Powertrain, generic (extended)

P24A9 EGR Cooler Coolant Pump Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modeNo

P24A9 reports that the voltage on the control line of the electric EGR cooler coolant pump is lower than the driver stage expects in its current switching state, which usually points to a harness or pump-internal short to ground, or to a chafed wire touching the engine block. Whether low means switched on permanently or not at all depends on how the manufacturer drives the pump (low-side or high-side switching, or a PWM signal). Published limits are not available from any maker, so CARB's rules for monitoring actuator circuits and supplier notes on EGR coolers stand in. Inspect the harness near hot exhaust parts for melted insulation. P24AA is the short-to-supply counterpart, P24A7 the open line.

Likely causes

Control wire chafed through and shorted to ground
Insulation melted near exhaust or EGR parts
Internal short in the pump electronics

Symptoms

  • Malfunction indicator lamp on
  • Pump may run continuously or not at all

Repair estimate

DifficultyMediumDIY possible
Parts and labour€30–450
Time0.5–2 h

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

Parts involved

egr cooler coolant pump

Related codes

P24AAP24A7P24A8

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