P24A5EGR Cooler Bypass Control Stuck/Open (Bank 1)
- 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
- P24A5 means the bank 1 cooler bypass is mechanically stuck, and makers read that in both directions. GM's 2017 Duramax DC-motor flap is judged stuck in bypass if the position is still above 15 % after P245B; the 2018 vacuum version is moved between both modes and fails when the gas temperature after the cooler barely reacts, both Type B. Ford's 2013 and 2015 diesel summaries use it as an overcooling test on the 6.7 L and 3.2 L: with the flap commanded to cooling, gas after the cooler stays below a coolant-based limit for 12 seconds, a sign the flap sits in cooling. Ford traced early cases on 2016–17 Transit 3.2 L vans (TSB 17-0009) to a wrong EGR cooler; Ram reflashed 2014 6.7 L Cummins trucks to cut needless lamps (18-053-14). Bank 2 is P24A6.
- What you may notice
- Check engine light on
- Slow warm-up or more soot when the flap is stuck in cooling
- Higher NOx and EGR gas temperatures when stuck in bypass
- Likely causes
- LikelyBypass flap seized by soot and carbon deposits
- PossibleActuator, linkage or vacuum supply no longer moving the flap
- RareIncorrect EGR cooler fitted at the factory
- RareEngine software that sets the fault too readily
- 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 – €1,800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.