P0263 Cylinder 1 Contribution/Balance — Causes & Fix
Updated for 2026 diagnostics & repair guidance
P0263 at a Glance
What it means
The ECU has detected that cylinder 1 is contributing less power than expected compared to other cylinders.
Most common cause
Worn or failing fuel injector delivering insufficient fuel.
Severity
Moderate — causes rough idle and reduced performance.
Can you drive?
Yes, with caution. Performance will be reduced.
Typical repair cost
£100-£350 for injector replacement.
What Does P0263 Mean?
P0263 is a cylinder balance code. The ECU continuously monitors how much each cylinder contributes to engine speed. When cylinder 1 contributes significantly less than the others, P0263 is stored. This is almost always an injector problem — the injector is delivering too little fuel due to internal wear, carbon deposits, or a partially stuck nozzle.
Common Causes
Injector-Related Causes
Worn injector nozzle
The nozzle tip is eroded, altering the spray pattern and reducing fuel delivery. The most common cause by far.
Carbon deposits on nozzle
Carbon buildup partially blocks the nozzle openings, restricting fuel flow.
Injector solenoid weakness
A weakening solenoid does not open the nozzle fully, reducing fuel volume per injection.
Incorrect injector coding
If a replacement injector was not coded correctly, the ECU delivers the wrong fuel quantity.
Other Possible Causes
Low compression (cylinder 1)
Worn piston rings or valves reduce compression, but this is less common than injector issues.
Symptoms Drivers Notice
- Rough idle — engine feels unbalanced
- Vibration through steering wheel at idle
- Slight power loss, especially at low RPM
- Engine management light (may be intermittent)
- Marginally higher fuel consumption
Vehicles Commonly Affected
Can You Still Drive with P0263?
Yes, driving is safe but performance will be reduced. The engine is running on slightly less power from cylinder 1. Address within a week to prevent the problem worsening and affecting the DPF regeneration cycle.
How Mechanics Diagnose P0263
- 1
Read fault codes
Confirm P0263 and check for related codes (P0264-P0272 for other cylinders).
- 2
Cylinder contribution test
Use diagnostic software to run a cylinder contribution test. This shows exactly how much each cylinder is contributing.
- 3
Perform leak-off test
The leak-off test will show if the cylinder 1 injector has excessive internal wear.
- 4
Check injector coding
Verify the cylinder 1 injector code matches what is programmed in the ECU.
- 5
Compression test
If injector tests pass, perform a compression test to rule out mechanical wear.
Repair Solutions & Costs
Replace the injector
The most common and effective fix. A remanufactured injector restores full fuel delivery to cylinder 1.
Injector cleaning
Ultrasonic cleaning may help if carbon deposits are the only problem. Less effective for nozzle wear.
Recode existing injector
If the injector was recently replaced, re-coding may resolve the imbalance.
Replacing injectors? Browse our remanufactured diesel injectors, reconditioned injectors or refurbished diesel injectors — all bench-tested with a 12-month warranty.
When Injector Replacement Is Required
Replacement is required when the leak-off test shows elevated return flow, the cylinder contribution is more than 15% below average, or the injector has more than 100,000 miles of use.
Compatible Remanufactured Injectors
OEM bench-tested injectors for engines affected by P0263 — verified pricing, 12-month warranty, free UK delivery.
Bosch 0445110369
VW/Audi 2.0 TDI (EA189/EA288) Remanufactured Common Rail Injector
Fits: CDLC, CFFA, CFFB, CFFD
View injector
Bosch 0445110351
1.3L Multijet/JTD/TDCi/HDi/DDiS Remanufactured Common Rail Injector
Fits: 1.3JDTM, 1.3JTD, 1.3SDE, 169A1.000
View injector
Bosch 0445110375
Remanufactured Bosch 0445110375 diesel injector for Renault, Nissan and Vauxhall 2.0 dCi (M9R) and 2.3 dCi (M9T) applications. Direct replacement for Renault Trafic, Master, Nissan Primastar, NV400 and Vauxhall Vivaro, Movano. Cross-references 0445110634, 0986435205, 0986435234, 166005070R, 8200912052 and 93168212. Not interchangeable with Continental/Siemens M9T variants or newer Euro 6 Bosch injectors. OEM-tested and calibrated with full flow and leak-back verification on CR318 PRO test bench. Includes 12-month unlimited-mileage warranty. Supplied as an exchange unit — return your old injector within 30 days.
Fits: M9R630, M9R692, M9T670, M9T672
View injector
Siemens VDO / Continental 562002010
Renault / Nissan 2.3 dCi (M9T) Remanufactured Common Rail Injector
Fits: M9T700, M9T702, M9T704, M9T706
View injector
Siemens VDO / Continental A2C59511612
1.4L HDi/TDCi Remanufactured Common Rail Injector (PSA DV4 — Peugeot/Citroen/Ford/Mazda/Toyota)
Fits: 2WZTV, 8HT, 8HX, 8HZ
View injector
Bosch 0445116022
Bosch 0445116022 remanufactured piezo common-rail diesel injector for the Volkswagen Group 3.0 V6 TDI engine (OE 059130277BE) — Audi A4/A5/A6/A7/Q5/Q7, VW Touareg and Porsche Cayenne. Professionally tested and calibrated to OEM specification. Includes: OEM Tested, 12 Month Warranty, Free UK Delivery.
