Afternoon.
A lot has been written about MAF sensor. I have been having problems which pointed to a bad MAF sensor but I really wanted to try to test it before I would spend over $100 on a new one. Found a post where it said the feed-back voltage should be between 1-2 V at idle, and then go up from there when the throttle is pressed. Has anyone done this exact test on 2001 V70? The terminals are very small and not easy to work with but I rigged up test cords and measured between terminal 2 and 4, and got around 3.24V at idle, which I assume is too much. I took it out and tried to clean it the best I could and reinstalled, same output voltage. I monkyed with it some more but gave up and plugged everything together. Well, I must have done some harm to it because now the car runs terrible and all the codes in book are coming up, including STC Service Required in the message center. I was very careful not to touch the sensor wires, but maybe I accidentally shorted across terminals in the connector when I was probing. I hope I didn't fry any computers or other electrical items in the process. Any thoughts what may have gone south on me?
So if the MAF sensor wasn't bad before, I may have managed to wreck it. There are 5 terminals. No wire to no 1. I assume 2 and 4 to be the feedback voltage and then one for input voltage and ground. Does anyone have a diagram for this? So now I assume I will have to put in a new MAF sensor and go from there. I suspect there are some other issues as I was getting P0234 over boost code as well.
So in summary:
1. Anyone have a diagram for the wires going into the MAF sensor?
2. Anyone been successful in confirming if the sensor was good or bad by using multimeter?
3. Could I have done some major damage?
4. Anyone know where one can get a Bosch 0280218088 for under $100?
Thanks in advance,
Emil
How to test MAF sensor problems?
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JimBee
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I have posted several times on this, regarding the 850. Like you, I didn't want to spend a bunch of money on a sensor that wouldn't fix my erratic idle and running problems.
Here's what I found:
http://easyautodiagnostics.com/Volvo-MA ... est-c.html
I don't know if the system is the same for your car, I'm guessing it's close.
In any case, what you want to test for is not just idle voltage, but smooth increase that corresponds in terms of electrical voltage to air mass (quantity) coming through your airbox and into the engine. That means the engine needs to be running when you test. The MAF voltage tells the computer how much fuel to call into the cylinders for the perfect mix. But at the end of that loop, you also get feedback from your oxygen sensor for a final tweaking of the fuel/air ratio — as I understand it.
Maybe that diagram and writeup will help.
To test, You need a multimeter and 2 1-inch long nails, the kind with a head on them. If you peel back the boot on the MAF connector, you'll see pin numbers stamped into the plug. Two are grounds on the 850. One ground goes to the main computer, the other to battery ground. You'll want to FIRST confirm which pins correspond to grounds and voltage on your car.
Make sure your MAF contacts are clean. With negative battery cable disconnected, clean them with something non-conductive, then add a dab of dialectric grease and plug connector back together securely.
You use your multi-meter to measure voltage across the voltage pin and the ground pin. The safest and maybe only way to get readings with the engine running is to use the small nails to probe the contacts from outside of the plug. The writeup suggests using an insulation puncture test probe. I use the nails instead. Just slide them under the rubber insulator from outside of the plug until they bottom at the metal pin inside. Then use test leads with alligator clips to connect your multimeter.
Reconnect your battery ground and start the engine MAKING SURE the test leads are kept separated. Your meter should be set at DC voltage on a low scale. The voltage should be low and stable at idle and smoothly increase as you increase the rpm's to around 4.5 volts if I recall correctly). If it's much higher or lower than those readings at either high or low rpm—or if it jumps around at any point on the rpm curve— then the MAF probably needs to be replaced. Keep in mind, every fluctuation of the voltage at a given rpm is a fluctuation in the computer calling for fuel.
I had that problem PLUS I discovered dirty oxygen sensor contacts which was making the computer (and engine) erratic.
RE: non-Bosch MAF.
I will experiment with things. I know the gospel on Volvo sensors says you'll be sorry if you don't use Bosch. Well I bought the Cardone remanufactured (from JC Whitney I think) after looking into a bit. I think the Rock Auto sells it too and the company has a fairly convincing spiel about how its element is heavily soldered to avoid vibration failure, etc.
I actually have them on two 850's, one of which has very few miles on the sensor, the other of which has several thousand and no problems.
Anyway, make sure you check your O2 sensor connector and the terminals are clean. A dab of dialectric grease on all terminals can give a little extra assurance. My understanding from my personal experience is that a bad O2 sensor will harm your gas mileage but won't cause serious engine malfunction (though I've been told by one tech it can, still not sure of consensus on that) but in my experience if the contacts are poor enough they won't pass voltage or resistance—IOW no or weak continuity that will give you erratic engine performance.
