P24D4 code meaning
EGR Cooler Coolant Pump Feedback Circuit
Powertrain system Generic code P24xx codes Check engine light
What P24D4 means
Where an electric auxiliary pump moves coolant through the EGR cooler, the pump usually reports back to the engine controller on a separate wire, for example with a speed or status signal. P24D4 is the general fault of that feedback circuit: the signal is missing or cannot be interpreted, while the narrower cases of a line stuck below or above its band are P24AC and P24AD. The drive side may be fine; faults in the control line are P24A7 to P24AA. No manufacturer documents P24D4 publicly. CARB requires the controller to check inputs from emission-related components for circuit faults and rationality. Pierburg describes EGR coolers as part of the coolant circuit. Without valid feedback the controller cannot prove the cooler is supplied and may cut back EGR to protect it.
P24D4 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P24D4
- Malfunction indicator lamp on
- EGR reduced, possibly higher NOx and changed engine noise
- Coolant temperature warnings if the pump really stops
Common causes of P24D4
- Most likelyOpen feedback wire or loose connector at the pump
- PossibleFailed pump electronics no longer sending a status signal
- PossibleBlown fuse or failed relay leaving the pump without power
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 P24D4 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). |
| D4 | The exact fault in that area. |
What to do next
- Note P24D4 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 P24D4
What does P24D4 mean?
P24D4 means "EGR Cooler Coolant Pump Feedback Circuit". Where an electric auxiliary pump moves coolant through the EGR cooler, the pump usually reports back to the engine controller on a separate wire, for example with a speed or status signal. It is a generic code, so it means the same on every make.
Is it safe to drive with P24D4?
Drive gently and only to a workshop. With P24D4 the car can go into limp mode (reduced power) to protect itself.
Will P24D4 fail an emissions test?
Yes, it can. P24D4 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 P24D4 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P24D4 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.