CEL code leading V70 newbie on a ghost hunt! Experience needed!
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CEL code leading V70 newbie on a ghost hunt! Experience needed!
Let me start by saying that I am a jeep guy at heart and have owned several. We decided to go with Volvo because we needed more seats while keeping AWD and quality manufacturing. In my years of Jeepin' I got pretty used to diagnosing and fixing it myself. I expect to be able to do the same with this Volvo. That said, here's my story.
I bought a 2000 V70 SE AWD XC from a used seller/dealer in the state next door (170 mi one way). Fifteen mile test drive went without a hitch. So we bought it and headed home. Thirty miles from dealership my wife gases up and 3 miles later CEL comes on. I called the dealer and took a pic of the display with the light and miles. It was decided to continue home and check codes. He assured me that whatever it was would be dealt with and that his presale mechanic did not check codes, clear codes, or see a CEL on this car. I got codes pulled the next day with only one showing up, P0422, main catalyst threshold efficiency low, then cleared it. I came home and did some research (finding this site in the process) and found a bevy of possibilities for the fault. I called the seller/dealer and he suggested that if the code returns that I have a volvo dealer test it to make sure that no other codes are present. If not, he'll assume the cat is the problem and have the cat replaced by his regular guy, which is 170 miles away.
So, I began trying to make sense of all the posts and experiences on these two sites. I also tried to find a repair manual but could not find one for the 'American' version. There were suggestions to purchase a DVD online but I hesitate to do that due to mixed reviews and some evidence that leads me to suspect that information is spread over several discs and updates. I haven't looked further down that road.
Code came back after 20 miles and I took it to a Volvo dealership who confirmed the P0422 with their own ECM 4801 code and said I should replace the cat ($1700). They also said my timing belt was due ($1200) and a loose clamp on my PS reservoir ($110). With a straight face no less. I declined, bought some CHF 11s, tightened the clamp, topped off, and put researching the timing belt on my to-do list. Back to cat.
Now, everything I'm reading on this site and Matthews site indicates I should start by looking for intake/exhaust leaks, uneven compression, faulty fuel pressure etc. Hard to do without a tech book since I don't know what many of these sensors and specs are! Next I read that unburnt fuel (too rich) can be caused by a bad #1 O2 sensor and that extra fuel can ruin a cat. Or it could be a faulty #2 sensor. My current average MPG, according to the dash display is 16mpg (18.5 hwy, 14 city)(I reset it last weekend since it seemed to be stuck at 16.3 from the previous owner) I've read the many of these cars get into the mid to high 20's!
If it is the cat (which at 99k seems to be unlikely according to both forums) that opens a whole can of worms as to which cat I should replace it with. The seller/dealer seems convinced we should follow the code and replace the cat with an aftermarket unit which would involve a double car 340 mile round trip! Not to mention that 1.)it may not fix the problem 2.) The aftermarket cat will be of the dealers choosing and may fail after a short time which; 3.) could leave me with the same issue, a modified exhaust, and possibly more issues due the the real problem continuing to be a problem!
The seller/dealer has also offered to write me a check for what the total would be with his guy for replacing the cat (parts and labor) . Or have me write him a check for difference to get the OE part upgrade.
I really need some guru advice here. How do I best narrow the possibilities down? Does a lack of additional codes strongly indicate a cat failure? Are there ways to test the cat? the O2 sensors? MAF sensor? How do I test compression down in these deep plug holes? Or anything else that may help?
I bought a 2000 V70 SE AWD XC from a used seller/dealer in the state next door (170 mi one way). Fifteen mile test drive went without a hitch. So we bought it and headed home. Thirty miles from dealership my wife gases up and 3 miles later CEL comes on. I called the dealer and took a pic of the display with the light and miles. It was decided to continue home and check codes. He assured me that whatever it was would be dealt with and that his presale mechanic did not check codes, clear codes, or see a CEL on this car. I got codes pulled the next day with only one showing up, P0422, main catalyst threshold efficiency low, then cleared it. I came home and did some research (finding this site in the process) and found a bevy of possibilities for the fault. I called the seller/dealer and he suggested that if the code returns that I have a volvo dealer test it to make sure that no other codes are present. If not, he'll assume the cat is the problem and have the cat replaced by his regular guy, which is 170 miles away.
So, I began trying to make sense of all the posts and experiences on these two sites. I also tried to find a repair manual but could not find one for the 'American' version. There were suggestions to purchase a DVD online but I hesitate to do that due to mixed reviews and some evidence that leads me to suspect that information is spread over several discs and updates. I haven't looked further down that road.