The final thing to keep in mind is with all sensors doing their job, if the computer was doing whacky things before you corrected the sensor issues, you have to allow the computer to reset itself. If you jiggle the accelerator trying to keep the engine running, you can defeat the computer from stabilizing. If you can get it started, just let it roll up and down a bit, even if you think it's going to stall—and it might—let it be. Restart it if it stalls and let it alone again to see if it will straighten out.
Good luck.
Here's what I found:
http://easyautodiagnostics.com/Volvo-MA ... est-c.html
I don't know if the system is the same for your car, I'm guessing it's close.
In any case, what you want to test for is not just idle voltage, but smooth increase that corresponds in terms of electrical voltage to air mass (quantity) coming through your airbox and into the engine. That means the engine needs to be running when you test. The MAF voltage tells the computer how much fuel to call into the cylinders for the perfect mix. But at the end of that loop, you also get feedback from your oxygen sensor for a final tweaking of the fuel/air ratio — as I understand it.
Maybe that diagram and writeup will help.
To test, You need a multimeter and 2 1-inch long nails, the kind with a head on them. If you peel back the boot on the MAF connector, you'll see pin numbers stamped into the plug. Two are grounds on the 850. One ground goes to the main computer, the other to battery ground. You'll want to FIRST confirm which pins correspond to grounds and voltage on your car.
Make sure your MAF contacts are clean. With negative battery cable disconnected, clean them with something non-conductive, then add a dab of dialectric grease and plug connector back together securely.
You use your multi-meter to measure voltage across the voltage pin and the ground pin. The safest and maybe only way to get readings with the engine running is to use the small nails to probe the contacts from outside of the plug. The writeup suggests using an insulation puncture test probe. I use the nails instead. Just slide them under the rubber insulator from outside of the plug until they bottom at the metal pin inside. Then use test leads with alligator clips to connect your multimeter.
Reconnect your battery ground and start the engine MAKING SURE the test leads are kept separated. Your meter should be set at DC voltage on a low scale. The voltage should be low and stable at idle and smoothly increase as you increase the rpm's to around 4.5 volts if I recall correctly). If it's much higher or lower than those readings at either high or low rpm—or if it jumps around at any point on the rpm curve— then the MAF probably needs to be replaced. Keep in mind, every fluctuation of the voltage at a given rpm is a fluctuation in the computer calling for fuel.
I had that problem PLUS I discovered dirty oxygen sensor contacts which was making the computer (and engine) erratic.
RE: non-Bosch MAF.
I will experiment with things. I know the gospel on Volvo sensors says you'll be sorry if you don't use Bosch. Well I bought the Cardone remanufactured (from JC Whitney I think) after looking into a bit. I think the Rock Auto sells it too and the company has a fairly convincing spiel about how its element is heavily soldered to avoid vibration failure, etc.
I actually have them on two 850's, one of which has very few miles on the sensor, the other of which has several thousand and no problems.
Anyway, make sure you check your O2 sensor connector and the terminals are clean. A dab of dialectric grease on all terminals can give a little extra assurance. My understanding from my personal experience is that a bad O2 sensor will harm your gas mileage but won't cause serious engine malfunction (though I've been told by one tech it can, still not sure of consensus on that) but in my experience if the contacts are poor enough they won't pass voltage or resistance—IOW no or weak continuity that will give you erratic engine performance.
The final thing to keep in mind is with all sensors doing their job, if the computer was doing whacky things before you corrected the sensor issues, you have to allow the computer to reset itself. If you jiggle the accelerator trying to keep the engine running, you can defeat the computer from stabilizing. If you can get it started, just let it roll up and down a bit, even if you think it's going to stall—and it might—let it be. Restart it if it stalls and let it alone again to see if it will straighten out.
Good luck.
Thank you JimBee.
Yes, I did find a post where they used the “nail” method. It doesn’t look like that can be used with this model of a sensor. The terminals are very tiny and thin, couldn’t even fit a 18 gauge staple into the female. I did make test wires with alligator clip on one end and clamped it to the male terminal and on the other end I had a small blade terminal I could insert into the female end (i.e. the harness). But it wasn’t the best of a setup and I think the piercing probes would be a better bet.
Now the big question is if it is possible that I fried the ECU?? What if my ten-thumb-probing accidently sent 12V into the feedback terminal into the ECU? Would it toast it? Something happened for sure as I got numerous new codes stating pretty much everything with the fuel/air/exhaust system was gone amiss. I tried to clear the codes out, but they just came back, different codes, sometimes 6 or 8, sometimes 12 or 13. Is there some “reset” I can do? Battery disconnect? Fuse removal?
