Check Engine Light - I need advice. Topic is solved

larrycrilley · Post by **larrycrilley** » 23 Mar 2009, 21:00

I have a 2001 v70xc and the check engine light came on and it had began running rough. I checked here on this forum and it seemed like a good cleaning of the MAF sensor might help. I used the cleaner (CRC MAF cleaner) and reassembled every thing and the CEL & rough idle continued.
I came back to the forum and took the advice to a take the car to AutoZone to have the codes read. The codes were P1171 and P0303. P1171 is for the MAF sensor and P0303 is a misfire on the #3 cylander.
My Questions are:
1). Is the misfire due to the sensor since they both happened at the same time?
2). Should have the codes been reset after the cleaning? Would this eliminate the CEL & rough running?
3). Do I go for the new sensor then reset the code?
4). How do I reset the codes?
5). Is there more I should know?
Thanks for the help in advance.

mijo850glt96 · Post by **mijo850glt96** » 23 Mar 2009, 21:29

1) not necessarily because the misfire could be traced to a bag spark plug gap or wire, which in the end can lead to an electrical problem with the distributor.
2)I would not say that just cleaning the MAF would clear the codes and engine light because many times its a preliminary step. The worse outcome is that the MAF is damaged and reading incorrectly, or the rough running could be a completely unrelated problem.
The way I see it is if you are having a spark problem with the 3rd cylinder try to find the problem and fix that. If the car is misfire it would respond with a loss of power and sometimes there will be black smoke coming out of the exhaust. If you can fix the misfire it would tell you if your MAF is truly broken.

SilverBullet · Post by **SilverBullet** » 23 Mar 2009, 23:18

I had a Subaru that did the same thing.. read the code it was a misfire in cylinder 3.. ended up being i just need to replace the plugs.. like i said that was a Subaru and not a Volvo. As for the MAF like he said above.. you will know more when the misfire is gone, like if the MAF is damaged or something

Tapsa · Post by **Tapsa** » 24 Mar 2009, 02:40

Hi,
in addition to plug#3 try to swap the coil to see wether the misfire is moving with it. clean the maf connector as well.
br Tapsa

George · Post by **George** » 17 Dec 2009, 06:47

Hello larrycrilly, So, what was the outcome? We'd (I'd) love to hear if you tracked it down correctly. CHEERS, George

larrycrilley · Post by **larrycrilley** » 17 Dec 2009, 18:52

Thanks for all the advice and help' I swapped out the the coil ($75.00 dealer part) and my problems were solved. I cleaned the MAF sensor and it was no longer an issue. Went to my local Autozone and reset my light. All is well with my wonderful XC70!

z28chuck400hp · Post by **z28chuck400hp** » 27 Dec 2009, 12:27

trying to solve a problem with my 2001 xc. I have found that if you disconnect the battery for 30 min. and turn the key on, then reconnect the battery, the check engine light turns off....it comes back on if the problem still exists...worth a try let me know if this works for you