Code came back after 20 miles and I took it to a Volvo dealership who confirmed the P0422 with their own ECM 4801 code and said I should replace the cat ($1700). They also said my timing belt was due ($1200) and a loose clamp on my PS reservoir ($110). With a straight face no less. I declined, bought some CHF 11s, tightened the clamp, topped off, and put researching the timing belt on my to-do list. Back to cat.
Now, everything I'm reading on this site and Matthews site indicates I should start by looking for intake/exhaust leaks, uneven compression, faulty fuel pressure etc. Hard to do without a tech book since I don't know what many of these sensors and specs are! Next I read that unburnt fuel (too rich) can be caused by a bad #1 O2 sensor and that extra fuel can ruin a cat. Or it could be a faulty #2 sensor. My current average MPG, according to the dash display is 16mpg (18.5 hwy, 14 city)(I reset it last weekend since it seemed to be stuck at 16.3 from the previous owner) I've read the many of these cars get into the mid to high 20's!
If it is the cat (which at 99k seems to be unlikely according to both forums) that opens a whole can of worms as to which cat I should replace it with. The seller/dealer seems convinced we should follow the code and replace the cat with an aftermarket unit which would involve a double car 340 mile round trip! Not to mention that 1.)it may not fix the problem 2.) The aftermarket cat will be of the dealers choosing and may fail after a short time which; 3.) could leave me with the same issue, a modified exhaust, and possibly more issues due the the real problem continuing to be a problem!
The seller/dealer has also offered to write me a check for what the total would be with his guy for replacing the cat (parts and labor) . Or have me write him a check for difference to get the OE part upgrade.
I really need some guru advice here. How do I best narrow the possibilities down? Does a lack of additional codes strongly indicate a cat failure? Are there ways to test the cat? the O2 sensors? MAF sensor? How do I test compression down in these deep plug holes? Or anything else that may help?
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From: Albuquerque, NM
Hi Adler: Welcome to the site and I'm glad you found us and MATT's site. They are both pretty good (Matt's site usually has faster response).
I usually take my code reader with me on all test drives. Really helps me check out a car, even if it has a bulb out at the CEL location.
As for your problem, P0422, since your system code points to the cat and the stealer said it's a cat, I would simply focus on replacing the cat. I have no experience with cat problems on these FWD Volvo's, I'm just telling you what I would do. Since the place you purchased the car from is offering to write you a check, my guess would be for about $300, I'd probably take it, or at least check to see what you could get one for around your place and try to get that amount (to avoid the trip down there). I would imagine that you could drive there, wait an hour for them to replace the cat and drive back. Yes I know that's 5 hours but it sure beats the heack out of $1,700. When the cat is replaced you will know that it's behind you and you can check on what caused the cat to go out. One of my neighbors had a cat go out in their 2000 VW wagon. They only used 91+ octane so I'm not sure what caused their failure.
Many things could cause unburned fuel in a piston. Number one being a bad plug, then gap not set right, old plugs, etc... The car is turbo and I'm pretty sure Volvo recommends 91+ octane.
As for the O2 sensors being bad, usually they could trigger a code. It doesn't mean that they didn't just replace a sensor 6 months ago after driving with a bad one for 5 years. That's the bad thing about not having the history. So I would do the cat, check the plugs (maybe replace them with oem plugs), and clean the MAF.
That gas mileage is horrable. My guess would be that you do not have OEM plugs. Check them first. These cars really do not like different plugs, other than OEM. You are not misfiring or you would have that code. You could have a vacuum leak but even with that I having seen gas mileage that bad. We have a thread in the 850 section about gas mileage. Also in the General Section.
As for the source of the cat, I would probably find a car that has a blown head gasket, broken timing belt or something like that and purchase their cat. You can often find people parting out wrecked cars here and on www.SwedeSpeed.com. There are 3 or 4 other Volvo sites you can check for used parts. I think it's kind of rare for cats to go out so you should be safe buying one from other people. My guess would be that you could get a cat from any 850 or S/V70 between '94 and '00. You can double check with others to be sure. I'm 98% sure you can use one from the '98 - '00 cars.
I think the timing belt on those cars are due at 105,000. Yes do that (many do but I don't change the water pump unless it's leaking). Also look into doing the PCV system. That can cause major problems.
If you look in the General Section you will find a link to get the real live Volvo repair manual from a guy here. I usually use the repair write-up that I find link around on these sites but do have a Mitchell Manual (cd).
Here is my thread for checking compression:
Compression Test - Volvo S70 GLT, 1998
You should also check the 850 New Owner thread. You'll get a lot of good info from it.
I had a Jeep for a few years and did enjoy it.
I usually take my code reader with me on all test drives. Really helps me check out a car, even if it has a bulb out at the CEL location.
