10 replies to this topic

[doublefacy]

Hi,

Car: golf mk4 pd150 tdi
Out of nowhere  I suddenly got this issue where I have triangle with exclamation mark warning light on, kinda the one that shows when switch ESP off.

This time it just stays on , so I connected VCDS and got these 2 error codes:

Under Engine section:
17569 - Manifold Temp Sensor (G72): Open or Short to Plus
P1161 - 35-00 - -

Under ABS section
01314 - Engine Control Module
013 - Check DTC Memory

So I suspect issue with MAP sensor where i got 4 wires , I guess 2 for pressure and 2 for temperature.
Pressures works fine - at least reading are plausible and car drives ok, at least to shop and back.

All I found is that its either wiring or sensor itself is faulty.

Wondered if anyone know how to test sensor, specifically for temperature. There seem lots of video how to test pressure and the Voltage should be ~4V and drop when vaccum applied.
But how do i test temperature side. I mean apart from blowing hot air and checking readings, but reading can be wrong because of broken wire or something.

VCDS showed me 140C when car was cold, which I would expect to be wrong as turbo is not yet warmed up enough to affect anything.

Is there some Resistance readings I could check against or something. Obviously new sensor is not expensive  ~£20, but if the issue is not in sensor wouldnt want to buy for sake of making sure.

 

Any Ideas?

Thank you

[ttg4l]

With the car off, but ignition on, I believe intake temp should show as ambient temp.

What does yours read?

[adam-]

It's open circuit.  Short it out and if you get a new code, the sensor is dead and the wiring checks out.

[doublefacy]

It's open circuit.  Short it out and if you get a new code, the sensor is dead and the wiring checks out.

Thanks for advice, just wondered out of those 4 wires which ones i need to short? Is it 2 and 3? Just lot of videos show to measure pressure by checking voltage across 1 and 4, so i assume 2 and 3 would be for temperature.

Like I said it seem to measure pressure ok.

[doublefacy]

I found this diagram:


Not sure if MAPs can have possibly different pinout, but I would thing they all built by same principle.

According to this diagram should I short Pin 3 and Pin 4 then? To check temperature side of sensor?
I can first check what voltage i'm getting between 3 and 4. I would assume ECU sends some voltage and temperature sensitive resistor changes it and based on change it works out temperature

[doublefacy]

PROBLEM FOUND!!!

It was damaged wire, probably from vibration. It wasn't secured very well and since running SMF, car has extra vibration.
 

Btw diagram above is not correct for golf Mk4, at least my model. I found out that pressure readings get sent via 3 pin, cause I knew my pressure reading are working ok and by measuring voltage across pins I only got reading between 3 and 4, assuming 4 is ground.

When disconnected with ignition on it was reading 5V
when connected and ignition on it was reading ~4V
when engine started and connected =>  ~3.3V

Since my intake air temperature in VCDS (group 7 , 3rd box) did not change when plugged in or unplugged , stayed 135.9 C . I knew that those 3 and 4 pins are not for temperature.

So I started to strip back cable to investigate wires as far as I can get without removing parts.

Here are some photos:

As seen in pictures 2nd pin wire is completely rubbed apart and 3rd is partially damages and some wearing on 1st as well.
Will have to do some soldering tomorrow.
 

 

[thinkpad]

Great stuff! Always nice when it's a cheap repair.

[Imagewerx]

Your post has been moved.Always ask technical questions in the relevant technical section.They really are very easy to find.

[adam-]

Again, this is nothing to do with diesels.  Fault codes in general, so would be engine or related.

[thinkpad]

Again, this is nothing to do with diesels.  Fault codes in general, so would be engine or related.

HAHA
It could go under Engine category or the electrics category - take your pick! That's why things always get posted in wrong category, even mods don't know where to put it. The zillion categories are pointless!

[doublefacy]

I agree that too many categories dont work well. Reason for me posting under general was hoping to get more views and possibly solutions.
Out of my own experience I dont go through all those many categories when i pop in this forum from time to time, I usually just take a look at general section.

Maybe I'm a bit thick, but i never seem to find what i'm looking for. Like for this issue I found same fault codes being discussed on tdiclub forum and even there was no solution, cause guy discovered same issue of rats had chewed his wires.

But information about  how to properly test sensor or which pins mean what, cant seem to find it.
 

My friend/ mechanic used to have access to autodata, I believe there you can see all the diagrams and pins for plugs.
This is why i always try to update my threads with solution, so if anyone ever got this issue they got at least things they can test.

Btw i FIXED it today !!! Happy time
I soldered to damaged wires , warning light on dash disappeared. Connected VCDS and cleared both faults - all good , didnt come back.

Checked temperature where i used to check before, under Engine Measuring blocks Group7. Showed 28.5C, which is what i expected considering I drove it minutes before, so engine was warm. Plus reving a bit it started to go up a bit.

 

So yeah back to faultless golf