mshan

I previously posted about a suddenly developing engine shaking with blinking check engine light.

These helpful forums said the problem is most likely a faulty ignition control unit, so I bought and just replaced a replacement part (Huco 4D0 905 351; same part number as is currently in my car).

Now it seems like a very simple swap out, but what is the white thermal grease stuff for? Do I place it on pins before reconnecting, or do I put on on outside of connections once I've reconnected new part?

pac1085

it is very simple, unbolt/unplug old one, and install new one.

when you take the module off, you'll see it's mounted to a heatsink which goes into the airbox... you put the heatsink compound inbetween the ICM and the heatsink..you'll see it when you pull the old one off..

mshan

And I take it the chassis itself has screw notches so you don't need a nut from underneath chassis?

And do the washers go on top of ICM, or between ICM and car chassis?

pac1085

i haven't done it in a long time, but you have nothing to worry about - it's a 5 minute job at most.

Ertman

washers go on top....

mshan

Replaced the ignition control module successfully.

Started up engine and the coarse engine shake is now gone (car now seems to idle and drive smoother than it did before problem started).

Now the check engine light (which had been blinking yellow) is now a solid yellow color.

What does this mean?:
- will it go away by itself over time
- does a mechanic have to reset the warning light
- do I still have some other problem that needs to fixed so that I don't risk damaging the car


My car is a 1999 A4 1.8TQ manual with 54,000 miles on it. Timing belt was replaced by dealer less than miles ago. Sudden engine shake and blinking check engine light developed less than a week ago when I was driving back from post office. This drive was less than 3 miles and about 5 minutes of drive time; car hasn't been driven since then (restarted engine once when I got home to see if problem would go away). Spark plugs were replaced electively about 2 years ago (somewhere in 30000 mile odometer range).

pac1085

drive it a bit, it should go away...if it doesn't take the car to autozone or advance auto parts or whatever is local to you, they can clear the codes.

mshan

I was just googling and one generic non-Audi thread on some other website said to hold down odometer reset button, then turn ignition on (don't have to actually start engine) till it light starts to blink, and that should reset check engine light.

qfrog Ti20

Either of those will necessitate a throttle body adaptation.

Ertman

ahhh, no