Case Study: VW Jetta MIL on with no drivability issues

July 28, 2022

The customer brought his Jetta into the shop because the malfunction indicator light (MIL) was on. There were no obvious drivability issues.

Richard Diegle

Related To:

ALLDATA

Vehicle: 2016 Volkswagen Jetta Sedan (163), L4-1.4L Turbo (CZTA), Automatic Transmission/Transaxle

Mileage: 122,368

Problem: The customer brought his Jetta into the shop because the malfunction indicator light (MIL) was on. There were no obvious drivability issues.

Case Details: The technician connected a scan tool and pulled the following seven diagnostic trouble codes (DTCs):

P2279 - Intake Air System Leak
P1250 - Fuel Level Too Low
P0300 - Random misfire detected
P0301 - Cylinder 1 misfire
P0302 – Cylinder 2 misfire
P0303 - Cylinder 3 misfire
P0304 - Cylinder 4 misfire

With this many DTCs, the technician thought it would be best to call ALLDATA Tech-Assist for some diagnostic advice. The Tech-Assist consultant suggested reviewing a technical service bulletin (TSB) # 01 15 28 in ALLDATA. In it, VW says that if DTCs P0301 - P0308 (Cyl.1 Misfire Detected - Cyl.8 Misfire Detected) are accompanied by P1250 (fuel level too low), it’s likely the faults occurred due to low fuel level and not a component malfunction.

Confirmed Repair: The technician spoke to the customer who confirmed the fuel tank was run low several times. The DTCs were cleared by the technician who then filled the fuel tank and went for a test drive. The DTCs did not return, and the MIL stayed off. He released the vehicle to the customer who reported a month later there were no further issues. Problem solved!

Reprinted with permission from ALLDATA.

About the Author

Richard Diegle | Senior Automotive Editor for ALLDATA

Rich Diegle has been in the automotive industry since 1978. After graduating from a local community college, he began working at a Nissan dealership as a used car technician. Since then, he’s worked as a Nissan and ASE master automotive technician, shop owner, marketing copywriter, automotive editor, public relations manager, instructor, ALLDATA Tech-Assist team manager, and a senior automotive editor.