Fits: CAMA, CAMB, CAPA, CASA
View injector
Siemens VDO / Continental 562001910
Renault / Nissan / Vauxhall 2.3 dCi (M9T) Remanufactured Common Rail Injector
Fits: M9T678, M9T680, M9T686, M9T694
View injector
Bosch 0445110188
Remanufactured Bosch 0445110188 diesel injector for PSA 1.6 HDi, Ford 1.6 TDCi, Volvo 1.6 D2 and Mazda 1.6 diesel applications. Direct replacement for Peugeot 307, 308, 407, Partner, Citroen C4, C5, Berlingo, Ford Focus, C-MAX, Volvo S40, V50 and Mazda 3. Cross-references 0445110136, 0986435090, 1980H3, 1980E5, 3M5Q-9F593-CA, 30757314. OEM-tested and calibrated with full flow and leak-back verification on CR318 PRO test bench. Includes 12-month unlimited-mileage warranty. Supplied as an exchange unit — return your old injector within 30 days.
Fits: 9HY, 9HZ, G8DA, G8DB
View injectorCompatible Injector Part Numbers
2 injectors compatible with engines affected by P0263.
Cross Reference Numbers
OEM and alternative part numbers for injectors affected by P0263.
Affected Vehicle & Engine Combinations
Trusted Injector Families for These Engines
Verified remanufactured injector families fitted to engines documented to log P0263.
0445110369
Bosch · VW/Audi 2.0 TDI (EA189/EA288)
Engines: CDLC, CFFA, CFFB, CFFD, CFFE, CFGB
0445110351
Bosch · 1.3L Multijet/JTD/TDCi/HDi/DDiS
Engines: 1.3JDTM, 1.3JTD, 1.3SDE, 169A1.000, 169A5.000, 199A3.000
0445110375
Bosch · 2.0L / 2.3L dCi
Engines: M9R630, M9R692, M9T670, M9T672, M9T676, M9T690
562002010
Siemens VDO / Continental · Renault / Nissan 2.3 dCi (M9T)
Engines: M9T700, M9T702, M9T704, M9T706, M9T710, M9T716
A2C59511612
Siemens VDO / Continental · 1.4L HDi/TDCi
Engines: 2WZTV, 8HT, 8HX, 8HZ, DV4C, DV4TD
0445116022
Bosch · 3.0L V6 TDI
Engines: CAMA, CAMB, CAPA, CASA, CASB, CCWA
Need a Replacement Injector?
UK-tested remanufactured injectors with 12-month warranty. Search by engine code or vehicle registration.
Need it fast? Same-day dispatch on in-stock injectors.
Order before 2pm for next working day delivery (UK mainland). Call us on 020 3355 6581.
Engine-Specific Guides
Frequently Asked Questions
Explore Related Content
- Diesel Injector Failure Symptoms: 9 Warning Signs You S...
- Diesel Engine Misfire Causes: Injector Faults & Diagnos...
- White Smoke from Diesel Engine: Causes, Injector Faults...
- Hard Starting Diesel in Cold Weather: Causes, Diagnosis...
- Car Shaking at Idle (Diesel): Injector & Engine Vibrati...
- Diesel Injector Leak-Off Test: Step-by-Step Guide for A...
- Injector Coding After Replacement: Complete Guide by Ve...
- How to Remove and Replace Diesel Injectors: Complete Wo...
Keep Exploring
Fault Codes
Symptoms
Why It Happens
Common-rail injectors live at extreme pressures with clearances measured in microns. Fuel quality, heat cycles and mileage wear the internal control valve and nozzle: back-leak rises, spray patterns deteriorate and delivery drifts from calibration. Most 'engine' complaints on high-mileage diesels trace back to this gradual injector wear.
Professional Diagnosis
Workshops follow a fixed order: scan for codes and freeze-frame data, compare requested vs actual rail pressure on live data, read cylinder balance corrections, then run a comparative leak-off test. That sequence identifies the faulty injector without guesswork — and prevents needlessly replacing pumps, sensors or the wrong injector.
Typical Workshop Findings
The most frequent findings are: one injector returning several times the leak-off volume of its neighbours; carbon build-up from a failed copper washer; corroded injector connectors; and missing injector coding after a previous repair. Genuine high-pressure pump failures are rarer than back-leak faults that mimic them.
When to Replace Injectors
Replace when testing proves internal wear: leak-off clearly above the other injectors, balance corrections at their limits, or a failed bench test. Cleaning and additives cannot restore worn internal clearances. Bench-tested remanufactured injectors restore original calibration at a fraction of the new price — always coded to the ECU where the engine requires it.
Need help finding the right injector?
Search by part number, OE reference or vehicle registration.
Find My Injector →Know your engine code?
Browse tested injectors for your exact engine.
Search by Engine →Need a diagnosis?
Match your symptoms to the likely injector fault.
See Symptoms →Need Help With P0263?
Our diesel specialists can help diagnose the issue and find the right injector.