bluestraveller

This sounds unreasonable. If the TDI engine is certified for something tighter than generic ULSI standards then we're all in trouble. Perhaps you should call the Audi toll free number and complain.

DUTCH VanAtlanta

Sounds like a dealer service department blowing smoke to mask their ignorance.

kristatos

My CEL ('10 TDI) came on at roughly 1300 miles and I will take it in this week to have the local Audi service dept look at it. My wife's A4 Avant (gasoline engine) had the CEL come on pretty early on and they reset it and then it never came on again. We'll see what happens with the Q7.

Wouldn't most diesel come from the same refineries? I find it hard to believe there is any difference from the diesel 2 at one station to another as some have posted here. Sounds far-fetched to me.

kristatos

Turned out that the Adblue temp sensor went bad causing the CEL to go on and so it was replaced and I was on my way. Tech said it was a rare thing to have happen so early on. Anyways, they drained the Adblue tank and filled and leveled it so overall it seems all is good for now.

One thing they said when I first called in with the CEL issue is that if the CEL comes on and stays on it's a "driveable" event. If the CEL is flashing then avoid driving it. I wonder if the car goes into a limp mode or something if the CEL is flashing?

Cottonmouth

My CEL came on and the dealership told me it was "the knock sensors". Them told me it would cost $1500 to fix. Sounds like horse**** after reading this thread.

If that's true then I won't be bringing it to the dealership ever again.

As far as I can see, these sensors are only $70 a piece approximately. Plus labor. Anybody replaced the sensor themselves or know where to find a DIY for this?

smith2010Q7

Welcome back. Your thread is total different than the CEL light for NOx sensor. you might need to start a new thread.
Cel lights have over 200 codes store in the TCM, and ECU which your knock sensor has its own code.

info on a knock sensor:

The knock sensor was designed as a listening device for the vehicle's engine. It is used to detect engine noises such as detonation, when fuel ignites in an engine's cylinder, as well as adjusts the ignition timing when the vehicle is being driven. When a knock sensor is not working properly, it may cause permanent engine damage. Therefore, there are various symptoms to aid in recognizing a faulty knock sensor.

Check Engine Light

One of the main symptoms for a faulty knock sensor is the"check engine" light that will begin to flash on the vehicle's dashboard. This can be caused by the grade of gasoline being used; using cheap gasoline causes detonation and triggers the engine's main control board to wrongly diagnose the sensor. This will send a false malfunction message in the form of the check engine light. Before consulting a mechanic, try using a higher grade of gasoline. This can solve the problem.

Engine Noises

Sounds coming from the vehicle's engines are another sign of a faulty knock sensor. When the knock sensor is going bad, the driver may hear a pounding noise that becomes louder with time. This is caused by fuel and air igniting inside the cylinder instead of burning evenly before the sensor in its correct position, also known as pre-ignition.


Additional Symptoms

There are various other symptoms to determine a faulty knock sensor, such as fuel economy. The vehicle will use and burn more gas and require more frequent fuel replenishment, which will affect fuel economy. Detonation in the cylinders may cause strong burning smells coming from the engine, as well as exhaust smells. Often, the vehicle will have trouble accelerating. Hesitation from the engine during acceleration may appear.Another common symptom is a vibration or misfire when the engine is being started, because of a sluggish engine.