Engine Speed Sensor (G28) - No Signal

[jonrb 0]

Following on from my previous post towards the end of last year where my engine start problems were traced to a faulty ISV, it seems that I have problems again :(

 

In that post I said:

"What I don't understand is why the car failed to start for so long and then suddenly it starts but shows all the signs of a duff ISV. I hope the ISV isn't masking another problem, like a failing ECU or something."

 

Well, it seems like that could have been a little prophetic. I hopped in the car this morning, jut like I do every day as my Corrado is a daily driver, and it cranked but didn't fire. Same symptons as before - clicking relays but no start. :(

 

I've read the fault codes with VAG-COM and have only one:

VAG-COM Version: Release  311.2-N

Control Module Part Number: 021 906 258 CP 
 Component and/or Version:    MOTOR    2,8L 6-Zyl.
          Software Coding: PMC 1 HS    
           Work Shop Code: ##########
1 Fault Found:
00513 - Engine Speed Sensor (G28)
       03-00 - No Signal

 

Looking at other threads on G28 it would seem that 'no signal' is inconclusive and probably bogus as the ignition was on but the engine not running when I got the code. I did clear it and tried reading the codes whilst cranking and the same error code returned.

 

I haven't been able to investigate the problem further yet, but I'm hoping that we can rule out the ISV as it is virtually brand new.

 

I was really hoping that the Corrado wouldn't let me down again so soon, especially since the TVR is at the garage with a cracked head at the moment. I don't need this. :(

 

Other than going through the steps mentioned in other threads (check for spark and fuel, investigate fuel pump or ignition switch, etc.) can anyone offer any useful suggestions?

 

Cheers

Jon

[Reggit 0]

Vagcom will report a speed sensor error-no signal- if the engine is not running.

If it is faulty you won't have a spark or fuel through the injectors. May be worth taking it out and cleaning it. I had similar problem, cleaning it cured it.

 

There is a speed sensor on ebay right now, auction ends monday morning.

[dr_mat 0]

What about the "immobiliser" tab in VAG-COM?

There should be a read-out of faults, and also a measuring block that says "key authorised to start?".

You have, presumably, tried another key....

[HiAsAKite 0]

Hope you get it sorted Jon,

[jonrb 0]

You have, presumably, tried another key....

Ah, well, that's the thing. The spare keys were mislaid several years ago. I'm not pointing any fingers, but last time I saw them was in my wife's handbag. :wink:

I was particularly annoyed as I'd only just spent out £35 on a new alarm plipper. :(

 

So, unfortunately, that's not an option.

 

I did query the immobiliser with VAG-COM and it reported no faults, but I can do it again tonight to be sure.

[dr_mat 0]

It's more that measuring block that will tell you if the key has been authorised. That's for late VRs at least, where they still have the immobiliser ECU and reader coil near the ignition switch...

[jonrb 0]

Mine is a 1996N, so will have the reader coil. I was aware of this problem, but to be honest I hadn't considered it as a suspect as I assumed that if the key wasn't authorised it wouldn't even crank.

I'll investigate further with VAG-COM tonight as suggested.

[dr_mat 0]

The starter circuit is controlled by the ignition key. If the ECU is immobilised, the starter will still crank, but there will be no fuel and no spark. Some alarm fitters tap into this circuit as an additional immobilising line though.

Very new cars switch the starter motor through the ECU (via a chunky relay), but nothing as old as the Corrado does that. (Hell the Corrado doesn't even use relays for the headlights, where it really should!)

[jonrb 0]

(Hell the Corrado doesn't even use relays for the headlights, where it really should!)

Tell me about it. I had a to replace the headlamp switch last year and it was £46 because it has to handle the entire electrical load of the headlamps. Also explains why the switch becomes so hot when the lights are in use.

[jonrb 0]

Yep, key is authorised.

 

I connected to controller 25 (ie. the immobiliser) with VAG-COM and read group 001.

