P2579Turbocharger/Supercharger Speed Sensor A Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2579 means speed sensor A delivers a signal, but the shaft speed it reports does not fit the operating state the engine computer expects from boost, airflow and load. PACCAR bulletin E209 for 2017-2019 MX-11 and MX-13 truck engines treats P2579, alone or with P1581, as a fix-as-fail item: the sensor is replaced, because it tends to fail intermittently with a loss of power that disappears when the driver lifts off and presses the pedal again. Ram flash bulletins 18-019-20 to 18-007-24 for 2019 Ram 3500-5500 cab chassis with the 6.7 L Cummins list P2579 among codes cured by new engine software. Bentley sees it on the W12 in either engine control unit. Circuit faults are P2578 and P2580-P2582.
- What you may notice
- Sudden loss of power that returns after lifting off the accelerator
- Malfunction indicator lamp on
- Turbo speed in live data jumping or inconsistent with boost
- Likely causes
- LikelySpeed sensor A dropping out intermittently
- PossibleEngine software that misjudges the speed plausibility (update available on some models)
- PossibleIntake or boost leak that makes the shaft speed differ from the model
- RareMechanical turbocharger problem such as bearing drag or wheel damage
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €700
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.