So fuse 4 engine side keep is blowing…

 

It’s appears to control:

 

Radiator fan,

 

control valve for fuel
pressure,

 

relay for electric auxiliary
heater
 

Bit when it blows, it’s takes out the oil temp sensor (oil sensor: workshop! On dash) And the turbo…… so it must controls more, but I can’t find what else!

 

As I said on another thread (this one is more fuse 4 function specific), a guy cleaned a sensor under the engine whcih I though was interfering, and it worked fine for 500 miles.

 

My heater is slow, and only blowing cold out of drivers side. I understand this many be due to the silica bag dropping into the matrix, which is in front of the auxiliary heater right?

 

Can this be connected?

 

Ive seen your post of facebook about this too, im gonna ping you over a wiring diagram shortly and help you get to the bottom of it once and for all. 

Where are you based?

 

@sapf0 do you know your engine code? 2.0 TDI i assume?

Edited 2 January, 20224 yr by ApertureS

A wire (intermittently) shorting on some engine metalwork is my guess.

8 minutes ago, ApertureS said:

Ive seen your post of facebook about this too, im gonna ping you over a wiring diagram shortly and help you get to the bottom of it once and for all. 

Where are you based?

 

Birmingham mate. Thanks 

6 minutes ago, Wino said:

A wire (intermittently) shorting on some engine metalwork is my guess.

 

I forgot to mention. The last 3 times I’ve done trial & error runs, it’s popped hooking a right turn at the same place. 
 

I did recently have the DSG service done a Central VW & Audi, and they’ve got to have had my battery tray & airbox out I guess. 

Okay so ive done some research for you and this is what were working with 

 

Fuse SB4 is a 7.5A fuse which is a black with red trace wire it then goes through the multiplugs to the engine in either 3 or 4 places depending if you have adblue.

 

It supplies 12V to 4/5 components and those are

 

Adblue relay J963 - Only applicable if you have adblue

Coolant control valve N489

Oil Control valve N428

Boost Control valve N75

Oil level sensor G266

 

 

So out of possible causes there are 2 faults you could be looking at:

- A failed one of these components causing a dead short and blowing the fuse

- A failed wire/insulation shorting out causing a dead short and blowing the fuse

 

To find the fault first were gonna need to know, how often is it blowing the fuse, is it instantly or not?

 

 

 

 

 

A few more details for you of locations

N489 - on top of the water pump and controls the shroud- red plug

N428 - oil control valve is behind the AC compressor on the front of the block

N75 - on the bulkhead behind the turbo intake pipe with a few rubber hoses going into it

G266 - in the bottom of the sump

 

 

You have 3 components there in some kind of fluid and 1 with a large coil that was known to fail.

I would first be disconnecting the N489, N428 and G266 and checking for oil/coolant in the plug causing a short.

If you have a multimeter you can check the resistance of the N75, N428 and N489 valves to see if they are short circuit, connect your multimeter and tap the components to see if the resistance changes much

 

If you want to find the fault yourself you will need a multimeter or if you make a test lamp at home with a 382/501 bulb I could also teach you this method.

 

Edited 2 January, 20224 yr by ApertureS

41 minutes ago, ApertureS said:

Okay so ive done some research for you and this is what were working with 

 

Fuse SB4 is a 7.5A fuse which is a black with red trace wire it then goes through the multiplugs to the engine in either 3 or 4 places depending if you have adblue.

 

It supplies 12V to 4/5 components and those are

 

Adblue relay J963 - Only applicable if you have adblue

Coolant control valve N489

Oil Control valve N428

Boost Control valve N75

Oil level sensor G266

 

 

So out of possible causes there are 2 faults you could be looking at:

- A failed one of these components causing a dead short and blowing the fuse

- A failed wire/insulation shorting out causing a dead short and blowing the fuse

 

To find the fault first were gonna need to know, how often is it blowing the fuse, is it instantly or not?

 

 

 

 

 

A few more details for you of locations

N489 - on top of the water pump and controls the shroud- red plug

N428 - oil control valve is behind the AC compressor on the front of the block

N75 - on the bulkhead behind the turbo intake pipe with a few rubber hoses going into it

G266 - in the bottom of the sump

 

 

You have 3 components there in some kind of fluid and 1 with a large coil that was known to fail.

I would first be disconnecting the N489, N428 and G266 and checking for oil/coolant in the plug causing a short.

If you have a multimeter you can check the resistance of the N75, N428 and N489 valves to see if they are short circuit, connect your multimeter and tap the components to see if the resistance changes much

 

If you want to find the fault yourself you will need a multimeter or if you make a test lamp at home with a 382/501 bulb I could also teach you this method.

 

 

It’s a 10a fitted in fuse 4. (Engine bay)

 

No AdBlue 

 

I have a multi metre 

 

 

1 time it went I changed the fuse and it blew 30 Mins later 

 

2nd time a local auto elec guy cleaned a lower sensor (pic), and it was fine for 500 miles.

 

Now I have replaced it multiple times, unplugging a few components underneath, like that sensor in the picture, the oil level sensor, & the fan, to try to eliminate, but it blows either on pull off, not idle, or when I get a mile down the road and take the same right turn weirdly enough.

