EVAP Leak Detection Pump Control Circuit High
The P2402 code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the control circuit of the Evaporative Emission System Leak Detection Pump (LDP). This pump is part of the EVAP system, which prevents fuel vapors from escaping into the atmosphere. A high voltage signal suggests a short to power, a faulty pump, or a wiring issue. This can prevent the system from properly detecting leaks, potentially causing increased emissions and a failed emissions test.
1. Most Common Causes
- Short circuit to battery voltage in the LDP pump control circuit wiring
- Open circuit in the ground or return wire of the LDP pump
- Internal failure of the leak detection pump (shorted coil, damaged electronic component)
- Corroded, loose, or damaged connector or terminal in the LDP pump harness
- Intermittent ECM/PCM failure (less common, but possible)
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Failed emissions test
- Possible fuel odor
- No noticeable drivability issues in most cases
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes (e.g., P2401, P2403, P2404).
Step 2: Visually inspect the LDP and its wiring/connectors for damage, corrosion, or loose connections.
Step 3: Test the LDP control circuit voltage with a multimeter. With key on, engine off, the signal wire should read battery voltage. If voltage is high or erratic, suspect a short to power.
Step 4: Check the LDP resistance. Compare to manufacturer specs (typically 10-30 ohms). Replace if out of range.
Step 5: If wiring and pump are okay, test the PCM output. If no signal, the PCM may be faulty.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
Yes, it is generally safe to drive, but the EVAP system will not function properly, which may cause a failed emissions test and increased fuel vapor release. It's best to repair it soon.
How much does it cost to fix?▼
The cost typically ranges from $150 to $400, including parts and labor. The leak detection pump itself costs $50-$150, and labor adds $100-$250 depending on the vehicle.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.