sensors
05-01-2011, 09:54 AM
#1
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sensors
2004 Allroad 2.7 with 6spM
MY CEL started coming on intermittently a month or two ago and a scan at that time using a buddy's diagnostic cable showed a low temperature warning.
The car was running fine so I've been putting off getting that sorted but in the meantime the car was in for a clutch and the shop told me they also saw an exhaust gas temperature warning, which did not come back after they cleared it.
As of today, the car is still running fine, but the CEL is on steady and a looming smog test means I should replace some sensors. I haven't scanned the codes recently so I don't know if the EGT is bad for sure, I need to visit my buddy to do that. In the meantime I'm doing my research.
1) The coolant temp sensor: The drawings I have suggest that there is a single coolant temperature sensor at the top-rear of the engine. Sat next to it is similar device which the drawing says is a switch. At the bottom front of the engine, actually in the hose leading to the radiator, I visually identified what I thought was a temperature sensor, but the drawing says this is also a switch.
So the questions are:
a) Is there only one temp sensor?
b) Should I also replace the switches?
2) Exhaust gas temp sensors: I have been told where they are and looking at the top of the left side turbocharger I can see one two attachments, one of which must be the left side sensor. I don't have any drawings. I also couldn't find these sensors on-line at AudiUSAParts.com
Questions here are:
a) Is AudiUSAParts.com a preferred source?
b) What is (are) the part number(s) for the EGT sensors?
c) Does anyone have a drawing or a link to a drawing that will let me fing the EGT sensors easily.
Many thanks.
jasper
MY CEL started coming on intermittently a month or two ago and a scan at that time using a buddy's diagnostic cable showed a low temperature warning.
The car was running fine so I've been putting off getting that sorted but in the meantime the car was in for a clutch and the shop told me they also saw an exhaust gas temperature warning, which did not come back after they cleared it.
As of today, the car is still running fine, but the CEL is on steady and a looming smog test means I should replace some sensors. I haven't scanned the codes recently so I don't know if the EGT is bad for sure, I need to visit my buddy to do that. In the meantime I'm doing my research.
1) The coolant temp sensor: The drawings I have suggest that there is a single coolant temperature sensor at the top-rear of the engine. Sat next to it is similar device which the drawing says is a switch. At the bottom front of the engine, actually in the hose leading to the radiator, I visually identified what I thought was a temperature sensor, but the drawing says this is also a switch.
So the questions are:
a) Is there only one temp sensor?
b) Should I also replace the switches?
2) Exhaust gas temp sensors: I have been told where they are and looking at the top of the left side turbocharger I can see one two attachments, one of which must be the left side sensor. I don't have any drawings. I also couldn't find these sensors on-line at AudiUSAParts.com
Questions here are:
a) Is AudiUSAParts.com a preferred source?
b) What is (are) the part number(s) for the EGT sensors?
c) Does anyone have a drawing or a link to a drawing that will let me fing the EGT sensors easily.
Many thanks.
jasper
05-01-2011, 09:58 AM
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Haha - I just looked at the drawings again and I see there is a second temp sensor...part 35 so I think I've answered my own first question...
As for the second...Given that my error is *low* temperature I am thinking the switches aren't failing, unless they have falied open of course.
As for the second...Given that my error is *low* temperature I am thinking the switches aren't failing, unless they have falied open of course.
05-01-2011, 10:19 AM
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I found this article on the EGT sensor swap...seems appropriate:
https://www.audiworld.com/tech/eng73.shtml
I guess I could have searched a bit harder before I posted
Still any wisdon is appreciated!
https://www.audiworld.com/tech/eng73.shtml
I guess I could have searched a bit harder before I posted
Still any wisdon is appreciated!
05-01-2011, 02:41 PM
#4
AudiWorld Senior Member
Frequently temperature sensors are 'the root of all evil". 
They are at least the first place to start. They're not too expensive and often cure all of your ills.
However, if that doesn't work, EGT sensors are expensive. Let's hope for the best.
They are at least the first place to start. They're not too expensive and often cure all of your ills.However, if that doesn't work, EGT sensors are expensive. Let's hope for the best.
05-02-2011, 06:24 PM
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It is m0st likely (3) which is ECU em sensor. 3A is after run pump switch and the one up front is your gauge temp display sensor...
Your (3) is probably shot (very common) and never shows higher than whatever it is stuck at temperature triggering ECU error once the ECU figures out that the temp should already be higher than what sensor shows. Unfortunately driving with this sensor shot has another side effect which is bad MPG since ECU is constantly running on warm up fueling which dumps additional fuel...
Fix it asap, it is very easy to swap and hopefully it fixes all of your issues.
Your (3) is probably shot (very common) and never shows higher than whatever it is stuck at temperature triggering ECU error once the ECU figures out that the temp should already be higher than what sensor shows. Unfortunately driving with this sensor shot has another side effect which is bad MPG since ECU is constantly running on warm up fueling which dumps additional fuel...
Fix it asap, it is very easy to swap and hopefully it fixes all of your issues.
