P2402 — Evaporative Emission System Leak Detection Pump Control Circuit #

Note: The description for this OBD-II code may vary depending on the vehicle’s manufacturer.

• Toyota/Lexus: EVAP System Leak Detection Pump Control Circuit High
• BMW: DMTL Pump Control Circuit High
• Volkswagen/Audi: EVAP Leak Detection Pump Control Circuit – High Input
• Chrysler/Jeep: EVAP System Leak Detection Pump Control Circuit High

Summary of Code P2402 #

Code P2402 indicates a detected problem within the Evaporative Emission System (EVAP) Leak Detection Pump (LDP) Control Circuit. In simpler terms, your vehicle’s onboard computer (the PCM, or Powertrain Control Module) has noticed an electrical fault—often “high voltage”—in the circuit responsible for managing the pump that checks for vapor leaks in the EVAP system. The EVAP system is crucial for containing gasoline vapors and preventing them from escaping into the atmosphere. When this control circuit malfunctions, it may compromise the system’s ability to monitor and contain fuel vapors effectively. This code is often triggered by electrical issues, component failures, or wiring problems. While it often won’t leave you stranded, it’s a sign your emissions system needs attention.

Common Symptoms for Code P2402 #

A malfunction in the LDP control circuit may not always cause dramatic driveability issues, but the vehicle will usually alert you in some unmistakable ways. Most drivers first notice a warning light, but there can be subtle signs that the system isn’t functioning as it should.

• Check Engine Light (CEL) illuminated on the dashboard
• Failed emissions test or readiness monitors incomplete
• Fuel odor (rare, but possible if a related leak exists)
• Possible decrease in fuel efficiency
• Intermittent clicking or humming noise near the fuel tank (if the pump is malfunctioning)

Probable Causes for Code P2402 #

The most likely reasons for a P2402 code are electrical or component-related faults within the leak detection pump circuit. The control circuit consists of wiring, connectors, and the pump itself, which can all be affected by wear, corrosion, or physical damage. Diagnosis should begin with the most common causes and proceed to less frequent issues.

1. Faulty leak detection pump (LDP): The pump motor or internal circuitry has failed.
2. Damaged, shorted, or corroded wiring/connectors: Electrical connections in the pump control circuit are compromised.
3. Faulty PCM (Powertrain Control Module): Rare, but the PCM may fail to properly control or read the circuit.
4. Blown fuse or failed relay: The circuit is protected by a fuse or relay that may have failed.
5. Aftermarket modifications: Poorly installed accessories or alarms interfering with the EVAP circuit.

Step-by-Step Diagnostic Guide for P2402 #

A systematic approach is essential for isolating the fault in the leak detection pump control circuit. Even if you’re not an OEM-trained technician, methodical inspection and basic testing tools will help diagnose the issue.

• Step 1: Confirm the code with a professional scan tool and note any related codes (especially other EVAP or electrical DTCs).
• Step 2: Inspect the leak detection pump and its harness visually. Look for damaged wires, disconnected plugs, or signs of corrosion.
• Step 3: Test the leak detection pump by applying power and ground directly (following OEM instructions) to check if it operates.
• Step 4: Check for proper voltage and ground at the pump connector using a multimeter. Compare readings to the manufacturer’s specifications.
• Step 5: Inspect the related fuses and relays. Replace any that are blown or show signs of damage.
• Step 6: If no issues are found, check continuity and resistance in the wiring between the pump and PCM, repairing any faults.
• Step 7: As a last resort, consider PCM diagnosis or replacement, but only after all other sources have been ruled out.

Possible Repairs for Code P2402 #

Repairs for P2402 will directly address the root cause identified during the diagnostic process. Always verify the repair by clearing the code and completing a drive cycle to see if the code returns.

• Replace the leak detection pump (LDP) if it is faulty or inoperative.
• Repair or replace damaged wiring or connectors in the control circuit.
• Replace blown fuses or faulty relays associated with the EVAP system.
• Clean and secure all electrical connections to prevent future corrosion or resistance issues.
• Replace or reprogram the PCM (rare; only if all other repairs have failed and diagnostics confirm a module fault).

Is It Safe to Drive with Code P2402? #

Generally, you can continue driving with code P2402 for short periods, as it does not pose an immediate risk to the engine or safety systems. However, your vehicle may fail an emissions inspection, and prolonged driving with this code could allow fuel vapors to escape, contributing to air pollution. If the problem is left unresolved, it could also mask other EVAP-related faults or eventually lead to more severe issues. Timely repair is recommended to restore full emissions compliance.

Vehicles Most Commonly Affected by Code P2402 #

While P2402 can occur in many modern vehicles equipped with leak detection pumps, certain makes and models are more frequently associated with this code due to their system design or known component weaknesses.

• Toyota & Lexus: Camry, Corolla, RAV4, ES, RX
• BMW: 3 Series (E90), 5 Series (E60), X5
• Volkswagen/Audi: Jetta, Passat, Golf, A4
• Chrysler/Jeep: Grand Cherokee, Wrangler, Pacifica
• Honda/Acura (less common): Accord, CR-V, TL

Common Mistakes & Best Practices for P2402 #

Misdiagnosis is common with EVAP codes due to the complexity of the system. Rushing repairs or skipping foundational checks can lead to wasted time and money. Here’s how to avoid pitfalls and ensure a successful repair:

• Do not replace the leak detection pump without first checking wiring and fuses. Electrical faults are more common than pump failures.
• Avoid using generic scan tools only; OEM-specific data can provide valuable insight.
• Always check for technical service bulletins (TSBs) for your specific vehicle. Sometimes the issue is known and a revised part or procedure exists.
• Clear the code and drive the vehicle after repairs to ensure the issue is resolved and the code does not return.
• Document all findings and repairs for future reference or warranty purposes.

Quick FAQ for Code P2402 #

Got questions about P2402? Here are fast answers to the most common concerns:

• Q: Will P2402 cause my car to fail a smog test?
  A: Yes, if the Check Engine Light is on or the EVAP monitor is incomplete, your vehicle will likely fail an emissions inspection.
• Q: Can I clear P2402 myself with a code reader?
  A: You can erase the code, but if the underlying issue is not fixed, it will quickly return after a short drive cycle.
• Q: Is the leak detection pump expensive to replace?
  A: Parts are moderately priced, but labor costs can vary depending on vehicle design and accessibility. Always confirm the fault before replacing the pump.