G28 Sensor wiring

[wilsonian]

Hello,

 

I'm hoping someone can point me in the right direction. I need to test the wires that feed the G28 sensor coming from the EU at the bulkhead. I've disconnected the Sensor and currently get 480ish Ohms which the haynes says is correct but there is no mention on where the wires go to the ECU.

 

Any help would be greatly appreciated as the car can't rev above 3500rpm ATM.

[Breezy_Pete]

Pin 1 of sensor connector, white wire, to pin 110 at engine ECU;

Pin 2 of sensor conn, brown wire, to pin 102 at engine ECU;

Pin 3 of sensor conn, black wire, commoned to other screens in engine wiring harness, should go to engine ECU pin 101 via a brown/white wire at that end.

[wilsonian]

thanks for the quick reply. I'm tearing my hair out as to why this fault is popping up!

[sparky2]

Hi Wino, Thanks for the reply, I tested the socket for G28 and found pins 2+3 shorted, I then removed the loom and found that pins 2 + 3 are joined 6 inches below the smaller ECU plug and go to pin 102 as a brown/blue cable with pin 1 going to pin 110. So after assuming the loom was faulty it should work.ps I tried to find a circuit diagram but failed, cheers Stuart

[sparky2]

It turned out to be the G28 camshaft sensor after all (grey plug) behind oil filter ! we checked the wiring and that was fine (see update above) to gain access to the sensor undo the large nut under the oil filter for the cooler (some oil leaks out) and gently prize out the sensor in the engine block, ours broke the top off so we managed to remove the plastic sleeve that was left with a 16mm rawbolt inserted just inside and just nipped up, and with a open ended spanner against the engine levered the bolt out with the plastic attached . We had a look inside the hole with a mirror and you could see the metal segments that trigger the hall sensor and they looked fine. We bought the G28 off e-bay (half dealer prices) and you could see the original VW numbers had been rubbed out so a genuine part. cheers - Stuart

[Breezy_Pete]

Cam sensor is G40, not G28.

[wilsonian]

He's getting confused, it was the G28 crank sensor The sensor was Febi model.

[Sebsebworcester]

Hi sorry to revive an old topic but im having exactly the same issue. Wires 2 and 3 are joined together couple of inches below the ecu, or so they appear . I've already replaced the sensor twice (Delphi + HAAS ) none of them would work. Is it normal for 2 and 3 to be shorting together? I've run a continuity test on them and they're buzzing together. Any help is greatly appreciated

[Breezy_Pete]

What year is the car, and what engine code?  Not sure why I didn't ask the OP the same questions

 

This is what an AMF-code engine's crank sensor wiring looks like, so if that's your engine, yes it is normal to see that link, shown as F27 below:-

 

Edited 3 September, 2018 by Wino

[Sebsebworcester]

Sorry, forgot to mention that. 2004 AMF code. So that rules that out. I assumed it has to be smth electrical because 7/10 times when I turn right, but never when i go straight or left , the engine completely cuts out RPM drop to 0  as if its turned off oil pump comes on. I then have to push the clutch in and it comes back. It won't do it stopped ie i can turn right left with no effect. I really don't know what else to look for. 

Edited 3 September, 2018 by Sebsebworcester
full expl

[Breezy_Pete]

It does sound like something is making/breaking a (vital!) circuit with cornering forces. Maybe check that the engine ECU connector(s) are fully latched in place, and check battery clamps for tightness?

When you do find the cause of the misbehaviour, please do let us know what it turned out to be.

[maccy]

I don’t want to be the harbinger of doom,but my old Fabia with a 1.4Tdi engine had exactly the same thing and it took forever to find it.The car eventually stopped totally and had to be recovered.It turned out that the crankshaft thrust washers were so worn,the one nearest to the flywheel fell out and the crank moved away fromthe crank sensor.It had also damaged the reluctor ring.The garage that fixed it took the sump off,straightened the bent reluctor ring and fitted a new set of thrusts and the problem was sorted.It happened twice that the car stopped for no apparent reason and then just started again .You really need to check the end float on the crankshaft ASAP.The first time it happened I hadn’t had the car very long and I always wondered if that is why the car was so cheap to get rid of it.

[Sebsebworcester]

It's back at the garage as I'm out of ideas to try and frankly getting tired of it now. I will try the above if they come back empty-handed. I will be back with a root cause once it's resolved. Many thanks for the advice. Maccy did yours have similar symptoms ie turning off when cornering or just iddling/ throttle cut-outs ?

[maccy]

20 minutes ago, Sebsebworcester said:

It's back at the garage as I'm out of ideas to try and frankly getting tired of it now. I will try the above if they come back empty-handed. I will be back with a root cause once it's resolved. Many thanks for the advice. Maccy did yours have similar symptoms ie turning off when cornering or just iddling/ throttle cut-outs ?

 

Mine switched off totally on cornering only.If I remember correctly on left handers.

