# 1.8t swap mk2 coolant temp sensor/gauge issues



## ronster731 (Sep 25, 2004)

I followed wiring diagrams from the vortex, (#7 pin)

•Pin # T10m - Black Plug Description
◦2. Green/Blue > Tach/RPM Signal To MSD Tach Adapter - White
◦3. White/Gray > Oil Pressure Warning >G2/12 (Blue/Black)
◦6. Black/Yellow Engine Coolant Level Warning
◦7. Blue/Brown > Coolant Temp Gauge >G2/3 (Red/Yellow)◦9. Brown/Red Vehicle Speed Signal
◦10. Yellow/Red Leak Detection Pump


The only thing that happens is that my gauge pegs out at the top. If I give a ground to g2/3 the gauge does come down but lets back up when I release the ground. 

This is what I gathered from looking at both wiring. The old wiring (Digi) is a 12v system. If I hook up the old wiring to the coolant plug, it will work, but the AEB wiring requires the 4 pin wiring and the 4pin green plug. As I said before when it is hooked up it just pegs out at the top. From what I have learned the AEB is a negative resistance system to the gauge. So how is this supposed to work with my mk2 cluster. I don't know if the wiring is meant for the mk3 cluster. Any help will be appreciated as it seems that no one that has done this swap that wants to help me out here. Thanks in advance (if u post something useful). LOL.


----------



## ronster731 (Sep 25, 2004)

anyone.....anyone??????????????????????????


----------



## motorlager (Sep 26, 2005)

Well ok, you said anyone. Get an OBD2 mk3 2.0 ECT sensor and electrical plug. This will work better than the green plug with your mk2 gauge and still read correct to the ECM. Pin assignment is different. Pin 1 goes to the gauge. Ground pin 2. Pins 3 and 4 go to the ECM. I think. Let me check the wiring diagram. This is what i use for 1.8T with a stock vanagon cluster. The Gauge reads midway at 95 celsius and i have verified the ECM reading is correct with a temp probe in the cooling system.


----------



## ronster731 (Sep 25, 2004)

Hey, thanks for the reply... I am tired of :banghead:. Pretty much at a loss. I will give it a try. But just want to get clarification from you about the diagram. Please LMK. Thanks,:thumbup: Ronnie


----------



## zoidmk5 (Sep 17, 2006)

i would like to know about this diagram as well


----------



## motorlager (Sep 26, 2005)

If you have a 4 pin black connector that excepts the newer style 4 pin green or black ECT sensor (it has the rounded edge on one side of the connector, D-shaped)... you can splice a mk3 ECT sensor connector in by swapping pins 1 and 4. 

Pin 1 (1.8T) goes to pin 4 (mk3) 
Pin 4 goes to pin 1
Pin 2 goes to 2
Pin 3 goes to 3

This way pins 1 and 3 will go to the ECM, Pin 4 goes to the gauge and pin 2 will be sensor ground for the gauge. If pin 2 is not grounded already in the harness (depending on your wiring) you can ground it at the valve cover along with the coilpack grounds.


----------



## ronster731 (Sep 25, 2004)

What if I just have the stock AEB connector. It is not the D shaped connector? Do I still follow your diagram. LMK. Thanks again.:thumbup:


----------



## tongboy (Dec 13, 2001)

does your ECU display the proper temp in vag-com/vcds?

Sounds like you've got the wrong wire or are missing a ground somewhere.

I'd check the wiring diagram from your specific engine - they do vary a bit between years but the wiring diagram will be MUCH more useful than a few posts on the vortex in discovering why you're having issues.

you'll really want to leave the newer coolant sensor in so the ECU has the proper reading - You can run the mk2 cluster without any drama on the new sensor once you get it hooked up right.


----------



## motorlager (Sep 26, 2005)

I think the AEB may have the same pin assignment as the mk3 sensor as it has the same shape and excepts the same style sensors, but i will look into it. It does sound like pin 2 is not grounded. What are your wire colors for each of the 4 pins?


----------



## ronster731 (Sep 25, 2004)

motorlager said:


> I think the AEB may have the same pin assignment as the mk3 sensor as it has the same shape and excepts the same style sensors, but i will look into it. It does sound like pin 2 is not grounded. What are your wire colors for each of the 4 pins?


I have ground on all my wires except for the blue/brown. I believe they are brown, grey/white, brown/white and brown/blue. I can't say for sure, I'm at work right now. I can double check when I get home tomorrow.


----------



## sdezego (Apr 23, 2004)

motorlager said:


> I think the AEB may have the same pin assignment as the mk3 sensor as it has the same shape and excepts the same style sensors, but i will look into it. It does sound like pin 2 is not grounded. What are your wire colors for each of the 4 pins?



Here is what I had put together a few years back. ABA and AEb use same pin assignment, but the AEB will not work for you gauge w/o using an inline resistor. I forget which one was perfect, but in the end I used the ABA sensor (one with the Yellow Ring)


----------



## motorlager (Sep 26, 2005)

Thanks for posting that up. Good info :thumbup:


----------



## ronster731 (Sep 25, 2004)

looks like I'll just use the ABA sensor then. I'll post back up when I put it on. Thanks again for the info. :beer:


----------



## ronster731 (Sep 25, 2004)

Just an update for all interested. The ABA yellow ringed black 4 pin works perfectly as a couple vortexers stated. Thanks again for all the info. :beer:


----------



## d-bot (Sep 6, 2004)

Again, great information here. I did my swap into a mk1. No where in any wiring documentation from forum members or in project threads tell you about the ground wire from the red plug which is necessary for the sensor and gauge. Not sure why this isn't talked about more!

Either way, the ABA sensor worked like a charm as well while the AEB one was reading way too high. Thanks again for all the good info motolager and sdezego!


----------



## vwdirector (Jan 31, 2006)

Will this ABA sensor work with a AWP 1.8t and a mk2 ce1 cluster?


----------



## izcorrado18 (Aug 21, 2005)

Checkout my thread. I had the same issue. I used the ABA black with yellow stripe OBD2 coolant sensor and worked perfect. Not sure if it works for an AWP swap. I don't see why not except for the plug.


----------



## chrgdVR (Aug 2, 2004)

I used a resistor to get the gauge to read right. Can't remember what size it was. I had bought a bunch and just used the one that put the gauge in the middle when warm. 
This is with the early mk2 cluster and a mk4 cts 


Sent from my iPhone using Tapatalk - now Free


----------

