740 ccodes 2-3-1 and2-2-1

  #1  
Old 10-14-2011, 08:21 AM
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Default 740 ccodes 2-3-1 and2-2-1

I just picked up a cream puff 89 740 GL non turbo the other day to use as my daily driver. It has 106,000 miles and seem to run great. The only problem is a persistent check engine light. When I pull the codes it tells me 2-3-1 and 2-2-1 . From what I have found both codes seem to point to the O2 sensor. The O2 sensor was replaced at 105,000 along with fuel filter, air filter, plugs, wires, and the throttle body was removed and cleaned/repaired. So my question is what else could throw this code? It does run and drive fine with no noticeable problem- perhaps the MPG are a little low at 23 highway? This is my first Volvo and I want to keep it going great for as long as possible. Any help would be greatly appreciated.
Thanks,
 
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Old 10-14-2011, 09:31 AM
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One other item to check for is exhaust leaks upstream of the O2 sensor. Any leaks upstream of the sensor lets in oxygen that fools the ECU to thinking that there is a lean condition and will enrich the mixture.

Your mileage is slightly low but not too much. On my 240 (basically same engine/transmission), I tend to get around 23 in mixed driving. I would expect 25+ on pure highway driving but my car rarely takes long enough trips to take a good highway measurement.
 
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Old 10-14-2011, 02:43 PM
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Originally Posted by sfmitchell3 View Post
I just picked up a cream puff 89 740 GL non turbo the other day to use as my daily driver. It has 106,000 miles and seem to run great. The only problem is a persistent check engine light. When I pull the codes it tells me 2-3-1 and 2-2-1 . From what I have found both codes seem to point to the O2 sensor. The O2 sensor was replaced at 105,000 along with fuel filter, air filter, plugs, wires, and the throttle body was removed and cleaned/repaired. So my question is what else could throw this code? It does run and drive fine with no noticeable problem- perhaps the MPG are a little low at 23 highway? This is my first Volvo and I want to keep it going great for as long as possible. Any help would be greatly appreciated.
Thanks,
OK do we assume you reset the codes ? First try that and then start the car and drive it for a few miles and then see if you get a code again. The 1st code is usually the problem area and usually will set an addition code or two. The codes are stacked so when you read them the last code that comes up is the issue. So it sounds like 2-2-1 is the problem. So you could have a bad or wrong O2 sensor or an air or vacuum leak on one of the hoses. Also check the MAF sensor ground point as well as checking the MAF. Try unpluging and repluging the sensor. We have an 89 740 GL with 317K miles and it runs great. we usually get 24mpg avg.
 
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Old 10-14-2011, 05:08 PM
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Thanks for the quick responses, I did reset the codes and they came back after about 50 miles or so. I checked for exhaust leaks and found nothing. Pardon my ignorance but where is the maf sensor located? I also noticed a bit of oil leaks from the oil filler cap. Gonna buy a new cap but perhaps there is too much crankcase pressure? Could this set off the code. Thanks again for the help so far.
 
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Old 10-14-2011, 09:27 PM
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Originally Posted by sfmitchell3 View Post
Thanks for the quick responses, I did reset the codes and they came back after about 50 miles or so. I checked for exhaust leaks and found nothing. Pardon my ignorance but where is the maf sensor located? I also noticed a bit of oil leaks from the oil filler cap. Gonna buy a new cap but perhaps there is too much crankcase pressure? Could this set off the code. Thanks again for the help so far.
I think all of these motors have blow by causing higher crankcase pressures. I would check the flame trap to make sure it is not plugged up. Start looking for vacuum leaks and any hoses may be leaking. The MAf sensor is near the front right side on the air breather hose. It is a cylinder about 4" long with a connector on it. Just unplug and re-plug it in. you should do the same with the TPS switch located on the throttle body. do the same. oh you don't need to buy a new cap just replace the rubber ring underneath the cap.
 
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Old 10-15-2011, 06:22 PM
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So checked for vacuum leaks and couldn't find any. Pulled the plug on the MAF and TPS plugged them back in. Pulled the flame trap and cleaned it with carb cleaner although it looked pretty clean already. Cleared the codes and started it up. It ran rough at start up and almost stalled out- check engine light came back on. Drove it for about 20 mile and it ran a bit rough especially at idle but seemed to smooth out for the last 5 miles or so. Checked the codes when I got back home 1-1-3 and 2-3-2 . Oh and still getting a small amount of oil leaking from the cap even thought the rubber seal looks good?
 
