EPC Light and Engine Issues: Requesting Help
bill_krishaan
Member Posts: 3
Hello all,
I'm reaching out for insights into a recurring issue with my 2018 Volkswagen Passat 2.0T R-Line Sedan, which has clocked 71,000 miles. I've owned it for a year, and it's been well-maintained since its purchase as a used, one-owner vehicle.
Issue Timeline:
Early November: The car started shaking, and the EPC light activated. A mechanic reset the EPC light but advised a check at a VW dealership.
Last Week: The shaking returned, and the EPC light came on again. A mobile mechanic suggested a potential issue with the third fuel injector or its wiring and recommended replacing all four injectors. Additionally, I noticed a change in idling when checking the oil, which was a quart low. I added fuel injector cleaner, high-octane gas, and a quart of oil. The car has been running smoothly since.
Current Concerns:
The car is currently operating fine, but I fear the EPC light and shaking may recur. I have an appointment with a local European car specialist, but I'm concerned about their ability to diagnose the root cause.
**Seeking Advice: **
Has anyone experienced similar issues with their Passat? What were the causes and solutions? I'm particularly interested in any insights into the EPC light occurrences and the potential injector problem. Any advice on avoiding unnecessary dealership costs would also be greatly appreciated.
Thanks in advance for any help you can provide!
K.
Comments
What you need is someone to analyze the problem while it is occurring. The trouble codes that get set during a failure do help point in a given direction but that doesn't necessarily become a diagnosis. A trouble code is the identification number of a test that a computer has run that has failed. Trouble codes don't tell the technician what part is bad again they only indicate what test failed. That being said have there been codes set and if so, what are they?
By your description the problem isn't present by the time you are getting someone to look at the car. They can clear the code and turn the light off but by then there is nothing to find. What a technician needs are details of the operating conditions, weather, and anything else that can be noticed that may help them run the vehicle and get the problem to occur.
Pay attention to things like:
How long/far was the vehicle driven when the problem occurred.
Was the vehicle driven, shut down and restarted? If so, how far/long was each trip and how long was it stopped for?
What was the weather when it occurs? Raining? Hot (above 80f) Cold (below 40f) In-between?
Was in being driven in town, or on the highway?
What options were being used, AC, Defrosters, blower speed?
The thing about tackling a problem like this is while there can be pattern failures, each vehicle still needs analyzed as its own unique event. Trying to reference what was wrong with another car without testing and proving what is happening this time is more likely to have a repair attempted that has nothing to do with your car's problem. Even trying to suggest a course of action based on some other event no matter how similar the symptom appears to be can oftentimes be a complete misdirection and end up wasting time.
One of my routines for very random or difficult failures is to have someone road testing the car while staying close to the shop. The moment it acts up they get to the shop as fast as they can, or I go to where they are ready to start gathering information and direction. In these cases, I would have already baselined the failure and laid out a test plan in advance. That way I can cover a lot of ground very rapidly and hopefully complete the testing before the problem goes back into hiding again.