Evaporative Emission System Leak Detection Pump Heater Control Circuit/Open
Diagnostic trouble code P240A indicates that the powertrain control module (PCM) has detected an open circuit or malfunction in the control circuit for the evaporative emission (EVAP) system leak detection pump heater. The PCM sets this code when the voltage or resistance in the heater control circuit falls outside of the expected operating range, preventing the heater from functioning properly.
This code primarily affects the vehicle's emissions system and will not cause drivability issues. However, it should be diagnosed and repaired to ensure the EVAP system can properly test for leaks and to pass emissions testing.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Failure to pass an emissions test
- Possible faint fuel odor near the vehicle
- No noticeable drivability issues
- EVAP system readiness monitor will not set
Likely causes
- Faulty EVAP leak detection pump heater
- Open or shorted wiring in the leak detection pump heater control circuit
- Corroded, damaged, or loose electrical connector at the leak detection pump
- Blown fuse for the EVAP system or leak detection pump circuit
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Check the relevant fuses for the EVAP system and leak detection pump.
Look for: A blown fuse indicates a short circuit that needs to be traced. If the fuse is intact, proceed to wiring and component checks.
Visually inspect the wiring harness and connector at the EVAP leak detection pump.
Look for: Look for frayed wires, broken connections, corrosion, or pushed-out pins in the connector that could cause an open circuit.
Test the leak detection pump heater control circuit for voltage and ground.
Look for: Using a multimeter, verify that the heater circuit receives battery voltage and has a good ground when commanded on by the PCM or a scan tool. Lack of voltage or ground indicates a wiring or PCM issue.
Measure the resistance of the EVAP leak detection pump heater element.
Look for: Disconnect the pump and measure the resistance across the heater terminals. Compare the reading to the manufacturer's specifications. An infinite reading (OL) indicates an open internal heater element, requiring pump replacement.
Perform a continuity test on the control wire between the PCM and the leak detection pump.
Look for: High resistance or no continuity (OL) on the control wire indicates a break in the wiring harness that must be repaired.
This page explains the generic P240A definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.