P24A8

Code

Generic P — Powertrain

EGR Cooler Coolant Pump Performance/Stuck Off

Brand: Generic

Type: P — Powertrain

Views: UK: 34 EN: 412 RU: 92

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Failed or seized EGR-cooler coolant pump motor
Open/short/poor connection in pump power or ground circuit
Blown fuse or faulty relay controlling the pump
Blocked or collapsed coolant hose restricting flow
Airlock or low coolant level in the cooling circuit
Faulty pump control module or PCM output driver

Symptoms

Malfunction Indicator Lamp (MIL) illuminated
Elevated EGR or exhaust gas temperatures
Reduced EGR flow or reduced engine performance under load
Coolant level drop or localized overheating symptoms
Distinct lack of pump noise/vibration when pump should be active
Possible white or grey smoke if EGR cooler is compromised

What to check

Read and record freeze frame and live data (pump commanded state, coolant temps, EGR parameters)
Check for additional DTCs related to cooling, EGR, or wiring
Visual inspection of pump, wiring, connectors, fuses and relays
Verify coolant level and inspect hoses for kinks/collapses
Listen/feel for pump operation when commanded
Check for software or technical service bulletins (TSBs)

Signal parameters

Control command: PCM output (on/off or PWM duty cycle) when EGR cooler pump should run
Supply voltage at pump connector: ~12 V when commanded on
Motor current draw: manufacturer-specific (typically under 5–10 A); unusually low or zero indicates open circuit or failed motor, excessive current indicates mechanical jam
Pump motor coil resistance: compare to spec (open = infinite ohms, shorted = low ohms)
Temperature delta across EGR cooler: should increase/decrease when pump runs (depends on circuit)
Coolant flow / pressure: measurable increase when pump commanded

Diagnostic algorithm

Retrieve freeze frame and related codes; record live parameters including pump command, coolant temp upstream/downstream of EGR cooler and EGR flow.
Perform a visual inspection: check pump mounting, hoses, clamps, signs of leakage, damaged or pinched hoses, and connector condition.
Check fuses and relays for the pump circuit; replace if blown/faulty.
With key ON (engine off) or per manufacturer procedure, command pump ON using a scan tool and verify: a) presence of battery voltage at pump power terminal, b) ground continuity, c) pump audible/vibration response.
Measure pump motor resistance with connector disconnected; compare to spec. If resistance indicates open/short, replace pump.
Measure current draw while pump is commanded. Low/zero current suggests open circuit or failed motor; very high current suggests mechanical bind or jam.
If voltage is present but pump doesn't run, bench test the pump off-vehicle to confirm mechanical/electrical condition.
Inspect/clear any debris or blockage in hoses and EGR cooler passages; perform coolant system bleed to remove air pockets and recheck operation.
If wiring or connector issues are found, repair wiring, restore proper terminals and seals, then retest.
If PCM does not command pump despite correct inputs, verify driver output with oscilloscope and consider PCM or pump control module fault; check for software updates/TSBs before replacing PCM.
After repairs, clear codes and perform warm-up and road test while monitoring pump command, coolant temps and EGR parameters to confirm fault does not return.