Powertrain, generic (extended)

P24BC EVAP System Leak Detection Pump Pressure Sensor Circuit Intermittent

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

P24BC is meant for a pressure signal from the leak check module that drops out or jumps briefly, too short to latch the low or high limit. No manufacturer documents P24BC publicly. The closest published logic is Mitsubishi's noise check on the same sensor in the 2023 Outlander PHEV, which counts signal crossings during the engine-off test and fails above 20 events, but Mitsubishi reports that under P24B9. CARB expects EVAP sensors to be watched for circuit faults as well as erratic behaviour. Because the fault comes and goes, check the harness near the canister and fuel tank for chafing, water in the connector and loose terminals before replacing the module. Steady faults are P24BA (low) and P24BB (high).

Likely causes

Loose or spread terminal in the leak check module connector
Harness chafing near the canister or tank, intermittent short or break
Water or corrosion in the module connector
Sensor in the leak check module failing intermittently

Symptoms

  • Malfunction indicator lamp on, sometimes going out again
  • EVAP readiness monitor completes only occasionally

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–450
Time0.5–2.5 h

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

Parts involved

evap leak detection pump pressure sensor

Related codes

P24B8P24B9P24BAP24BBP2407

References: law.cornell.edu, mitsubishitechinfo.com.