P24AC code meaning
EGR Cooler Coolant Pump Feedback Circuit Low
Powertrain system Generic code P24xx codes Check engine light
What P24AC means
Electronically commutated coolant pumps often report their state back to the controller on a separate feedback wire, typically as a speed or diagnostic signal. P24AC means that this return line sits below its valid range: shorted to ground, pulled down by a damaged pump, or permanently in an error level the pump uses to signal a dry run or blockage. The control side can be healthy at the same time, which separates it from P24A9. Signal limits are not disclosed by any maker; CARB's rules on rationality and range checks of inputs serve as the reference. Because the controller can no longer confirm pump operation, it may treat the EGR cooler as unprotected and limit EGR.
P24AC at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P24AC
- Malfunction indicator lamp on
- EGR possibly reduced
Common causes of P24AC
- Most likelyFeedback wire shorted to ground
- PossiblePump signalling an internal fault, dry run or blockage
- Less likelyCorroded feedback pin in the connector
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR cooler coolant pump
What each part of P24AC 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). |
| AC | The exact fault in that area. |
What to do next
- Note P24AC 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 P24AC
What does P24AC mean?
P24AC means "EGR Cooler Coolant Pump Feedback Circuit Low". Electronically commutated coolant pumps often report their state back to the controller on a separate feedback wire, typically as a speed or diagnostic signal. It is a generic code, so it means the same on every make.
Is it safe to drive with P24AC?
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 P24AC fail an emissions test?
Yes, it can. P24AC 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 P24AC to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P24AC clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.