As for your problem, P0422, since your system code points to the cat and the stealer said it's a cat, I would simply focus on replacing the cat. I have no experience with cat problems on these FWD Volvo's, I'm just telling you what I would do. Since the place you purchased the car from is offering to write you a check, my guess would be for about $300, I'd probably take it, or at least check to see what you could get one for around your place and try to get that amount (to avoid the trip down there). I would imagine that you could drive there, wait an hour for them to replace the cat and drive back. Yes I know that's 5 hours but it sure beats the heack out of $1,700. When the cat is replaced you will know that it's behind you and you can check on what caused the cat to go out. One of my neighbors had a cat go out in their 2000 VW wagon. They only used 91+ octane so I'm not sure what caused their failure.
Many things could cause unburned fuel in a piston. Number one being a bad plug, then gap not set right, old plugs, etc... The car is turbo and I'm pretty sure Volvo recommends 91+ octane.
As for the O2 sensors being bad, usually they could trigger a code. It doesn't mean that they didn't just replace a sensor 6 months ago after driving with a bad one for 5 years. That's the bad thing about not having the history. So I would do the cat, check the plugs (maybe replace them with oem plugs), and clean the MAF.
That gas mileage is horrable. My guess would be that you do not have OEM plugs. Check them first. These cars really do not like different plugs, other than OEM. You are not misfiring or you would have that code. You could have a vacuum leak but even with that I having seen gas mileage that bad. We have a thread in the 850 section about gas mileage. Also in the General Section.
As for the source of the cat, I would probably find a car that has a blown head gasket, broken timing belt or something like that and purchase their cat. You can often find people parting out wrecked cars here and on www.SwedeSpeed.com. There are 3 or 4 other Volvo sites you can check for used parts. I think it's kind of rare for cats to go out so you should be safe buying one from other people. My guess would be that you could get a cat from any 850 or S/V70 between '94 and '00. You can double check with others to be sure. I'm 98% sure you can use one from the '98 - '00 cars.
I think the timing belt on those cars are due at 105,000. Yes do that (many do but I don't change the water pump unless it's leaking). Also look into doing the PCV system. That can cause major problems.
If you look in the General Section you will find a link to get the real live Volvo repair manual from a guy here. I usually use the repair write-up that I find link around on these sites but do have a Mitchell Manual (cd).
Here is my thread for checking compression:
Compression Test - Volvo S70 GLT, 1998
You should also check the 850 New Owner thread. You'll get a lot of good info from it.
I had a Jeep for a few years and did enjoy it.
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Thank you so much for taking the time to write all that up rspi. I'm going to check the plugs and compression today. Then I'll pull the sensors and clean them. If that points no where I'll go buy a code reader and spend some time with that. Thanks for the lead on a repair manual. How do you like your CD version?
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I did plug check and cylinder compression test today. All plugs looked good except #4. On that one the electrode looked good but the ceramic end was coated with a thin layer of brown schmutz, and there was more in the boot. Looked like cooked engine oil. I cleaned them both up and made a note of it.
Compression test went well (thanks for the link!) and the results were;
#1-190
#2-185
#3-180
#4-180
#5-190
None showed and bleed down. I did get a small whif of fuel after number three but got closer and really smelled and got no more.
So, I put the modules back on. #2 kept popping back off so I bolted it down and moved onto the MAF test. Here are those results;
Engine idling @1100 (Normal for this car)
Disconnect (DC) MAF pigtail, engine hiccups once, smooths out, idle now @900.
Reconnect (RC) MAF, 5 second delay then idle ups to 1000.
DC MAF again, engine hiccups once, dies.
RC MAF, restart engine, idle @900
DC MAF, engine dies, then hiccups
RC MAF, restart engine, idle @ 900
Anything here that points in a particular direction?
Compression test went well (thanks for the link!) and the results were;
#1-190
#2-185
#3-180
#4-180
#5-190
None showed and bleed down. I did get a small whif of fuel after number three but got closer and really smelled and got no more.
So, I put the modules back on. #2 kept popping back off so I bolted it down and moved onto the MAF test. Here are those results;
Engine idling @1100 (Normal for this car)
Disconnect (DC) MAF pigtail, engine hiccups once, smooths out, idle now @900.
Reconnect (RC) MAF, 5 second delay then idle ups to 1000.
DC MAF again, engine hiccups once, dies.
RC MAF, restart engine, idle @900
DC MAF, engine dies, then hiccups
RC MAF, restart engine, idle @ 900
Anything here that points in a particular direction?
Last edited by AdlerV70; Dec 30, 2011 at 04:51 PM. Reason: to remove a cry for help on a missing cylinder. When I re-bolted down the spark modules I pinch a wire for the #4 module unde
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From: Albuquerque, NM
That is really good compression, Hurrah!!! I really don't know anything about the MAF checks you preformed.
