P24A1Closed Loop Particulate Filter Regeneration Control At Limit - Temperature Too High
- 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
- Here the regeneration loop has reduced its heat input as far as possible, but the temperature ahead of the filter still runs above target. GM lists P24A1 as the negative-deviation branch of the HC injector control check in steady regeneration, again a Type B fault counted over samples; the 2014 table calls it excessive hydrocarbon injector authority, and the 2018 table shows the check behind a calibration enable flag. Hino bulletin SB-22-007 names P24A1 and P24A2 on 2020 J08 conventional trucks fitted with a certain bubbler fuel filter, fixed by fitting a revised filter. Fuel leaking from a doser or injector, a sensor reading high or an uncontrolled soot burn can cause it. Unlike P24A0 the risk is thermal stress on the filter, so engines may cut the regeneration short.
- What you may notice
- Malfunction indicator lamp on
- Regeneration aborted early
- Possible high exhaust temperature warning
- Likely causes
- LikelyHydrocarbon doser or fuel injector leaking extra fuel into the exhaust
- PossibleFuel supply part causing unstable doser pressure (Hino 2020 bubbler filter)
- PossibleExhaust temperature sensor reading too high
- RareHeavy soot load burning faster than the controller can follow
- 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 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.