Skip the auto shop - Our mechanics make house calls

Q: EPC Light is on - 2011 Audi A4

asked by on

When I power on my car it starts shaking. I saw it is because the engine shakes a lot. The issue started 2 days ago, I was driving for 5 minutes, then the Check engine light started flashing then the EPC light got On. I had trouble to accelerate. I decided to go back home and park the Car. Yesterday I turned my car on again. The engine starts shaking in the same way. Then I turned it off.

My car has 70000 miles.
My car has an automatic transmission.

A: Hi there. While driving the vehicle and hav...

Hi there. While driving the vehicle and having the engine light begin to flash, then there is a major problem that is currently existing. When the EPC light comes on, there is an issue with the throttle pedal, throttle body, traction control, or cruise control.

Due to the nature of the engine shaking while both lights are on, this would be due to a loss of fuel or a high volume of fuel to the cylinders. Most likely, the throttle pedal has lost communication to the computer and the computer is trying to determine what the count is on the pedal. This put the engine into a limp mode and make the fuel system either go lean or rich depending on the counts on the throttle pedal.

Unplug the harness to the pedal and put a digital ohm meter on the terminals to the pedal. Check resistance on the pedal with it up and then check resistance with the pedal down. If there is no change, then the throttle pedal needs replaced. If there is a change, then the throttle position sensor needs replaced on the engine.

If you need further assistance troubleshooting your vehicle, then seek out a technician, such as one from YourMechanic, that can perform these tests and properly diagnose rough running engine at your own location.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: engine using oil

I would say that is not normal. Especially after a fresh rebuild, unless only the bearings were changed and nothing was done to the piston rings. On your engine, it is common for the piston rings to get gummed...

Q: how often do i need to get my oil changed

Hello there, thank you for asking about your 2010 Hyundai Genesis Coupe. The service manual calls for the oil and filter to be changed every 3000 miles. If you would like help changing your oil and filter, have a technician...

Q: Car goes into gear but won't move. Oil leak after hitting dip

If the tires won't turn, but the car will go into gear, I would first check that the parking brake is not enabled, keeping the vehicle from moving. If that is not the case, I would then recommend having a...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...