injection system control unit

D

davidmac

Member
Can anyone tell me where to find the Diesel direct injection system control unit.I have "no 3 injector with intermittent fault" and also G62 Coolant temperature sender "power short to earth".The gauge reads perfect by the way and operates as expected:confused:The latter fault ties into pins 104 and 112 on the injection system control unit which could have a bearing on no' 3 injector which ties into the same control unit on pins 121 and 114.Can a power short to deck pull 1 injector down.Or are both faults unrelated.Not sure if voltages are digital / analogue or possibly both.Skipton or Spike this might be more up you guys street:)
Cheers Davy
 
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Hi Davy
The engine control unit (ECU) is located in the passenger footwell.
A couple of club members have reported faults with the injector wiring harness so that may be a good starting point for the injector problem.
I would guess the coolant temp sender problem is not related. Failure of the G62 sensor is quite common on many Audi models so this may be the first indication of imminent problems. Ususal signs are the temp gauge needle starts to wander, showing the normal 90deg reading then suddenly dropping and recovering again.
If you have not already done so, check your fault codes on the RossTech webe site as they often give helpful troubleshooting tips
http://wiki.ross-tech.com/index.php/Category:Fault_Codes

Cheers Spike
 
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Hi Davy,

I'm pretty sure that the faults are unrelated tbh. The diesel direct injection controller is better known as the engine ECU and it lives under the passenger footwell compartment - the silver box with 2 large multi-pin connectors.

The G62 temperature sensor is prone to failure and has been redesigned, so that ones you buy now are the new, more reliable versions. It is located on the left hand side of the cylinder head on your TDi and is connected via a 4-wire/4-pin black connector, as it also contains the G2 coolant sensor.

Cheers,

Mike
 
Thanks for the input skipton/spike.Didn't see any way the 2 could be related other than through a shared earth possibly going momentarily live through the G62.I will try ross tech Spike and see what turns up.
Cheers Davy:)


Checked fault codes 17664: G62 sensor no probs but what is this mince.

18076 : Wiring and/or connections to/from the Valve for Pump Jet
Valve for Pump Jet

Wiring/connections no probs . Valve for Pump Jet ??????????????? .Does pump jet mean injector and the valve being some sort of flow control to the injector.If so where does this little !!@* live.
Cheers Davy
 
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Hi Davy
The PD injectors incorporate a solenoid valve on the side of the injector body - which controls the fuel delivery as you thought. Access to these solenoid valves requires removal of the rocker cover
Maybe PD is short for 'pump jet' in German

Cheers Spike
 
Coincidentally my TDi A2 has been found to have the same Temp sensor problem, as well as being told it needs new injectors. The injector problem was diagnosed after all the brake warning lights (main red ssytem failure, abs, and edf lights together)

Any thoughts?
 
I believe that the 'dual' temp sensor G62 has two outputs one for the gauge in the clocks and the other to the ECU. Often the one connected to the clocks side fails, but in your case Davy, looks like its the other way around.

If you have Vag Com you can read the temperature this way and if it fails to read correctly then this proves that the sensor IS faulty, even though it shows correctly on your dash. There could be consequences to this as the ecu will be making calculations with the given 'wrong' information from the sensor, for example it might be running a little rich (more fuel consumption) as ecu thinks engine is cold, Also may affect other settings/ parameters too.

Just thinking out aloud here. :eek:


Cheers

Sarge
 
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rontheman said:
Coincidentally my TDi A2 has been found to have the same Temp sensor problem, as well as being told it needs new injectors. The injector problem was diagnosed after all the brake warning lights (main red ssytem failure, abs, and edf lights together)

Any thoughts?
Click to expand...

Hi rontheman, welcome to the A2oc.
Injector problems are extremely rare so I would suggest a second opinion before splashing out hundreds of pounds on new injectors. If the engine occasionally misfires then it could be the injector wiring harness to blame.

Cheers Spike
 
I'd second Spikes comments on the injector harness. Can be quite random to start with and it will slowly get worse to where it starts missing everytime you run the car.

I replaced mine its around £40 from memory. Remove cam cover (which first of all means taking air inlet to cabin out of the way) and you will see it at the front. Fairly easy to change from that point on. Ive done over 10,000 miles now since the change with no further issues. If you search theres a post where i listed all the fault codes, I cant remember exactly but its very similar description to what you posted.

Gary
 
Coolant temp sensor.

The coolant temp sensor i a well known weak part. I have changed mine two times in one year. Cost about 30 quid. And, although a relatively cheap and small part, you would be amazed how it will mess with your car if it is faulty.