 

I got:

Authorised Start? 1

ECU Answers? 1

Key Condition OK? 1

No. of matched keys: N/A

 

Also, there are no faults recorded for this controller.

 

So that's that theory out of the window. :(

 

I still have a duff front left ABS sensor, by the way, which I must fix before the MOT in 2 weeks time because it will fail on that. I'm assuming that this isn't a problem because it's been like that for about 6 months.

[dr_mat 0]

Looks like you're gonna have to bite the bullet and take a look if there's a spark..

Might be worth pulling/reseating some of the ECU relays too.

[Ady_G 0]

jonrb, you may have seen this thread from a couple of weeks ago

 

http://the-corrado.net/.archive/forum/viewtopic.php?t=21449

 

I thought my VR6 had a engine speed sensor failure, then immobiliser problems, but it was the ignition switch in the end.

 

Might be worth checking because they are only £15 (ish), compared to more expensive sensors.

 

Hope you get it working.

 

Ady

[jonrb 0]

Looks like you're gonna have to bite the bullet and take a look if there's a spark.

Indeed. I was thinking the same thing. Unfortunately my wife didn't fancy coming out into the dark and turning the key for me. :roll: :(

I'll talk nicely to her tomorrow and get her to do it in daylight (which isn't so good for me trying to see a spark, but there you go).

 

Hope you get it working.

Thanks for that Ady.

[jonrb 0]

I got one of the plugs out using the spark plug tool in my trusty Halfrauds socket set. I managed to remove the near left-most (looking at the engine from the front of the car). Couldn't remove the left rear-most - I guess I need the infamous extra-long spark plug removal tool that Webbo sourced a while back.

 

Anyway, I pulled out the plug lead, removed the plug, connected the plug back onto the lead and then got the missus to come out and crank it over.

 

No spark. Not a glimmer even in pitch dark.

 

So I guess it's not the fuel pump then. :)

[chargedupstorm 0]

Hi JRB,

 

As mentioned above, you need to check that it’s not the factory immobiliser in VAG-COM or 1552, if not do the following:

 

To rule out the immobiliser problem, I'd recommend getting another key cut (non transponder).

Drop the lower plastic steering cowling, and with the new key in the barrel try and start the car, if you are getting the same symptoms then it could be the transponder reader on the ignition column.

If you hold your original key close to the reader, (a cylindrical object with a wire leading from it around the steering column) and try and start the car again.. see what happens, many many moons ago I had a problem with my VR6 where the coil had slipped down the column and intermittently worked. Another problem had been the contacts on the transponder reader itself, it’s work disconnecting this and spraying some WD40.

 

Good luck,

Guy

[jonrb 0]

Hi Guy - long time no 'see'. Hope you're well.

 

I've queried the Immobiliser module with VAG-COM and the key is authorised (see earlier post). Is that sufficient to rule this issue out?

 

Cheers

Jon

[jonrb 0]

My dad lent me a spark tester over the weekend. It's a sort of pair of plastic dividers with a metal nipple like a spark plug on one side and a point on the other. You connect one side to the lead and touch the other on the block and the spark jumps across the gap and you can increase the gap to find out how good the spark is.

 

Great. Just what I need.

 

Pity that the shrouds of the HT lead sockets on the VR6 are so long / deep that I can't plug this tester in to a lead. :(

 

So I popped into my local auto factors and picked up one of these:

 

(It's a Draper Ignition Tester. Cost under a fiver)

 

I'll give it a go tonight and then I'll know if we have spark or not. That's assuming the shroud on the lead isn't too long for this too.

[jonrb 0]

Well, the probe was long enough. It was a bugger to get the socket onto the spark plug though as it is so recessed. I had to Gaffer tape a small tent peg to it in the end, and then it was easy.

 

When I turn the key into the ignition position, the bulb glows very briefly. When I then turn over the engine I get nothing - not a glimmer.

 

I was going to test the tester in a "known good" situation by trying it on one of my other cars, but they have even more inaccessible spark plugs than the Corrado!

