NefMoto

I recently purchased a 2003 allroad that was throwing codes for the egt sensors. I searched around a bit and found that some people have been able to successfully repair their egt sensors by resoldering the 5 solder points inside of the sensor. While this seems to have worked well for one of my sensors, it did not work for the other. I still received the following code, immediately after clearing it:

17861 - Exhaust Gas Temp Sensor 1 (G235)
P1453 - 35-10 - Open or Short to Plus - Intermittent

So, I figured I was going to have to fork over the $250 to buy a new EGT sensor, which by reports, would probably have a similar fate a couple years down the road. Instead, I did a little searching and found a thread where a guy replaced the circuit board (pcb) of the egt. The intent was so he could have a real time reading of his egts in cabin. I'm not going for real time readouts here, but just want to fix my egt sensor, and slap my car out of limp mode. So, with a little more searching, I found a guy in Poland who makes a replacement boards for these egt sensors. I was able to contact him through email, sent a paypal for $45, and received the new egt pcb in the mail a week later. Great service, fast shipping, and a cheap price for what I hope is a permanent solution.

Time for a mini DIY:

First, it's best to remove the senor from the car completely. For the driver's side, it might be better to get do this all with the probe attached to the exhaust, since it's a real bugger to remove.

Open the box of EGT sensor. There's a bunch of slimy silicone that was used to protect the board. Remove all of this junk. I used a toothbrush to remove what I could.
Once you've removed as much crap as you can, you'll need to remove the circuit board from the box completely. You can use a solder gun to melt the solder and remove each leg one by one.

After the pcb has been removed, get the rest of the box as clean as possible. I used some engine cleaner and let it sit for a few minutes to break down the rest of the silicone. I then blasted the box with compressed air to remove most of the remaining junk, followed by a light wash down with brake parts cleaner. I then cleaned up the leads as best as I could to remove any extra solder. I mostly needed to do this because I attempted to fix the unit by resoldering the legs first.

Here's what the box looked like before soldering the new board in:

(http://i567.photobucket.com/albums/ss118/sbloom/Cars/egtcleaned_zps7c68155f.jpg)

Next, solder in the new board. This is pretty easy, just make the wires find there way home in the middle of the leads.

(http://i567.photobucket.com/albums/ss118/sbloom/Cars/egtnewpcb_zps9f562053.jpg)

Use something to secure the board to the box, double sided tape, dab of rtv, whatever. I used rtv silicone to seal the box shut again, and held it together for an hour or so with a clamp, and reinstalled. Note: I did not encase the pcb with silicone like it was from the factory.

I started up the car, cleared the codes, and to my pleasure, the codes did not return!!!! SUCCESS!!! WOOHOO!! I also took some logs with vagcom, and where the ECU was only ever requesting 6-7lbs of boost before with the egt codes, it now is requesting 10-12lbs and my car has lost the sluggishness it most surely gained when the egts failed.

And finally, here's all the information you need to know about how to order the new circuit boards.
I was able to contact him via these emails:
sidaudis4@gmail.com
sd110@go2.pl

(http://i567.photobucket.com/albums/ss118/sbloom/Cars/egtcard_zpsb8123406.jpg)

Here is part one of EGTs PCB with LED, Wideband , STE-PPD install plus re-purposing the center visor . With tips some might find handy. Warning long and lots of images.

(http://www.intocco.com/images/egt1.jpg)


(http://www.intocco.com/images/egt2.jpg)


Remove all covers as it will make it easier to solder in the engine bay and you won't crack anything by leaning on them.

(http://www.intocco.com/images/egt3.jpg)


Remove intake, y-pipe and un-attach the coolant overflow tank and flip it out of the way.

(http://www.intocco.com/images/egt4.jpg)


the EGTs are bolted to the back of the manifold. Remove the harnesses and weave the cases out so you can place them on top of the manifold. We will be soldering them in place so there is no need to remove the thermocoupler from the manifolds.

(http://www.intocco.com/images/egt5.jpg)

(http://www.intocco.com/images/egt6.jpg)


This is where you need to insert a screw driver to crack open the case. It is farly brittle so take your time we will need this intact.

(http://www.intocco.com/images/egt7.jpg)


Interesting to note the OEM PCBs. The one on the left is not working and you can see the areas where there is corrosion on the soldered leads and on the PCB itself. The board on the right is functioning and notice that there is no corrosion and all solder points are clean and shiny. I have tried to re-solder EGTs in the past with marginal success. I am sure the reason for that is the flaws in some go further than just the main connections. Good thing we are replacing the boards entirely.

(http://www.intocco.com/images/egt8.jpg)


Now it is time to remove the Gel and the OEM PCBs from the sensor housings. This shit is a nightmare.

(http://www.intocco.com/images/egt9.jpg)


Once all the gel is all out it is time to solder in the new boards in place of the OEM boards. There will be two additional leads on for an additional sensor output that will be run to the LED displays and to devices like the STE-PPD and a ground. I chose to install proper harnesses with micro amps connectors & heat shields so they could be disconnected for engine pulls. Probably a good practice for anything you hook up under the hood of these things because as you all know the engine is going to  come out at some time might as well make it easier.

