P026CFuel Injection Quantity A Lower Than Expected
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- From 2010, CARB requires diesel engines to detect when the commanded injection quantity is not delivered. The module estimates the fuel actually burned from airflow and the measured lambda (from the NOx or oxygen sensor) and corrects the quantity; if that correction passes a limit, the code sets. P026C means the engine gets less fuel than commanded. GM's 6.6 litre LML diesel checks it at idle with the vehicle stationary and the engine warm, setting it at a correction of −20 to −35 mm³ per stroke for 12 s; later GM diesels use the learned correction value (10 of 20 samples); both need two trips. FCA lists it with an injector cleaning procedure for deposits. Ford diesels do not use it. Typical causes are coked injectors, wrong airflow or lambda measurement and weak fuel supply.
- What you may notice
- Check engine light on
- Lack of power
- Rough running or idle
- Likely causes
- LikelyInjectors coked or clogged (too little flow)
- PossibleAirflow or boost measurement wrong, NOx sensor lambda inaccurate
- PossibleWeak low- or high-pressure supply (filter, pump, rail pressure)
- RareFuel quality or contamination
- RareSoftware
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €4,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.