The P2402 code is a generic OBD-II diagnostic trouble code indicating “EVAP Leak Detection Pump Control Circuit High.” It means the powertrain control module detected an abnormally high voltage in the leak detection pump control circuit.
This code does not automatically prove the pump has failed. Diagnosis requires verifying the OBD2 error circuit wiring, connectors, and pump resistance before replacing any components.
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Key Takeaways
- The P2402 code indicates the control module detected a high voltage condition or open circuit in the EVAP leak detection pump control circuit.
- Possible causes include damaged wiring, corroded connectors, a blown fuse, or an internally failed leak detection pump.
- Diagnosis involves inspecting the pump circuit for shorts to voltage or opens and measuring the pump’s internal resistance.
- Repairs may involve repairing the wiring harness, cleaning connectors, or replacing the confirmed failed leak detection pump.
P2402 Code Description and Implications
The P2402 code indicates that the powertrain control module detected a high voltage condition on the EVAP leak detection pump control circuit. This generic code applies to vehicles equipped with a leak detection pump, such as certain Chrysler, Jeep, Dodge, and Volkswagen applications.
The leak detection pump pressurizes the EVAP system to check for vapor leaks. The control module monitors the electrical circuit that powers and controls this pump.
When the module commands the pump and detects voltage remaining high when it should be low, or detects an open circuit, it stores this code. This is an electrical fault, not a physical vapor leak.
Common Causes of the P2402 Code
Damage to the wiring harness or corroded connectors at the leak detection pump is a primary cause. An open circuit or a short to voltage in the control wires will prevent the pump from operating correctly.
An internally failed leak detection pump solenoid or motor can create an open circuit condition, causing the control module to detect high voltage on the control line.
A blown fuse or poor power supply to the leak detection pump assembly can also result in a circuit high reading.
In rare instances, an internal fault within the powertrain control module itself may prevent it from properly grounding or controlling the pump circuit.
Symptoms Associated With P2402
An illuminated Check Engine Light is expected once the monitor detects the circuit fault. MIL behavior varies by application, but the light commands when the electrical fault is verified.
Because this is an electrical circuit code for an emissions testing component, you will likely not experience any drivability symptoms, engine performance issues, or changes in fuel economy.
The vehicle will fail an emissions inspection because the EVAP system monitor cannot run or complete its leak test while this electrical fault is present.
Diagnosing the P2402 Trouble Code
Diagnosis must begin by confirming the exact factory definition and checking for related EVAP or circuit codes. Record freeze-frame data to see the conditions when the code set.
Perform a thorough visual inspection of the wiring harness and connectors at the leak detection pump. Look for chafed wires, broken insulation, corrosion, or loose pins.
Use a multimeter to test the control circuit for continuity, shorts to voltage, and open circuits according to the manufacturer wiring diagram. Verify that the pump is receiving proper power and ground.
Measure the internal resistance of the leak detection pump solenoid or motor. Compare the reading to the manufacturer specification to determine if the pump is internally open.
Repairing the P2402 Issue
Repairs must follow confirmed diagnosis. If the wiring harness is found to be broken, shorted, or corroded, repair the circuit and secure the harness to prevent future damage.
If electrical testing confirms the leak detection pump is internally open or fails the manufacturer resistance test, replace the pump using a component meeting the exact vehicle specification.
If a blown fuse is found, replace the fuse and investigate the circuit for the underlying short or overload condition that caused it to blow.
Cost Considerations for P2402 Repairs
Cost depends on diagnostic time, component accessibility, required parts, programming requirements, and labor.
Repairing damaged wiring or replacing an externally mounted leak detection pump involves moderate parts and labor expenses.
If the pump is integrated into a larger EVAP assembly or requires extensive harness repair, the overall repair cost will increase.
Prevention Strategies for Future Occurrences
Inspecting exposed EVAP wiring harnesses and pump connectors during routine under-vehicle checks can help identify developing insulation damage or moisture intrusion before it causes an open circuit.
Keeping connector seals intact and ensuring wiring is properly secured away from hot exhaust components may reduce the risk of circuit faults.
Some electrical failures occur due to normal component aging and cannot be reliably prevented through standard maintenance.
Troubleshooting Tips and Best Practices
Do not attempt to fix a P2402 code by simply tightening the gas cap or looking for vapor leaks. This is an electrical circuit code, not a physical leak code like P0442 or P0455.
Always verify the power and ground circuits at the pump connector before condemning the pump itself. A missing ground will mimic an open circuit or high voltage condition.
Check for technical service bulletins for your exact vehicle application, as some manufacturers release updated wiring harness pigtails or revised pump designs to address chronic connector corrosion.
More OBD-II Codes
| P2099 | P2098 | P2097 | P2096 |
| P2088 | P2080 | P2404 | P2407 |
| P2419 | P242F | P2431 | P2433 |
| P0440 | P0441 | P0442 | P0455 |
| P0446 | P0449 | P0451 | P0452 |
| P0171 | P0300 | P0420 | P0174 |
Frequently Asked Questions
Is the P2402 code generic or manufacturer-specific?
The P2402 code is a generic SAE OBD-II diagnostic trouble code. However, the exact design of the leak detection pump and diagnostic steps vary by manufacturer and vehicle application.
Will a loose gas cap cause a P2402 code?
No. A loose gas cap causes physical vapor leak codes like P0455 or P0456. The P2402 code specifically indicates an electrical fault in the leak detection pump control circuit.
Can I drive my vehicle with a P2402 code?
You can typically drive the vehicle, as this code affects the emissions testing system and usually causes no drivability issues. However, the vehicle will fail an emissions inspection until the fault is repaired.
Does a P2402 code mean I need a new EVAP pump?
Not necessarily. While an internally failed pump is a possible cause, the code is frequently caused by damaged wiring, corroded connectors, or a blown fuse. Proper circuit testing is required first.
Can I clear the P2402 code without fixing the problem?
Clearing the code only resets the warning light. If the underlying wiring fault or failed pump remains, the monitor will detect the high voltage condition immediately and turn the light back on.
What Should You Do About the P2402 Code?
Confirm the exact factory definition and check for related circuit codes for your specific vehicle application. Follow the applicable manufacturer diagnostic procedure to verify whether the fault lies in the wiring, connectors, or the leak detection pump itself.
Once testing confirms the root cause, repair or replace the confirmed failed component, then retest the EVAP system monitor to ensure it completes successfully.