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Old 10-16-2011, 09:08 AM
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Originally Posted by sfmitchell3 View Post
So checked for vacuum leaks and couldn't find any. Pulled the plug on the MAF and TPS plugged them back in. Pulled the flame trap and cleaned it with carb cleaner although it looked pretty clean already. Cleared the codes and started it up. It ran rough at start up and almost stalled out- check engine light came back on. Drove it for about 20 mile and it ran a bit rough especially at idle but seemed to smooth out for the last 5 miles or so. Checked the codes when I got back home 1-1-3 and 2-3-2 . Oh and still getting a small amount of oil leaking from the cap even thought the rubber seal looks good?
So now you have 2 different codes , correct?This still points to the O2 sensor and all of the other vacuum leaks or exhaust leaks. It is strange that the idle is rough after you unplugged these 2 connectors. Check to make sure that you didn't bend a pin. Also I would consider resetting the TPS. This is critical in the idle circuit. Also it might be time to remove the throttle body and clean it. This usually gets crudded up from the PCV system. Also there is a process where you disconnect and short out 2 pins on the TPS and disconnect and plug the IAC valve and set the idle to 500rpm. I do this proceedure after I clean the TB and adjust the TPS. Then the system usually brings the idle to 750rpm. You may also have to clean the IAC. As to the rubber seal on the cap they always look good buy usuall dry out and not seal good. Just replace it.
 
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Old 10-16-2011, 10:26 AM
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Originally Posted by jagtoes View Post
So now you have 2 different codes , correct?This still points to the O2 sensor and all of the other vacuum leaks or exhaust leaks. It is strange that the idle is rough after you unplugged these 2 connectors. Check to make sure that you didn't bend a pin. Also I would consider resetting the TPS. This is critical in the idle circuit. Also it might be time to remove the throttle body and clean it. This usually gets crudded up from the PCV system. Also there is a process where you disconnect and short out 2 pins on the TPS and disconnect and plug the IAC valve and set the idle to 500rpm. I do this proceedure after I clean the TB and adjust the TPS. Then the system usually brings the idle to 750rpm. You may also have to clean the IAC. As to the rubber seal on the cap they always look good buy usuall dry out and not seal good. Just replace it.
Thanks for all your help. Pretty big learning curve. The throttle body was cleaned professionally about 1000 miles ago so I think it should be ok. I'm going to try to test the 02 sensor to see if it is good even though it is new. How do you reset the TPS? What is the IAC?
Thanks again for the help.
 
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Old 10-16-2011, 06:29 PM
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Originally Posted by sfmitchell3 View Post
Thanks for all your help. Pretty big learning curve. The throttle body was cleaned professionally about 1000 miles ago so I think it should be ok. I'm going to try to test the 02 sensor to see if it is good even though it is new. How do you reset the TPS? What is the IAC?
Thanks again for the help.

The internet is your friend. Engine Tune and Performance:
 
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Old 10-16-2011, 06:35 PM
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Old 10-20-2011, 05:09 PM
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Ok, thanks for the info. Cleaned the maf, now it runs worse than before. Car shakes when put in gear? On to the IAC etc...
 
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Old 10-20-2011, 06:18 PM
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Originally Posted by sfmitchell3 View Post
Ok, thanks for the info. Cleaned the maf, now it runs worse than before. Car shakes when put in gear? On to the IAC etc...

You can unplug the TPS and jumper out 2 of the pins. I don't recall what pins . Disconnect the large IAC hose and plug the hose. You should be able to start the car and reset the idle to 500rpm and it should be a smooth idle. This takes the IAC out of the loop.
 
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Old 11-12-2014, 05:04 PM
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I hate when threads end like this with no resolution posted. my 240 is running great but throwing codes 231 and 221 (like the 740 in the original post of this thread).

The airbox thermostat was non-functional when I bought the car, I've deleted the airbox thermostat and valve, cleaned the AMM and the throttle body. Afterward I had no codes for a few days and then a CEL and 231 and 221 came up.

I would not be surprised if this car was in need of a new O2 sensor - would that be your guess? If that's very likely I'll go buy and install one, but if that's just one of many possible 231 and 221 code causes then please advise.

Thank you!
 
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Old 11-12-2014, 06:08 PM
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re: airbox thermostat, you want to leave the flap in there, wired shut. or, cap off the pipe opening.
 
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