fault, the injector and the wiring.[1][3][5]
It is a generic OBD-II code (it starts with P0), so it means the same on any make; what changes from one engine to another is the most likely cause. On a four-cylinder engine, P0266, P0269 and P0272 are the same warning for cylinders 2, 3 and 4.[2][6]
Original definition (SAE J2012): Cylinder 1 Contribution/Balance[1][2][3][4]
Codes from the same family
They indicate the same problem in a specific cylinder, bank or sensor. Causes, symptoms and diagnosis are those on this page.
Causes of P0263 and its family
From most to least likely, according to the sources.
- 1Faulty cylinder 1 injector: dirty, stuck, leaking or delivering an incorrect flow. This is the first cause for Autodoc Club and AutoDTCs, and CarParts.com also cites it.[1][3][5]
- 2Injector electrical problems: damaged wiring, loose or corroded connectors.[1][3][5]
- 3Low compression in that cylinder or an internal mechanical engine fault: worn piston rings, a burnt or leaking valve, a head gasket. AutoDTCs also cites valvetrain faults, such as a worn camshaft lobe, a collapsed tappet or a valve out of tolerance.[3][5]
- 4Poor fuel supply: faulty pump or insufficient pressure, clogged filter, restricted lines, contaminated fuel or air in the circuit.[1][5]
- 5Ignition fault, for example a faulty coil.[2][3]
- 6Unmetered air entering the cylinder through vacuum leaks.[3]
- 7Drifting injector correction value: this is the per-cylinder adjustment (IQA, according to AutoDTCs) that the ECU uses to correct the flow.[5]
- 8Faulty ECU: cited only by Autodoc Club, and at the end of the list.[1]
Symptoms
- Engine warning light on in the instrument cluster.[3][5]Engine warning light: faults that cause it
- Rough idle and engine vibration or shaking at idle or under light load; it improves at higher revs.[1][5]Vibrations: faults that cause it
- Loss of power and sluggish acceleration, especially under load.[1][3][5]Less power: faults that cause it
- Misfires and hesitation when accelerating.[1]Jerking: faults that cause it
- Increased fuel consumption.[1][3][5]Uses more fuel: faults that cause it
- Hard starting, especially when cold.[1]Hard to start: faults that cause it
- Exhaust smoke: black from excess fuel, or grey or white from unburnt fuel.[1][5]Black smoke: faults that cause it
- Strange noises or engine knocking.[1]Engine knock: faults that cause it
How to diagnose P0263
In order: from the most likely and cheapest to check to the most expensive.
- 1Read the code and the freeze-frame data with a scan tool and see whether other codes are stored: for other cylinders, for the same cylinder's injector circuit or for misfires.[4][5]
- 2Check the cheapest things: the connectors and wiring of the cylinder 1 injector (corrosion, damage, play) and the vacuum hoses or any unmetered air intrusion.[1][3][5]
- 3With the scan tool, run a cylinder balance test to confirm that it is cylinder 1 that is consistently performing worse.[5]
- 4Look at the live fuel data and the injector correction values: abnormal values point towards the injector.[5]
- 5Test the cylinder 1 injector: its electrical operation and its return flow or leakage. If it is clogged or dirty, Autodoc Club recommends a professional injector clean, for example by ultrasound, before replacing it.[1][5]
- 6On petrol engines, also check that cylinder's ignition, for example its coil.[2][3]
- 7Check the filter, the condition of the fuel and the supply pressure; replace the filter if it is clogged.[1][5]
- 8If the above is fine, measure the compression of cylinder 1 and check the condition of the valvetrain.[3][5]
- 9Follow the manufacturer's diagnostic procedure before replacing parts: the sources insist that the steps vary by vehicle.[3][5]
Can I keep driving with P0263?
Garage soon
The sources agree that it must be repaired soon, without being an emergency. Autodoc Club allows short trips but does not recommend it, because a faulty injector can damage the engine and the catalytic converter. AutoDTCs classes it as moderate severity and says it normally does not leave you stranded; on its P0266 page it adds that it is not an immediate safety risk, but that a weak cylinder means loss of power and vibration, and that driving for a long time can worsen mechanical damage and consumption. CarParts.com does not state a severity.[1][4][5]
Documented faults related to P0263
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Injectors: the most serious faults by engine and car
- High severityVery frequentFrequency: Very frequentOM651Delphi piezo injector failure (220/250 CDI)Yes: 220 and 250 CDI models built between 2008 and 2011 had Delphi piezo injectors that were prone to failing and seizing in the cylinder head. Mercedes-Benz replaced them under warranty in 2009 and switched the 220 CDI to solenoid injectors from 2010-2011, but the 250 CDI kept them.Repair (garage): €3,600–€5,900
- High severityCommonFrequency: CommonBMW N52 / N53N53 piezoelectric injector failureThe N53's piezoelectric direct injectors fail frequently and cause misfires, rough idle and limp mode; replacing them is expensive and they must be coded.
- High severityCommonFrequency: CommonMZR-CDOil dilution from leaking injector seals and DPF regenerationsOn the 2.0 and 2.2 MZR-CD, injector seals that age badly and incomplete particulate filter regenerations on short journeys can let unburnt diesel into the sump, diluting the oil and leaving the engine with less lubrication.
