P24BC: EVAP System Leak Detection Pump Pressure Sensor Circuit Intermittent

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).

Low severity. Can I keep driving?Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

Symptoms

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

Most 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

What to check, in order

Start with the simplest. You can tick off each step.

Start with the fuel cap: tighten it fully and check its seal
Gently move the wiring with the engine running and watch whether the reading changes.
Inspect the hoses and connections around the tank and the charcoal canister
Use the scanner to test the purge and vent solenoid valves
Run a smoke test to find small leaks

Good to know

Repair difficulty: medium
It affects emissions.

What each character of P24BC means

P: Powertrain: engine and transmission
2: Generic code: same on every make
4: Emissions
BC: Specific fault in that system

Frequently asked questions

Can I keep driving with code P24BC?

Yes, you can normally keep driving. If there is a strong smell of gasoline, find the leak before continuing and do not smoke nearby.

What causes code P24BC?

The most common causes are: 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.

Related codes

Sources

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.