05-03-2011, 09:13 AM
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thejulex is right. An Audi tech walked by me and I asked him about the switches you highlighted on your picture. 3 is, as you all know a very popular switch to replace. It sends a signal to the ECM and the temp gauge in the instrument cluster. He did say that 3a and 45 should be for the radiator fan but you should have one or the other. He was a bit unsure about #45 being on later cars though.
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05-04-2011, 07:23 AM
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This is all good stuff guys. I'm pretty sure I saw #45 when I crawled underneath the car last time, so by your email Jeff I might not have the 3a. I'll report back for posteriry when the job is complete.
The sensors were ordered from AudiUSA a couple of days ago, a very nice woman called me to remind me I also needed a couple of $1 o-rings, which was very much appreciated.
Looking forward to clearing this CEL...my wife drives the car 99%of the time but when I drive it I haven't noticed the mileage suffering, too badly anyway.
Hey Jeff, maybe off topic, but I noticed the charge showed up on my CC as Sunset Porsche-Audi. My daily driver is a 996 and I find I'm buying parts more and more often as the miles pile up (I'm at 105K miles now). You don't by chance carry the WEVO sport motor mounts do you?
Thanks for the advice everyone.
The sensors were ordered from AudiUSA a couple of days ago, a very nice woman called me to remind me I also needed a couple of $1 o-rings, which was very much appreciated.
Looking forward to clearing this CEL...my wife drives the car 99%of the time but when I drive it I haven't noticed the mileage suffering, too badly anyway.
Hey Jeff, maybe off topic, but I noticed the charge showed up on my CC as Sunset Porsche-Audi. My daily driver is a 996 and I find I'm buying parts more and more often as the miles pile up (I'm at 105K miles now). You don't by chance carry the WEVO sport motor mounts do you?
Thanks for the advice everyone.
Last edited by jwetering; 05-04-2011 at 07:27 AM.
05-04-2011, 02:37 PM
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Porsche is our sister dealership, we handle both Audi and Porsche OEM parts. So they won't handle the WEVO mounts or any other parts other than OEM for your 996. Yes, our invoices will have our dealership name on it. The audiUSAparts.com is attached to our online website and web order form. That's how our parts manager has designed the program to work. Probably to track sales, but it also provides an online account that is used for all sales so the parts are sold at discounted prices.
Because we are an Audi dealer it only allows us to sell the OEM parts. But we should be able to sell any OEM part for the best price. We won't be able to match aftermarket prices in some cases. I just found out suspension control arms are a great example where the aftermarket is very competitive on those parts.
Those 996's are nice cars, very fun and great handling. RMS and coolant tank issues on some of the earlier ones. 99-2001 for the most part, 02 and on have been much better on the RMS issue. Other than that they have been a good car. Almost forgot, intermediate shaft problems would grenade the early 996 engines, although that happened more to the Boxsters than the 996 it seemed to me. The aftermarket has a pretty good kit to help prevent or repair if possible, that IMS problem should your car be a candidate for that repair.
Because we are an Audi dealer it only allows us to sell the OEM parts. But we should be able to sell any OEM part for the best price. We won't be able to match aftermarket prices in some cases. I just found out suspension control arms are a great example where the aftermarket is very competitive on those parts.
Those 996's are nice cars, very fun and great handling. RMS and coolant tank issues on some of the earlier ones. 99-2001 for the most part, 02 and on have been much better on the RMS issue. Other than that they have been a good car. Almost forgot, intermediate shaft problems would grenade the early 996 engines, although that happened more to the Boxsters than the 996 it seemed to me. The aftermarket has a pretty good kit to help prevent or repair if possible, that IMS problem should your car be a candidate for that repair.
05-04-2011, 02:49 PM
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Thanks for the clarification Jeff.
Not to turn this into a Porsche thread....but that *is* my preferred weapon. I'm on my second 2002 996 at the moment and up until about 2007 I was an air cooled guy.
I'm really happy with my 996, nevermind the haters.
I've replaced the coolant tank in both of my 996, it was easier the second time around. $200 - no big deal. RMS hasn't been an issue for me. My first car had it's RMS replaced 4 times before I got the car though, and my current car had a reman motor installed in 2005. Reason for failure unknown.
The IMS issue doesn't keep me up at night, but I'm pretty sure I'll install the aftermarket bearing anyway when I do my clutch...perhaps next year.
My concern at the moment is whether a LWFW will really put me at risk of crankshaft failure as the scaremongers claim.
Overall I have to say the Porsche is more pleasant to work on than the Audi...a lot more.
Not to turn this into a Porsche thread....but that *is* my preferred weapon. I'm on my second 2002 996 at the moment and up until about 2007 I was an air cooled guy.
I'm really happy with my 996, nevermind the haters.
I've replaced the coolant tank in both of my 996, it was easier the second time around. $200 - no big deal. RMS hasn't been an issue for me. My first car had it's RMS replaced 4 times before I got the car though, and my current car had a reman motor installed in 2005. Reason for failure unknown.
The IMS issue doesn't keep me up at night, but I'm pretty sure I'll install the aftermarket bearing anyway when I do my clutch...perhaps next year.
My concern at the moment is whether a LWFW will really put me at risk of crankshaft failure as the scaremongers claim.
Overall I have to say the Porsche is more pleasant to work on than the Audi...a lot more.