[Sebsebworcester]

On 04/09/2018 at 16:38, maccy said:

I don’t want to be the harbinger of doom,but my old Fabia with a 1.4Tdi engine had exactly the same thing and it took forever to find it.The car eventually stopped totally and had to be recovered.It turned out that the crankshaft thrust washers were so worn,the one nearest to the flywheel fell out and the crank moved away fromthe crank sensor.It had also damaged the reluctor ring.The garage that fixed it took the sump off,straightened the bent reluctor ring and fitted a new set of thrusts and the problem was sorted.It happened twice that the car stopped for no apparent reason and then just started again .You really need to check the end float on the crankshaft ASAP.The first time it happened I hadn’t had the car very long and I always wondered if that is why the car was so cheap to get rid of it.

Just an update in case anyone is struggling with similar issue. The garage have put a camera through the crank sensor slot. 3 of the teeth on the reluctor ring/wheel are bent and as such they are taking the sump off to try and streighten the teeth. I will come back with an update once it s done.

[Breezy_Pete]

46 minutes ago, Sebsebworcester said:

3 of the teeth on the reluctor ring/wheel are bent

Wonder what caused that?

[Sebsebworcester]

Good question. They said they will check for anything that would have caused that. One other possible scenario would be that someone has put a wrong sensor through or damaged the teeth by putting some sort of tool (screwdriver/spanner?) through the slot.

[maccy]

When mine went one of the thrusts was so worn one of them fell into the sump,(the one that is loaded when you put your foot on the clutch pedal) on its way to the sump it mangled the reluctor ring and bent the thrust double.I am not heavy on clutches so I can only assume that it was worn with a heavy clutch user before I had the car.If I can find it I will have a go at putting a picture of it on the forum.I can only assume that when the car went around a corner,centrifugal force pushed the crank over onto the unworn thrust and let the worn one slip out.Any more news Sebseb ?

[maccy]

14 minutes ago, maccy said:

When mine went one of the thrusts was so worn one of them fell into the sump,(the one that is loaded when you put your foot on the clutch pedal) on its way to the sump it mangled the reluctor ring and bent the thrust double.I am not heavy on clutches so I can only assume that it was worn with a heavy clutch user before I had the car.If I can find it I will have a go at putting a picture of it on the forum.I can only assume that when the car went around a corner,centrifugal force pushed the crank over onto the unworn thrust and let the worn one slip out.Any more news Sebseb ?

 

[Sebsebworcester]

On 04/09/2018 at 16:38, maccy said:

I don’t want to be the harbinger of doom,but my old Fabia with a 1.4Tdi engine had exactly the same thing and it took forever to find it.The car eventually stopped totally and had to be recovered.It turned out that the crankshaft thrust washers were so worn,the one nearest to the flywheel fell out and the crank moved away fromthe crank sensor.It had also damaged the reluctor ring.The garage that fixed it took the sump off,straightened the bent reluctor ring and fitted a new set of thrusts and the problem was sorted.It happened twice that the car stopped for no apparent reason and then just started again .You really need to check the end float on the crankshaft ASAP.The first time it happened I hadn’t had the car very long and I always wondered if that is why the car was so cheap to get rid of it.

Car's back now. Garage took the sump off and straitghened the bent teeth on the reluctor wheel. Car was fine for an hour then the fault popped up again ie EML + sparks flashing. In terms of driveability, the car is now 95÷ better, no more vibration at idle and only cuts out every now and then when engine is cold. I was looking to see how much would the reluctor wheel cost and try and get it changed at a cheaper home mechanic but struggling to find it anywhere.Might just have to live with it.

[Breezy_Pete]

Part's only £15 on ebay: https://www.ebay.co.uk/itm/Genuine-Volkswagen-Engine-Speed-Sensor-Ring-045105189A/263836544502?hash=item3d6de22df6:g:V0kAAOSwqj5bWInQ

Part number found here: https://skoda.7zap.com/en/cz/fabia/fab/2004-225/1/105-105010/#2

 

The getting to it to change will be a whole lot of labour though... And you still won't necessarily fix it 'cos we don't know why the teeth got bent in the first place.

[rum4mo]

Anything to gain by checking the crankshaft end float at the front end of the crankshaft, if excessive then maccy’s experience might be similar to that engine?

[Jack125]

On 04/09/2018 at 09:25, Wino said:

It does sound like something is making/breaking a (vital!) circuit with cornering forces. Maybe check that the engine ECU connector(s) are fully latched in place, and check battery clamps for tightness?

When you do find the cause of the misbehaviour, please do let us know what it turned out to be.

Hi wino. I know this is a old post. Wondering if you could help me. I’ve got a 1.4tdi bms. G28 reading no signal. Glow plug light flashing. Car idles at 1200 and won’t rev past 3500. Changes loom as it was abit botched up. Changes g28 sensor. Still nothing. Cheers jack

[Breezy_Pete]

What car is this engine in, Jack?

 

[Jack125]

Ibiza 2008 1.4tdi. Old shape