- High severityCommonFrequency: CommonOM642Wear and failure of the Bosch piezo injectorsThe OM642's Bosch piezo injectors can fail from around 150,000-200,000 km, especially with poor-quality diesel; they cannot be repaired, only replaced. Because it is a V engine, those on the rear bank are harder to reach, which pushes up labour costs.Repair: €4,500–€6,500
Ignition coils and spark plugs: the most serious faults by engine and car
- Medium severityVery frequentFrequency: Very frequent1.4 and 1.6 16vIgnition coil failureThe individual ignition coils are the most-cited fault of the K4J/K4M in the European Renault versions: they fail frequently and cause jerking, loss of power and the engine warning light coming on. It is a cheap electrical part to replace, not internal engine damage.Appears at around 30,000 km
- Medium severityCommonFrequency: CommonBMW N43/N46Injector, ignition coil and NOx sensor failures (N43)On the direct-injection BMW N43, failures of the injectors, ignition coils (mainly in 2007-2008 units, now rare after a BMW service action) and the NOx sensor of its lean-burn combustion have been documented. The indirect-injection N46 does not have that sensor and does not suffer these failures.
- Medium severityCommonFrequency: Common1.0/1.2/1.4 EcotecIgnition coil failureThe ignition coils on this engine fail fairly often in the Corsa, Astra, Meriva and Adam, causing jerking, the engine warning light and, in the clearest cases, the engine running on one cylinder fewer; the garage fixes it by replacing the affected coil.Repair (garage): €150–€480Appears at around 15,000 km
- Medium severityCommonFrequency: Common1.4 TurboIgnition coil failureThe ignition coils of the 1.4 Turbo fail fairly often on the Mokka and Meriva B, with jerking, occasional loss of power and the engine warning light on; the garage fixes it by replacing the affected coil or coils.Repair (garage): €400–€600Appears at around 47,000 km
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityOccasionalFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- High severityOccasionalFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- High severityOccasionalFrequency: OccasionalM264/M254Poorly tightened 48 V earth wiring in the mild-hybrid system (fire risk)Mercedes-Benz has issued several recalls (2022-2025) because the 12 V and 48 V earth connections of some cars with a 48 V system may be poorly tightened: resistance rises, the connection heats up and a fire cannot be ruled out. The official workshop checks them and repairs them if necessary in an hour or more.
- High severityOccasionalFrequency: Occasional1.9 TDIUnit injector tappet wear and injector wiring damageOn the unit injector system, the tappets that operate the injectors can wear if the oil is not changed on time, and the injector wiring can be damaged by contact with oil, causing misfires or loss of power.
- Critical severityOccasionalFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
- Critical severityOccasionalFrequency: OccasionalAudi A4 B9Risk of short circuit and fire due to moisture in electrical componentsAudi recalled A4 B9 units built between May 2017 and March 2020 because moisture can seep into an electrical component and cause a short circuit, with a risk of the vehicle catching fire.Repair: €0
Frequently asked questions
What does it mean when a cylinder has a "contribution or balance" fault?
It means the ECU has established, from variations in crankshaft speed, that this cylinder contributes less power than the others. It does not say by itself what is failing: according to the sources it could be the injector, compression, ignition, fuel supply or unmetered air intrusion.[2][3][5]
What is the difference between P0263, P0266, P0269 and P0272?
Only the cylinder changes: P0263 is cylinder 1, P0266 is 2, P0269 is 3 and P0272 is 4. That is why they are covered on this same page.[2][7][8][10]
Is it the same as a misfire (P0301) or an injector electrical fault (P0261)?
No. According to AutoDTCs, this code does not flag a full misfire or an electrical fault: it measures the cylinder's contribution relative to the others. The cylinder 1 injector circuit codes are different ones (P0261 and P0262).[4][5]
Can I drive with code P0263?
Only as far as the workshop. Autodoc Club allows short trips but does not recommend it, and AutoDTCs classes it as moderate severity: it is not an immediate risk, but driving for a long time with a weak cylinder can worsen damage and consumption.[1][4][5]
Does P0263 mean the cylinder 1 injector has to be replaced?
Not necessarily. The injector is the first cause for Autodoc Club and AutoDTCs, but CarParts.com puts air intrusion and ignition before it, and compression, wiring or fuel supply can also be to blame. Before replacing anything, it is worth confirming with a cylinder balance test and measuring compression.[1][3][5]
Does P0263 mean the same on all makes?
Yes. Codes that start with P0 are generic OBD-II codes and have the same definition for all manufacturers; what varies from one engine to another is the part that tends to fail.[2][6]
Will I pass the MOT with code P0263?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[12]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- 1.Código OBD2 P0263: causas, síntomas y cómo corregirloAutodoc Club · Technical documentation · consulted 4 October 2026 · in Spanish
- 2.P0263 — Cylinder 1 Contribution/Balance FaultThe Automotive Technician (TaT) · Technical documentation · consulted 4 October 2026
- 3.P0263 Code: Cylinder 1 Contribution/BalanceCarParts.com · Technical documentation · consulted 4 October 2026
- 4.P0263 – Cylinder 1 Contribution/BalanceAutoDTCs · Technical documentation · consulted 4 October 2026
- 5.P0266 – Cylinder 2 Contribution/BalanceAutoDTCs · Technical documentation · consulted 4 October 2026
- 6.On-board diagnosticsWikipedia · Other source · consulted 4 October 2026
- 7.P0266 — Cylinder 2 Contribution/Balance FaultThe Automotive Technician (TaT) · Technical documentation · consulted 4 October 2026
- 8.P0269 — Cylinder 3 Contribution/Balance FaultThe Automotive Technician (TaT) · Technical documentation · consulted 4 October 2026
- 9.P0269 – Cylinder 3 Contribution/BalanceAutoDTCs · Technical documentation · consulted 4 October 2026
- 10.P0272 — Cylinder 4 Contribution/Balance FaultThe Automotive Technician (TaT) · Technical documentation · consulted 4 October 2026
- 11.P0272 – Cylinder 4 Contribution/BalanceAutoDTCs · Technical documentation · consulted 4 October 2026
- 12.Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish