What this code means
P24C0 may mean the ECM/PCM is seeing an EVAP and ELCM pressure response that does not match what it expects during leak check system operation.
What the vehicle may do
- The vehicle may turn on a warning light.
- There may be no obvious drivability symptoms.
- EVAP-related readiness or emissions testing may be affected.
Possible fault areas
- Possible ELCM system fault area.
- Possible drain or vent path concern.
- Possible canister one way valve path concern.
- Possible EVAP leak check module concern.
Diagnostic path
Open and diagnostic frame
On this Honda CR-V Hybrid, P24C0 is a canister change over valve close malfunction in the EVAP and ELCM system. In plain language, the ECM/PCM may be seeing an EVAP pressure response that does not make sense for what it expected from the leak check system. The driver may only notice a warning light, and there may not be any obvious drivability complaint. Broadly, this can point toward a possible issue in the ELCM side of the EVAP system, the drain path, the canister one way valve path, or the EVAP leak check module itself. Start with the basic system checks, then follow the test in order so you do not condemn the wrong part of the system.
Reproduce the monitor condition
First, put the vehicle into maintenance mode and start the engine. Hold engine speed at 3,000 rpm with no load, in P or N, until the radiator fan comes on, then let it idle. Next, watch the HDS EVAP PC Duty, which is the purge control duty. Hold the engine at 3,000 rpm and make sure EVAP PC Duty is at 20 % or more. Then monitor the HDS OBD STATUS for P24C0. This part is about reproducing the operating conditions before you move into the pressure checks.
Check the drain tube side
Now move to the EVAP leak check module area. Disconnect the drain tube from the EVAP leak check module. Connect a hose to the drain tube, then connect a vacuum pump/gauge, 0-30 inHg, to that hose. Apply pressure to the hose and watch the gauge. The normal result here is that pressure is not held at the drain tube.
Check the canister one way valve side
Next, remove the hose from the drain tube. Connect the hose to the canister one way valve, then connect the vacuum pump/gauge, 0-30 inHg, to that hose. Apply pressure again and watch the gauge. The normal result here is the same: pressure is not held at the canister one way valve.
Use the results
Use those two pressure checks to split the diagnosis. If the result is abnormal, the problem is in the ELCM system. If the result is normal, the problem is with the EVAP leak check module. Do not skip ahead based only on the code name; the pressure behavior is what separates those paths.
Verification and close
Keep verification separate from the component testing. After the fault path has been corrected, run the confirmation portion again: maintenance mode, warm-up to radiator fan operation, the 3,000 rpm purge-duty condition, and the HDS OBD STATUS check for P24C0. The takeaway is simple: for P24C0, prove whether the EVAP and ELCM pressure path behaves normally before blaming the module. For more diagnostic training, visit stepdiagnostics.com.
Final check
This code is best approached by reproducing the monitor condition, then using the pressure checks to separate an ELCM system problem from an EVAP leak check module problem.
For more guided automotive diagnostics, visit STEP Diagnostics.
