Dtc code 18074

Hi All,

I have brought the wife a 52 plate a2 1.4 tdi(75) 125,647miles on the clock. I have had the cambelt and water pump changed, done a full service myself to save cost. But now I have a fault with the car,code is DTC 18074 cylinder one. I am going to replace the wiring loom for Cyl 1 as this is the cheaper option. I know its situated underneath the rocker cover, but can anyone tell me if cyl 1 is on the left or right side of the engine when looking towards the front of the car. I am planning to do this on Sunday, as im taking bits of the engine to get the rocker cover off I will also clean the EGR valve.

I will keep you guys posted on how I get on.

Hi Kully, welcome to the A2oc.
For info, cyl 1 is on the left side of the engine, with the cylinders always being numbered (starting with cyl 1) from the cambelt end of the engine.

On TDis the injector loom is a one piece assy so you can't just relace the wiring to individual cylinders. There is some info on replacement in this thread from the 'how to' section of the forum - http://www.a2oc.net/forum/showthread.php?20310-Diesel-Injector-Loom-Harness-Replacement

For the benefit of others, this is the Ross Tech description of fault code 18074 - http://wiki.ross-tech.com/wiki/index.php/18074/P1666

Cheers Spike

Hi Spike,

Thanks for the info, I have had a read of the info now. I thought it was individual wiring for each injector, i was wrong. Anyway wiring loom is on order from Halesowen Audi for £55inc vat. Should be here tomorrow and will tackle this on Sunday morning along with egr valve cleaning. What would you recommend i use to clean the egr valve anyway?

Cheers Kully

The only way to give the EGR valve a thorough clean is to remove it. Over time, the combination of oil mist and hot exhaust gases cause a build up of a thick tar like substance. Even with repeated scrubbing using degreaser and a stiff brush, it takes ages to shift, so I don't think any of the 'miracle' cleaners you spray down the intake will have much effect. On A2s it rarely seems to cause a problem so I'd just concentrate on the injector loom replacement and see how it runs.

Cheers Spike

Hi All,

I have replaced the injector wiring harness on the wifes A2, at first it seemed daunting, but wasn't too bad once I got started. It took me 6 hours to complete the job and the car is running very well.

The driver side head light is misting up quite alot causing condensation, I'm thinking of using a bead of clear bathroom sealant on the back plate. I suspect this is where the water is getting in.

Also the A2 is in for a o/s/f wheel bearing change, I brought a SKF hub/bearing for £50.50 from www.carparts4less.co.uk over christmas holidays. The labour is £55.00 at a local garage that specialises in all german cars. (Penn street autos, Wolverhampton). i think £105.50 all in isn't bad at all, what do you guys think?

Cheers

Kully

Well done for doing the loom replacement - sounds like you did a good slow and steady routine to get it done! I did it myself too, it seemed ridiculous to have to take things like the windscreen wiper and splash panel off in order to access the air-scoop in order to access the back of the head but I'm sure you enjoyed it!

That's a good price for a wheel bearing change I reckon.

With the headlight cluster, in the meantime it's worth dropping in a couple of sachets of silica gel into the headlamp cluster to help soak up the moisture.

I took my time as i didn't want to break anything or loose any bolts tools etc.... in the engine bay. The wheel bearing is now done and the noise has gone, feels much more comfortable to drive and so does the steering.

It must be difficult getting the silica sachets out again as the headlight unit does not come apart. Next job is to fit the new diesel filter, just never got round to it when I serviced the car last Dec 12.