EVAP Emission Control Leak Detection Pump Circuit Malfunction (Volkswagen/Audi)
What does P1471 mean?
The P1471 code means the vehicle's onboard diagnostic system has detected: EVAP Emission Control Leak Detection Pump Circuit Malfunction (Volkswagen/Audi). This is a low severity code.
Common Symptoms
- Check Engine Light illuminated
- Faint fuel smell near the vehicle
- EVAP system monitor does not complete
- No noticeable drivability symptoms
- Failed emissions inspection
Probable Causes (Ranked by Likelihood)
- Failed leak detection pump (LDP) Very High
- Cracked or disconnected vacuum hose to the LDP High
- Corroded or damaged LDP electrical connector Moderate
- Wiring fault between the ECU and LDP Moderate
- Clogged LDP filter Low
Step-by-Step Diagnostic Procedure
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Locate the leak detection pump, typically near the fuel tank or charcoal canister. Check the electrical connector for corrosion.
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Test the LDP by commanding it with a scan tool. You should hear it clicking or pumping.
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Inspect all vacuum hoses to and from the LDP for cracks, kinks, or disconnections.
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Measure the voltage and ground signals at the LDP connector with a multimeter.
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Check the LDP air filter for blockage. A clogged filter prevents the pump from operating properly.
Frequently Asked Questions
What is the leak detection pump?
VW and Audi use an LDP instead of the more common fuel tank pressure sensor. The LDP physically pumps a small amount of air into the EVAP system to check for leaks by monitoring pressure decay.
Where is the LDP located?
On most VW and Audi models, the LDP is located near the rear of the vehicle, mounted near the charcoal canister or fuel tank. It is usually accessible from under the vehicle.
Can I pass emissions with P1471?
No. An active Check Engine Light will cause an automatic emissions test failure. Additionally, the EVAP system readiness monitor will not complete with a faulty LDP, which also causes a failure.