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.

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.

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