However, I think the fact the bulb glowed briefly means the bulb works (and it wasn't it blowing because I tried it several times) so I'll make the assumption that the tester is ok.

 

So, does that give anyone anything more to go on?

 

All help appreciated - I've reached the end of my own knowledge.

[Reggit 0]

If I was you I'd take a spark plug out and lie it on the engine to test it (connected to the HT lead of course!).

 

I found that if you take the plug out at the front drivers side of the engine you can turn the engine over and watch the plug at the same time if you open the drivers window and reach in to the key.

 

With the plug out, check if you can smell petrol after cranking it for a few seconds. If you can't and have no spark it is pointing to the speed sensor.

 

Mine had the exact symptoms as yours and no faults on vagcom. I found that removing sensor, cleaning and replacing cured the problem. It is roughly central at the bottom front of the engine, held by a 5mm allen bolt. If you can jack the car up and put an axel stand under to support it, you should be able to have it out in 5 minutes.

[jonrb 0]

Mine had the exact symptoms as yours and no faults on vagcom. I found that removing sensor, cleaning and replacing cured the problem. It is roughly central at the bottom front of the engine, held by a 5mm allen bolt. If you can jack the car up and put an axel stand under to support it, you should be able to have it out in 5 minutes.

Thats encouraging. And if it as easy as that then I may clean it on spec. I have a trolley jack and axle stands, although the car is lying on a gravel / peddle drive at the moment which always worries me with jacking.

 

How would one clean the sensor? Electrical switch cleaner? WD-40? Carb cleaner?

 

Does anyone have a picture of it so I take off the correct thing?

[Reggit 0]

Just taken this piccy from under car, sorry it's a bit out of focus.

 

You'll find it is just a sealed metal can, I wiped mine clean with a cloth.

[jonrb 0]

Thanks for that. I'll get the car up on the trolley jack and axle stands on the weekend and have a go.

[jonrb 0]

Well, I've had the car up on the trolley jack and axle stands. I hope I chose the right jacking points - I chose the rearmost part of the lower wishbones where they bolt to the car.

 

The 5mm allen bolt was seized solid and WD-40 didn't shift it. However 3-in-1 Pentrating Oil Spray (ooer) and a suitable extension to the allen key for leverage did the trick.

 

As soon as I got the sensor off I knew that cleaning it wasn't going to fix it; it looked brand new with just a tiny bit of oil on it. I cleaned it anyway and reassembled and sure enough the car still failed to start afterwards. :(

 

I decided to test for spark the traditional way whilst I was at it - spark plug out and on the HT lead and held near or against the block. No spark.

I had a sniff for petrol but couldn't smell any so I may or may not have fuel. Inconclusive on that, but conclusive on lack of spark.

 

I think I'm going to have to get it recovered to a local garage to be fixed. I know there's a guy in Fleet who does Alfas and VWs, and I know that White's service centre is in Aldershot . I've also heard there's someone in Farnborough who mainly air-cooled VWs but does others too.

The only trouble is that I have an MOT due on Tuesday (05/04/05) and I have a failed N/S/F ABS sensor (which would be an MOT failure) so I'd need someone to do it all.

 

My RAC cover will take the car to any garage within a 10 mile radius, so covers all of the above. I'd best start doing some research. :(

[vr6storm 0]

The only trouble is that I have an MOT due on Tuesday (05/04/05) and I have a failed N/S/F ABS sensor (which would be an MOT failure) so I'd need someone to do it all.

 

My RAC cover will take the car to any garage within a 10 mile radius, so covers all of the above. I'd best start doing some research. :(

 

 

well to save you a phone call to yer local $tealer......the front ABS sensors are approx £41+VATage and you need to tell them what side it is as they are "handed".........i would imagine they should have them in stock too

[jonrb 0]

phone call to yer local $tealer......the front ABS sensors are approx £41+VAT

£24.80 + VAT at ECP and £21.50 +VAT at GSF. ;)