Audi A4 (B8) - intermittent power loss, glow plug light flashing, engine light on

bobbytables

Hey Folks,

My A4 (B8, late 2008 model, 2.0TDI) has never given me any real trouble, so I'm concerned regarding these lights that have illuminated on my instrument cluster over the past 24 hours. Over the last few weeks I noticed that sometimes when I switch off the ignition, the engine shudders to a stop (shaking the car, not violently, but rougher than usual). Then a few days ago while cruising along and holding the rev at around 1800rpm, it felt like the it dipped down a bit and then climbed again all within a second or so by itself (like I temporarily lost some power). I didn't think too much of it and it didn't seem to happen again. At the time I wondered is my turbo failing, but it didn't happen again and I am used to feeling the turbo kick in as I drive.

Then yesterday evening I was idle at traffic lights on a slight incline, the revs started to dip below the usual 800rpm when idle to the extent that I thought the engine would cut out. So I revved it a bit and pulled in as soon as I got through the junction. It didn't repeat, but I happened to be right beside my garage (bit of luck) and they ran a diagnostic saying that the throttle body should be replaced. So I booked it in to have that done in the coming days. The mechanic said I should be fine to drive for the weekend and off I went.

Then a few hours later I started the car and drove about 100 metres and noticed the glow plug indicator started to flash every few seconds. On the TDI I believe this refers to the engine management system. Now I started to get worried, but at the same time apart from a light flashing every few seconds the car was driving as normal. Then this morning I started the car and both the engine light stayed on and the glow plugs light flashed every few seconds. Throughout this time no message was displayed on the instrument cluster.

I drove about 5 miles with the car driving normally and stopped. When I shut off the ignition the car didn't shudder as it sometimes did. When I got back in, I started the car and the engine light has stayed on, but the glow plugs light has remained off, and has done so now for the last 2 trips today.

I was reading online last night that this issue is quite common, but what has me worried is that many people report everything from a simple brake switch (due to wiring) to the throttle body being replaced as a fix, but many others report the issue coming back after a few days.

The DPF indicator hasn't illuminated at any stage in this car, and I take it for a run out the motorway every 2 - 3 weeks, apart from that it's city driving. Also timing belt was changed 15k miles ago.

Essentially I want to try and avoid numerous visits to the garage and incurring significant cost over the coming weeks. Although I do like my A4, I would have no problem returning to something more reliable if this is going to be a longwinded and costly fix.

Do you think the throttle body replace should sort this, or do you think that's only the start?

crasy dash

You should contact George Dalton on here real expert with vag cars .

He will probably read your thread anyway and post a reply and help

I replaced the throttle body on my 2009 a4 last year threw up a eml twice so I knew it wasn't going away replaced it and car is fine since

bobbytables

crasy dash wrote: »

I replaced the throttle body on my 2009 a4 last year threw up a eml twice so I knew it wasn't going away replaced it and car is fine since

That's good to hear.

Did another couple of spins since last post and all going well apart from engine light still illuminated. Paid close attention to idle revs when stopped and they're very consistent at 800rpm.

Read that the shudder during shutdown can be caused by wear on the anti shudder valve. With a name like that it sounds like a bit of one stop shop. I suspected some rubber mounting. However I have been fully depressing the clutch during shutdown as I believe it can also be associated with the DMF. Clutch in car seems fine, no shudder when moving or shifting.

Willmay12

I know this was years ago but I’m having exact same issue as you described. Did you ever get a fix?