-P-
 
Thanks Spike and Gary.

Any thoughts why all the brake warning lights should come on every time the engine starts running rough (ie the "injector" problem). Is there some cross connection within the ECU? I have obviously had the brakes checked at a dealer and they said the only problems showing up on diagnostics were the coolant temperature sensor and one fuel injector. The car was serviced some 3 weeks ago and, presumably, nothing showed up on the diagnostics (or else I would have been told)
 
With the injector problem the dash will light up like a xmas tree! from memory you get at least the ESP light a big warning triangle in the centre display, ABS, and probably the engine light too!, and it will emit a warning beep.

im not sure of the reasons for all the lights coming on, but it encourages you not to carry on driving I suppose. If you have had any code relating to injectors particularly intermittent faults with the solenoid valve (probaby wiring to/from), i would definately replace the injector loom before resorting to anything much more costly.

Have a read of this thread for my history on this subject.

http://www.a2oc.net/forum/showthread.php?t=8289&highlight=injector+harness

Hope its of help.

Gary
 
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Many thanks for your prompt response to this. My dealer wants to charge me £1700 for 3 new injectors. I am going into the dealership tomorrow (my A4 needs a service) and will bring up the various points made here for their feedback, and some indication of the error codes.

I will post the feedback here tomorrow, if you wish

Ron
 
Hi Ron
Main dealers are not very receptive to diagnostic solutions from car club 'experts' so be very diplomatic in your discussions.
If it really is an injector problem, PD injectors can be tested and rebuilt - http://www.feather-diesel.co.uk/contents09/technical/technical_detail.php?1
so if you could afford to be without the car for a while this may be a cheaper option. I guess Audi would not be interested in going down this route so you would need to find an independent garage to do the work

Cheers Spike
 
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Sarge786 said:
I believe that the 'dual' temp sensor G62 has two outputs one for the gauge in the clocks and the other to the ECU. Often the one connected to the clocks side fails, but in your case Davy, looks like its the other way around.

If you have Vag Com you can read the temperature this way and if it fails to read correctly then this proves that the sensor IS faulty, even though it shows correctly on your dash. There could be consequences to this as the ecu will be making calculations with the given 'wrong' information from the sensor, for example it might be running a little rich (more fuel consumption) as ecu thinks engine is cold, Also may affect other settings/ parameters too.

Just thinking out aloud here. :eek:


Cheers

Sarge
Click to expand...

Hi Sarge hows your dad,Good I hope.
This is an old post of mine from May last year.My symptoms were very definate and after changing the harness within the rocker cover were no more.Never bothered with the temp sensor as all seemed to be ok.Plenty food for thought though with regards to wrong info being sent to the ECU.Cheers Davy
 
Hi Davy, Dad is ok thanks, he is returning on Sunday then I shall really know. Me however just had a throat and stomach operation yesterday and despite suffering bouts of unconsiousness, & unable to see in focus, I still can't stay away from this site. As I Can't talk though, wife's probably never been happier ..lol still got the sense of humour, even after surgery ;)


Cheers

Sarge
 
rontheman said:
Many thanks for your prompt response to this. My dealer wants to charge me £1700 for 3 new injectors. I am going into the dealership tomorrow (my A4 needs a service) and will bring up the various points made here for their feedback, and some indication of the error codes.

I will post the feedback here tomorrow, if you wish

Ron
Click to expand...

Hi Ron, how did you get on.
I just wondered if they thought any of the comments and suggestions made by club members were worth further investigation.
Hope I was wrong in pre-judging their attitude.

Cheers Spike
 
Sarge786 said:
Hi Davy, Dad is ok thanks, he is returning on Sunday then I shall really know. Me however just had a throat and stomach operation yesterday and despite suffering bouts of unconsiousness, & unable to see in focus, I still can't stay away from this site. As I Can't talk though, wife's probably never been happier ..lol still got the sense of humour, even after surgery ;)


Cheers

Sarge
Click to expand...

Hi Sarge the wife will want you about the house to make the most of the peace an quiet :D Its good dads ok and hope you make a good recovery as well take care
Davy
 
Many thanks to all

Hi Spike

Sorry for the delay in getting back, but only now has the problem been resolved. Basically you were right!! It was the harness (£130 installed, compared with £1,700 for new injectors).

After the dealership told me the car needed injectors, I had a long chat with the senior engineer there and showed him the comments on here. The car went in last week for a further look. The dealership installed the new harness and hey presto, no problem. They road tested it over 2 days, and since getting the car back, it runs fine.

So again, you were right, they were wrong. Thanks to everyone for their input, especially you Spike!

Ron
 
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