Powertrain, generic (extended)

P24A8 EGR Cooler Coolant Pump Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Unlike the circuit codes, P24A8 is about the pump's effect: it is commanded on, the wiring looks fine, yet the controller concludes that it does not deliver, for example because its speed feedback stays low or the expected temperature drop across the EGR cooler is missing. Air trapped after a coolant change, a blocked impeller, low coolant level or a seized motor are the usual reasons. How a maker detects the missing delivery is not published anywhere we could verify; CARB's requirement to test outputs for function and supplier material placing the cooler within the engine's coolant loop are the footing here. P24AB is the reverse, a pump that cannot be switched off. Continued operation risks boiling coolant in the cooler and cracking.

Likely causes

Air pocket in the auxiliary circuit after service or a leak
Pump motor seized or impeller blocked
Low coolant level

Symptoms

  • Malfunction indicator lamp on
  • Coolant loss or bubbling at the expansion tank
  • EGR temperature or cooler efficiency codes may follow

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–500
Time0.5–2.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egr cooler coolant pump

Related codes

P24ABP24A7P2457P24AC

References: law.cornell.edu, ms-motorservice.com.