(http://www.intocco.com/images/egt10.jpg)


I then secured the PCBs in the cases with MG Chemicals RTV Silicone Adhesive Sealant. This is the low odor stuff made for electronics. Do not use any old silicone. If Audi used this stuff on the original PCBs I bet I would not be writing this DIY

(http://www.intocco.com/images/egt11.jpg)


Now while the silicone is setting up its time for some takeout.

(http://www.intocco.com/images/egt12.jpg)


I adopted to run another harness for the addition of the STE-PPD Boost Controller. It is a good idea to run as much of the wiring as you can think of because it is much easier once everything is all opened up. Pulling one wire is as hard as pulling 10.

(http://www.intocco.com/images/egt17.jpg)


Now it is time to cut the grommet on the firewall and cut the grommet on the main wiring harness as it enters the ECU weatherproof container. The ECU grommet has four spaces right above the wire bundle that with a little working can be made to accommodate the three harnesses the vacuum line and the wideband cable.

(http://www.intocco.com/images/egt13.jpg)

(http://www.intocco.com/images/egt14.jpg)

(http://www.intocco.com/images/egt15.jpg)


Once all the wiring is through the ECU box you feed it through the back into the cabin. This is after you remove the kick panel under the steering column. Lots of info on this if you have never done it. Just search hear or Google it.

(http://www.intocco.com/images/egt16.jpg)


As this is a three part DIY there is one common harness used by all three components. I made up this harness out of the harness from STE for the Wide band port on the PPD, the harness for the Zeitronix ZT-3 controller and a fused harness that will provide ground and switched 12v for the ZT-3, the two LED displays and the wide band O2.

(http://www.intocco.com/images/egt18.jpg)


I then tested the displays by temporarily wiring them up inside the cabin. Everything OK.

(http://www.intocco.com/images/egt19.jpg)

Now for finding out where to put the LEDs. Along with sensor output from the Left and right banks there was ground, 12v switched power and a light switch controlled power to aid in the dimming function. I initially attempted to put it in the rear view mirror but i didn't like the distraction the LEDs caused. This method is doable for any variety of displays but that is for another DIY. I opted to try putting them in the middle visor.

I cut the fronts with a sharp Exacto knife to the exact size of the displays. I positioned them tilted to the drivers view. They were then hot glued into place. The backs were cut to alow for the LEDs to protrude out the back and be soldered in place.

(http://www.intocco.com/images/egt20.jpg)


I then tapped up the front and back to get ready to fill in any gaps and truly integrate the LEDs into the visor. I used a flexible two part putty used for spot repairing automotive bumpers and trim. Once sanded  It was now off to the "spray boof for cheap ass bastards" for a prime and a coat or two of Duplicolor Trim paint. This stuff is great because it finishes with a texture matching the OEM plastic.

(http://www.intocco.com/images/egt21.jpg)

(http://www.intocco.com/images/egt22.jpg)


Back from the Boof. I covered the back with a thin neoprene in flat black. I used double sided tape to fix the neoprene.

(http://www.intocco.com/images/egt23.jpg)

(http://www.intocco.com/images/egt24.jpg)


I then removed the air bag cover button on the driver side column to reveal the one torx screw that with two clips are the only things holding the cover in place. Just gently pull the cover away. Keep in mind there is an airbag in there. Its best to take off your Corduroy  pants if you have Alcantara seats. No Sparks! Feed the 5 wires up through the pillar, zip tie it as you go. tuck it along the headliner and attach the leads to the visor. Once again I used AMP style micro connectors. Screw the visor back in.

(http://www.intocco.com/images/egt25.jpg)


The last thing was finding a tap for the light switch controlled power to control the dimming function of the LEDs. Another key function that is available when this is hooked in is that by turning on and off the lights 3 times puts the displays into configuration mode.  This allows for the changing of the brightness of the displays and set the alarm threshold of the buzzer if you choose to install one. The default is set to 1000 degrees.

I chose to wire the lights controlled power to the drivers side vent wheel as it is the closest  source to the all of the other wiring.

(http://www.intocco.com/images/egt26.jpg)


Now just button all the panels back on the kick pad and fuse panel and you are done part one of this three part install.

(http://www.intocco.com/images/egt27.jpg)


This DIY was sponsored by (http://www.intocco.com/images/dead_bird_small.png) and Captain Morgan Black Spiced Rum

Products used in this DIY

EGT PCBs and LEDs:

http://sidmotorsport.pl/pl/search?orderby=position&orderway=desc&search_query=egt&submit_search=http:// (http://"http://sidmotorsport.pl/pl/search?orderby=position&orderway=desc&search_query=egt&submit_search=http://")

Wideband: part 2

http://http://www.zeitronix.com/Products/Zt-3/Zt-3.shtml (http://"http://http://www.zeitronix.com/Products/Zt-3/Zt-3.shtml")

PPD: part 3

http://www.getste.com/ (http://"http://www.getste.com/")

We were literally talking about trying to figure out how to repair EGT's and now this. Awesome info..Looks like they are already out of stock  :'(

Also they have adapters for $3 each if you wanna run coils without output stages.

90 percent of the time it's the board.