9 minutes ago, sapf0 said:

 

It’s a 10a fitted in fuse 4. (Engine bay)

 

No AdBlue 

 

I have a multi metre 

 

 

1 time it went I changed the fuse and it blew 30 Mins later 

 

2nd time a local auto elec guy cleaned a lower sensor (pic), and it was fine for 500 miles.

 

Now I have replaced it multiple times, unplugging a few components underneath, like that sensor in the picture, the oil level sensor, & the fan, to try to eliminate, but it blows either on pull off, not idle, or when I get a mile down the road and take the same right turn weirdly enough.

What youve unplugged is an auxilary water pump and that is not on this same circuit. You need to be looking at the 4 sensors i have listed above (ignore adblue then). 

I would unplug the sensors 1 by one and see what happens, you will get other faults in doing so

Coolant solenoid - car will begin to overheat if driven really hard/fast over temp so dont go too far

Oil control - should default to a safe position but make sure you dont get an oil no pressure warning

N75 boost valve - you will get a lack of power when unplugged

oil level sensor - you may get a eml/level sensor fault.

 

Try each of these and when you unplug them also check the plug for oil as there should be any inside.

 

Also your engine is leaking a lot of oil! probably rocker cover gasket.

 

 

EDIT: In the petrol engines its a 10A fuse, in the 1.6 and 2.0 TDI it is a 7.5A fuse.

Edited 2 January, 20224 yr by ApertureS

Whilst unplugging and inspecting connectors, also look at the loom sections that go to each, hunting for possible wire abrasions on metalwork that they pass.

I use a switch cleaner when I break and remake plug connections, it is strange how many problems it helps disappear 😀

Edited 2 January, 20224 yr by gumdrop

1 hour ago, ApertureS said:

What youve unplugged is an auxilary water pump and that is not on this same circuit. You need to be looking at the 4 sensors i have listed above (ignore adblue then). 

I would unplug the sensors 1 by one and see what happens, you will get other faults in doing so

Coolant solenoid - car will begin to overheat if driven really hard/fast over temp so dont go too far

Oil control - should default to a safe position but make sure you dont get an oil no pressure warning

N75 boost valve - you will get a lack of power when unplugged

oil level sensor - you may get a eml/level sensor fault.

 

Try each of these and when you unplug them also check the plug for oil as there should be any inside.

 

Also your engine is leaking a lot of oil! probably rocker cover gasket.

 

 

EDIT: In the petrol engines its a 10A fuse, in the 1.6 and 2.0 TDI it is a 7.5A fuse.

 

Is a 10a causing any issue itself then? It was a 10a that was taken out, which if it is supposed to be a 7.5a, then it’s clearly been replaced previously.

10 minutes ago, sapf0 said:

 

Is a 10a causing any issue itself then? It was a 10a that was taken out, which if it is supposed to be a 7.5a, then it’s clearly been replaced previously.

a 10A in itself wont be causing the issues no but the fact it was already 10A says its been replaced previously yes. Start with them bits ive suggested then come back to me. There are alternatives to keep blowing fuses during testing such as creating a 382 test lamp and putting that in the circuit or using a resetable fuse

This started happening today intermittently. Only on the right speakers. Last night I heard a clicking sound going through the speakers from front to back. 
 

It was the same on other stations.

 

https://youtube.com/shorts/UgZF0978Qow?feature=share

On 02/01/2022 at 22:09, ApertureS said:

a 10A in itself wont be causing the issues no but the fact it was already 10A says its been replaced previously yes. Start with them bits ive suggested then come back to me. There are alternatives to keep blowing fuses during testing such as creating a 382 test lamp and putting that in the circuit or using a resetable fuse

 

Took it to a local auto elec garage. He spotted this. This could be the result of a recent gearbox engine (dogbone) mount bush failure which caused engine movement for a few days before being fixed.

 

see his note re: fuse 4 wire

He said there was not rusting so appears recent, which fits in with that failed mount.

 

How can that relate to fuse 4?

So the red/back is the feed to all the components, once it goes through the components it comes out as all the different trigger wires back to the ECU. If one of these wires is the trigger wires it is still shorting out, just via a component. Ill check the diagram again for you and see what they are (if theyre on the F4 circuit)

 

The trigger wires on this circuit are the following colours: (there could be more than 1 of a colour by the way)

Brown & Yellow

Blue & Violet

Grey & Violet

A brown wire

Grey & Yellow

 

That picture also looks more like something has rubbed through than stretched, gonna need to look a bit more in depth and before checking the loom the components need checking as i described. 

Edited 6 January, 20224 yr by ApertureS

So a few weeks later, and that Repairs seems to have solved that problem and fuse 4 engine bay no longer blows.

 

I now have a new problem, which I will post in a new thread. 😂 

 

Thank you for all of your help.

On 20/01/2022 at 11:04, sapf0 said:

So a few weeks later, and that Repairs seems to have solved that problem and fuse 4 engine bay no longer blows.

 

I now have a new problem, which I will post in a new thread. 😂 

 

Thank you for all of your help.

What was the fault in the end that caused this issue?

On 21/01/2022 at 13:11, ApertureS said:

What was the fault in the end that caused this issue?

It appears that it was those wires that were causing fuse 4 engine side to blow. I have had the turbo code pop up again and it goes into limp mode. But a reset solves that problem, and it’s maybe once per week (1000miles).