EVAP Leak Detection Pump Insufficient Vacuum (Volkswagen/Audi)
What does P1472 mean?
The P1472 code means the vehicle's onboard diagnostic system has detected: EVAP Leak Detection Pump Insufficient Vacuum (Volkswagen/Audi). This is a low severity code.
Common Symptoms
- Check Engine Light illuminated
- Faint gasoline odor near the vehicle
- No drivability symptoms
- EVAP readiness monitor will not complete
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Loose or cracked gas cap Very High
- Leak in the EVAP system hoses or canister High
- Weak or failing leak detection pump High
- Leaking fuel tank vent valve Moderate
- Cracked fuel tank or filler neck Low
Step-by-Step Diagnostic Procedure
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Check the gas cap for cracks or a damaged seal. Tighten properly, clear the code, and monitor.
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Use a smoke machine to pressurize the EVAP system and inspect for leaks at all connections and hoses.
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Test the leak detection pump function with a scan tool to verify it builds adequate vacuum.
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Inspect the charcoal canister and all EVAP lines from the tank to the engine for damage.
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Check the fuel tank vent valve for proper sealing by applying vacuum with a hand pump.
Frequently Asked Questions
Can a gas cap cause P1472?
Yes. A loose, cracked, or worn gas cap is the most common cause of insufficient vacuum in the EVAP system. Always check the cap first before moving to more expensive diagnostics.
What is the difference between P1471 and P1472?
P1471 indicates an electrical circuit problem with the leak detection pump, while P1472 means the pump ran but could not build enough vacuum, suggesting a physical leak in the EVAP system.
How does a smoke machine help diagnose EVAP leaks?
A smoke machine pumps visible smoke into the sealed EVAP system under low pressure. Any leak will produce a visible stream of smoke, making it easy to pinpoint the exact location of the problem.