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1999 VW Passat 2.8L OBD-II Codes P0455, P1136, P1138, P0441: EVAP Leak and Lean Fuel Trim Fixes

Model: 1999 Passat 2.8L Fault Code: P0441 Posted: 2010-02-23 19:14

First post — I'm sharing detailed info on my 1999 VW Passat 2.8L (non-turbo) with persistent OBD-II codes: - Mileage: 127,320 miles - Detected Codes: - P0455: Evaporative Emission Control System Gross Leak Detected - P1136: Long-Term Fuel Trim Add — Fuel B1 System Too Lean (VW) - P1138: Long-Term Fuel Trim Add — Fuel B2 System Too Lean (VW) - P0441: Evaporative Emission Control System Incorrect Purge Flow I recently replaced the fuel filler cap with a new one. The original cap’s O-ring showed wetness around half its circumference, indicating possible seal failure. After installation and clearing the codes, I plan to drive the vehicle for the next few days and re-check for any return of error codes. If this issue is familiar to others, please advise if additional diagnostics or parts are needed — I’m open to suggestions. Thanks, Ron

Related fault codes
P0441P0455P1136P1138
Comments (5)
Anonymous 2010-02-24 08:25

The fuel cap may resolve EVAP-related codes — did you replace it with a dealer-original or aftermarket model? For the lean fuel trim issues (P1136/P1138), check the Mass Airflow Sensor (MAF), inspect for vacuum leaks, verify fuel pressure and flow. These are common root causes in 1999 Passat 2.8L models. Good luck — please update with your findings.

Anonymous 2010-02-24 19:41

Thanks for the advice! I used an aftermarket fuel cap to replace the original. This weekend, I’ll inspect the vacuum lines, MAF sensor, and fuel filter. Unfortunately, I don’t have a fuel pressure gauge on hand — so I’ll rely on a mechanic’s tools for testing. Will post results after the inspection. Appreciate your help — Cheers, Ron

Anonymous 2010-04-14 12:03

Apologies for the delayed response — repairs took longer than expected. Two issues were identified: 1. The P0455, P1136, and P1138 codes stemmed from two pinched vacuum hoses: one connected to the fuel pressure regulator and another to an emission control solenoid. A local mechanic replaced all original vacuum hoses. The check engine light has not returned, but I’ve asked my daughter to drive it for a few more days to build a stable code history before smog testing. 2. An overlooked issue: my rear tires were 1 inch taller than the front (P195-65R15 — correct size). This caused traction system malfunctions and unstable handling. I returned to the tire store, which corrected the imbalance with proper adjustments — now the vehicle handles smoothly. I’ll update again once the Passat passes California smog inspection. Thanks for your patience — Cheers, Ron

Anonymous 2010-05-12 10:54

After further diagnostics with a trusted local mechanic, I discovered a faulty evaporative control valve that was stuck open — this was the primary cause of all OBD-II codes (P0455, P1136, P1138, P0441). The part cost $134 and labor totaled $236. Total repair: ~$370. This experience has deepened my understanding of how sensors interact with diagnostic codes in 1999 VW Passat 2.8L systems. The car now passes CA smog inspection without any active codes, and I expect it to remain reliable for at least two years. Hopefully, next time I’ll be able to diagnose these issues independently. Thanks again — Cheers, Ron

Anonymous 2010-05-13 06:10

Great to hear the issue is resolved! Thanks for sharing your full troubleshooting journey — it’s very helpful for other owners of the 1999 VW Passat 2.8L with similar codes.