Did you have OEM plugs? You know, it would not be far fetched for them to be the original plugs that came in the car. These cars run pretty smooth with old plugs and there is a chance that they were NEVER changed.
As to the junk on your #4 plug, you may have had a slight leak on a valve or piston at one time. Could also be a very small head gasket leak. I would not worry about it with that kind of compression. Just keep your oil changes up, keep the coolant change every couple of years and run fuel injector cleaner in it every 5,000 (10,000 if you drive a lot - more than 25,000 per year) miles and you should be good.
My manual helps a little. Mostly use it for reasearch, torque specs, and stuff like that. The DIY write up do me more good than the manual. I'm pretty slow with vauge instructions and do enjoy the photos and feedback.
Did you have OEM plugs? You know, it would not be far fetched for them to be the original plugs that came in the car. These cars run pretty smooth with old plugs and there is a chance that they were NEVER changed.
As to the junk on your #4 plug, you may have had a slight leak on a valve or piston at one time. Could also be a very small head gasket leak. I would not worry about it with that kind of compression. Just keep your oil changes up, keep the coolant change every couple of years and run fuel injector cleaner in it every 5,000 (10,000 if you drive a lot - more than 25,000 per year) miles and you should be good.
My manual helps a little. Mostly use it for reasearch, torque specs, and stuff like that. The DIY write up do me more good than the manual. I'm pretty slow with vauge instructions and do enjoy the photos and feedback.
Last edited by rspi; Dec 30, 2011 at 08:01 PM. Reason: addition
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Joined: Jul 2008
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From: Pac NW
AdlerV70: This P0422 can be caused by lots of things besides the cat converter. Here's one thread as an example of what I'm talking about:
https://volvoforums.com/forum/volvo-...ymptoms-54000/
If I were in your shoes, i would find a good/recommended local indy volvo tech and have him ck it out completely (i.e. find all the problems; BTW should have done this before you bought it..). Hopefully the fix(es) won't break your wallet.
Then, when all is good, go back to the selling dealer with your work receipts; if he's got any reputation at all he should pay for at least half.
Also, kind of cryptic, but found this utube informative on the topic:
http://www.youtube.com/watch?v=nJ0G01nlFRo
https://volvoforums.com/forum/volvo-...ymptoms-54000/
If I were in your shoes, i would find a good/recommended local indy volvo tech and have him ck it out completely (i.e. find all the problems; BTW should have done this before you bought it..). Hopefully the fix(es) won't break your wallet.
Then, when all is good, go back to the selling dealer with your work receipts; if he's got any reputation at all he should pay for at least half.
Also, kind of cryptic, but found this utube informative on the topic:
http://www.youtube.com/watch?v=nJ0G01nlFRo
Last edited by gdog; Dec 31, 2011 at 12:12 AM.
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Gdog,
The video was excellent! Took a minute to understand the cadence of the voice synth program but once I got that the information was pretty straight forward. The message essentially is, in the case of a pO420 or pO422 the first step should be too use an oscilloscope to measure the values of the two O2 sensors in real time. The upstream sensor should oscillate In a regular rise and fall pattern (mimicking the the exhausting of each cylinder for each rise) and the downstream sensor should read a steady voltage around .46 volts. Any variation points to s specific issue.
Now I just need a code reader that can perform this function! Anyone have one that does? If so, whats the make and model?
Thanks!
The video was excellent! Took a minute to understand the cadence of the voice synth program but once I got that the information was pretty straight forward. The message essentially is, in the case of a pO420 or pO422 the first step should be too use an oscilloscope to measure the values of the two O2 sensors in real time. The upstream sensor should oscillate In a regular rise and fall pattern (mimicking the the exhausting of each cylinder for each rise) and the downstream sensor should read a steady voltage around .46 volts. Any variation points to s specific issue.
Now I just need a code reader that can perform this function! Anyone have one that does? If so, whats the make and model?
Thanks!
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Awesome! I have one of those! Not sure why I didn't think of that
...
I assume the engine doesn't need to be under load to test it. Just bring it up to temp, and check the voltage on the down stream sensor for proper voltage.
Related question: If the oscillations for the upstream sensor are truly representative of the pulses of exhaust from the valves, does it follow that an irregularity in the oscillations would indicate a problem that must be limited to somewhere between the exhaust valves and the sensor itself? Any intake leak would not be picked up by that sensor insofar as the oscillations are concerned. True?
...I assume the engine doesn't need to be under load to test it. Just bring it up to temp, and check the voltage on the down stream sensor for proper voltage.
Related question: If the oscillations for the upstream sensor are truly representative of the pulses of exhaust from the valves, does it follow that an irregularity in the oscillations would indicate a problem that must be limited to somewhere between the exhaust valves and the sensor itself? Any intake leak would not be picked up by that sensor insofar as the oscillations are concerned. True?
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