By common ground what do you mean? Grounded to the chassis? There is a ground point bang next to the sensor that i can see. Thanks
Having checked it pin 3 on the sensor should get voltage from ecu from pin 33. Ecu diagram here https://drive.google.com/open?id=0B2YUpJEMHSDrZDEzOGNiZGMtZGM1Yy00MGIyLWE2MWEtZjExZTg2NWVkZmFl
The simplest way is disconnect the ecu connector and the temp sensor connector. You should have a circuit between ecu connector pin 33 and pin 3 of your temp sensor. And a circuit between pin 14 and pin 1 of the temp sensor. Although from what I can see some ahu's maybe had the temp sensor pins swapped... Pins 2 and 4 are connected to your clocks.
Ok great. I now have a multimeter that checks continuity and also a test light so I'll have a crack at it tomorrow.
Ok so been out and done a continuity test. Pin 1 temp sensor continuity to pin 33 ecu Pin 3 temp sensor continuity to pin 14 ecu Test light results to follow next....
I'm not sure but I'll try and dig it out from my email receipt. One weird thing though is that I have an earth at the ecu side of the round screw-on engine connector but no earth at pin 1 when it's connected. There are no visible breaks between connector and sensor plug! Test light also shows there is no power to Pin 3 at all with engine on or off. Haven't tried with engine running. This suggests there is no power from wherever ecu pin 14 gets it from?
Ok things get more difficult to understand! I've plumbed the AHU ecu back in to see if it changes anything with the engine temp sensor and it doesn't. BUT...the engine now idles as normal at 903rpm and I'm not sure how this is possible but the turbo actuator is moving in the right direction! I'm getting readings on the boost gauge when throttle applied too. Did any AHU motors have vacuum actuator? I'm confused as I'm sure this ECU shouldn't work the pd150 actuator! I may take for a quick test drive see what's happening.... I just test drove it up and down the street and the turbo definitely kicks in! Boost gauge shows some boost too! What the hell! No change with temp sensor though
With AHU ecu the duty cycle is around 98% at idle and drops under throttle in neutral. With AFN ecu the duty cycle is around 24% at idle and rises under throttle in neutral. I struggle to understand what is normal so any help would be much appreciated. Thanks.
sounds like you have an intermittent fault in the wiring harness, is the round engine loom plug fully locked? check both pins at the temp sensor, round plug and ecu for any signs of corrosion and wire damage to the rear, also check the pins are not bent out of shape or pushed backwards in the plug housings. try to chase your loom as best you can from sensor to engien, might have a bad joint or chafed wire somewhere. clear the codes, check the coolant temp measuring block in vagcom from cold and while warming up. make sure sensor is reporting sensible values and not dropping out periodicaly.
The round plug I took out of the bracket and zip tied it tight shut so it is 100% together properly. Possible that there is a bent pin but I had continuity from pins 1 and 3 right through to the ecu connector earlier with the round plug connected. What gives ecu pin 14 it's power?
its internal to the ecu, as i say check the wirting over carefully then plug it all back together and look at your ecu measuring blocks
Righty. When I move the circular connector around (out of the bracket) it cuts the engine out and gives fuel cut off solenoid code. I'll get it all back in as it's meant to be and check for bent pins but unfortunately the clip that spins on and locks it in place had some broken bits and now does sod all...not happy! I'll see what I get.
