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T5 AXD - G62 16502 - SOLUTION!

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liamo333 View Drop Down
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    Posted: 14 Oct 19 at 19:26
Hello all,

So I've been plagued with this fault for a little while now and it seems that many others have too.
Managed to sort it today, thought I'd share a bit as I've gotten loads of info off here and only fair to give back a bit (and of course to gloat :p).

Here were my symptoms:

Fault code 16502

Van started like a pig, it would turn over and fire after a few seconds. Then hover at around 500rpm and die. It would normally start second time. Where I live it gets down to below 15c, once its that cold it may not start it all.

No torque, stalling all the time and I'd have to rev like fuck to get out of the drive.

Fan on all the time. 

Heres what I did:

Tools first though : decent set of small sockets up to 13mm and different torx drivers. With a small 1/4" ratchet to get into small spaces. Plus a couple monkey grips and other basic hand tools. Multimeter and a code reader. 

Bumper off, plenty of info on this its its not a big deal. If yours is anything like mine it'll be held on with cable ties and self tappers. I used a ratchet spanner for the nuts in the arches, this could be a balls without the right tools.

Lights can stay where they are but take off the coolant expansion tank and the washer liquid thing, gives you some space to work. 

Keep the battery connected for the minute.

Now I was told about taking off the sub frame and a few other things but heres what i did to get access to the manifold area behind the radiator:
Theres a couple bolts in the top of the rad holding it in. Take them off and push the bit they're screwed into down. Take off the coolant pipe to the rad on the RHS, i stuffed a couple of rags into each end to stop it from leaking too much but you'll want a tray below all the same. Theres a small pipe on the rad LHS too, take this off, shouldn't be any coolant inside. 
Take off pipes either side of the intercooler, the big fat ones. 
There was a smaller rad for the steering fluid I think here too, this can be clipped off and hang more or less free, then when next step is done cable tie it out of the way.

Now I was able to lift up the rad and wiggle it out the front with the bottom coolant hose still attached. I left it leaning down and that gave me plenty of space to work. 

The coolant temp sensor is under the manifold deep in the back RHS (van's RHS not yours). Should be able to spot it now. 

Before going to the effort of changing it I checked it with a multimeter, the new and old one were both reading 1700ohms. It was fine, no need to change. Next turn on ignition but don't start the van. Check the plug going to the sensor, should be 5v. 

If you are doing this and you've got the 1700ohms and 5 volts then fuck knows whats wrong with it, I cant help you any more :p 

I had zero volts. I followed the cable to try and find a break but theres too much shit in there to get it out cleanly. Its a blue and brown wire coiled together.

Stage 2: Remove the battery and take out the two plates to get into the brains of the van. Theres a little metal bracket securing the ECU connections, take this off. Think you need a T20. Then take off the plug on the LHS of ECU (again, the ECU's LHS, not your's). Your blue and brown wires should be in here. Now I couldn't for the life of me get my multimeter probes anywhere near some copper to test the cables, Stanley knife sorted this out though, just open them at little at different lengths so if your dodgy electrical tape jog goes wrong they wont be contacting each other. 

Helpful to have a friend for this one. Check for continuity/resistance from your cable at the ECU back to your corresponding cable at the plug. I had nothing, on either the + or - . I snipped the cable at a reasonable distance from the ECU to make a decent connection. Same on the temp sens side. I guess you can see where this is going... Now I think its easier to just make a new cable than ordering one, i imagine its a pain to change those connections in the ECU block. If you do make a new cable then be sure to do a very professional job like myself and use 1.5mm2 single core lighting cable :p Cant drive to the shops when your vans in bits! 

Anyway! New cable, get the battery back in and check your code reader. Hopefully everything ok. 

If your G62 sensor is buggerd and you want to change it then it seems like you're going to need some longer extensions and probably a very long needle nose pliers and some patience. Doesn't look too bad but would be worth draining all the coolant because theres no way you'll get the other one in quickly. 

Anyway there you go, hopefully this helps someone out. I haven't seen too many success stories on the subject. I guess its all about checking the sensor and checking the cables, all another piece of the troubleshooting process. 

Its not all that tricky really, easier to get the front off than expected cant go too far wrong. 

HOW DO I POST PICTURES???

Peace




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Vanorak
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Post Options Post Options   Thanks (0) Thanks(0)   Quote T5 TDI Quote  Post ReplyReply Direct Link To This Post Posted: 14 Oct 19 at 20:28
Edited-  Explained below.

Edited by T5 TDI - 15 Oct 19 at 10:11
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gregozedobe View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gregozedobe Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 19 at 01:27
Thank you !  I'm sure that info will help someone.  Thumbs Up
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liamo333 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote liamo333 Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 19 at 08:11
Heres some images, not sure how helpful they are but they'll give a good idea of what needs to be done. 

Just one thing to say, dont bother going near the sensor if you dont have a multimeter and a code reader. They can both be bought for less than 20 euro. If you're going to go to the trouble of taking the front of the van off, removing your sensor, reinstalling it and putting the van back together to see if it changes and actually the problem was wiring or something else. Thats a lot of work when if like me your sensor is ok and theres a wiring problem. 

Front of the van off, and rad tilted forward no need to take the subframe off. 


Little red circle is on the part or the radiator that needs to be pushed down to wiggle it out.


Red arrows pointing to G62 sensor location and plug, if you've got this far you wont need this picture but there you go anyway.


This is under the battery, theres two plates to take off. The blue and brown wires are in the plug on the right hand side, they're easy to find. 

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Post Options Post Options   Thanks (0) Thanks(0)   Quote T5 TDI Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 19 at 09:59
I've now added your link so it appears within the list of how-to-do's. Thumbs Up

When I replaced the G62 (see eleswere on the list) on mine I took the bumper off, disconnected the intercooler pipe and slid the whole panel back on a couple of home made pins.  I didn't disconnect the radiator or remove the subframe.

It's a good point about testing the G62 first.  I was going to change my G62 anyway because they aren't reliable and I reckoned I would have to take the front off anyway.  Thinking about it, perhaps the pigtail extension loom on the G62 would have made it just possible to test it with the front still in place but it would be very tight to get the multiplug disconnected. 

Good stuff!  Smile 

  

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liamo333 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote liamo333 Quote  Post ReplyReply Direct Link To This Post Posted: 15 Oct 19 at 11:54
Yeah I opened it all up with the intention of changing it myself but then figured i may as well check the resistance at the same time. It was the same as the new one so i figured I'd keep looking for something else. Not sure how it works with the pins but I think I know what you mean. 

Was told I'd have to take the subframe off which I wasn't keen on! Glad it was a relatively simple fix and I didn't take it to a French garage!
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