P24A5 code meaning
EGR Cooler Bypass Control Stuck/Open (Bank 1)
Powertrain system Generic code P24xx codes Check engine light
What P24A5 means
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.
P24A5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyHard
- Typical labor1 to 6 hours
- Clears after repairAfter a drive cycle
Symptoms of P24A5
- 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
Common causes of P24A5
- Most likelyBypass flap seized by soot and carbon deposits
- PossibleActuator, linkage or vacuum supply no longer moving the flap
- Less likelyIncorrect EGR cooler fitted at the factory
- Less likelyEngine software that sets the fault too readily
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR cooler bypass valve b1
What each part of P24A5 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| A5 | The exact fault in that area. |
What to do next
- Note P24A5 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P24A5
What does P24A5 mean?
P24A5 means "EGR Cooler Bypass Control Stuck/Open (Bank 1)". P24A5 means the bank 1 cooler bypass is mechanically stuck, and makers read that in both directions. It is a generic code, so it means the same on every make.
Is it safe to drive with P24A5?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P24A5 fail an emissions test?
Yes, it can. P24A5 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P24A5 to fix?
Difficulty: hard. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will P24A5 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.