I am going to have to keep plugging along with this, but I sure hope I didn’t fry the ECU. I haven’t checked how much they are, but I know they aren’t cheap.
Thanks,
Emil
Yes, I did find a post where they used the “nail” method. It doesn’t look like that can be used with this model of a sensor. The terminals are very tiny and thin, couldn’t even fit a 18 gauge staple into the female. I did make test wires with alligator clip on one end and clamped it to the male terminal and on the other end I had a small blade terminal I could insert into the female end (i.e. the harness). But it wasn’t the best of a setup and I think the piercing probes would be a better bet.
Now the big question is if it is possible that I fried the ECU?? What if my ten-thumb-probing accidently sent 12V into the feedback terminal into the ECU? Would it toast it? Something happened for sure as I got numerous new codes stating pretty much everything with the fuel/air/exhaust system was gone amiss. I tried to clear the codes out, but they just came back, different codes, sometimes 6 or 8, sometimes 12 or 13. Is there some “reset” I can do? Battery disconnect? Fuse removal?
I am going to have to keep plugging along with this, but I sure hope I didn’t fry the ECU. I haven’t checked how much they are, but I know they aren’t cheap.
Thanks,
Emil
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JDS60R
- MVS Moderator
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- Year and Model: 2007 S60R 2016 XC70
- Location: Mount Juliet, TN
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Emil,
Attached is the specifications for your cars sensors. MAF is 1.0v DC when on 1.7Vdc when idling and voltage increases on increase in airflow.
More to follow on your sensor
Attached is the specifications for your cars sensors. MAF is 1.0v DC when on 1.7Vdc when idling and voltage increases on increase in airflow.
More to follow on your sensor
- Attachments
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2001 v701 2.4T sensor specification.pdf- (92.06 KiB) Downloaded 1396 times
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JDS60R
- MVS Moderator
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- Year and Model: 2007 S60R 2016 XC70
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!!!!!!!!!!!!Edited by JDS60R - This is not the correct sensor see later posts - use 0280218108 for 01 V70 2.4T !!!!!!!!!!!!!!
Best i could find is $126 delivered.
https://www.amazon.com/Bosch-0280218088- ... automotive
Call FCP to see if they can beat pricing.
Best i could find is $126 delivered.
https://www.amazon.com/Bosch-0280218088- ... automotive
Call FCP to see if they can beat pricing.
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Thank you JDS60R
After diggin a bit deeper into the part numbers I found this out:
A. The MAF in the car now is Bosch 0280218045
B. The MAF that Rock Auto comes up with is 0280218088 which is for 01-07 model
C. But then I also found 0280218108 which is for 99-01 model year, and I found in one place that the 108 is a replacement for the 045. Must be a swich-over on pn somewhere along the 01 model year. Same sensor or should I stick with the 108?
Also, would you happen to know:
1. Do you happen to have desingations for the terminals, 1-5 (1 not being used)?
2. Could I have done damage to the ECU and how would I know?
Thanks,
Emil
After diggin a bit deeper into the part numbers I found this out:
A. The MAF in the car now is Bosch 0280218045
B. The MAF that Rock Auto comes up with is 0280218088 which is for 01-07 model
C. But then I also found 0280218108 which is for 99-01 model year, and I found in one place that the 108 is a replacement for the 045. Must be a swich-over on pn somewhere along the 01 model year. Same sensor or should I stick with the 108?
Also, would you happen to know:
1. Do you happen to have desingations for the terminals, 1-5 (1 not being used)?
2. Could I have done damage to the ECU and how would I know?
Thanks,
Emil
-
JDS60R
- MVS Moderator
- Posts: 3532
- Joined: 21 February 2009
- Year and Model: 2007 S60R 2016 XC70
- Location: Mount Juliet, TN
- Been thanked: 3 times
I would doubt the ECM was damaged .
Not sure what you mean on the terminals. Wiring diagrams are above in the repair database. If you have a 3 wire its usually supply voltage on one pin , output voltage 'U" on another and then a ground. Just ground your voltage meter to the battery and test the pins on a DC volts scale. You will find the right one without damage. If you have a 4th its for "U" on intake air temp. Some also have 5 pins. I checked your MAF number at BOSCH itself and your original number was correct.
Here is the BOSCH company resource.
!!!!!!!!!!!!Edited by JDS60R - This is not the correct sensor see later posts - use 0280218108 for 01 V70 2.4T !!!!!!!!!!!!!!
http://www.boschautoparts.com/VehiclePa ... inder.aspx
Not sure what you mean on the terminals. Wiring diagrams are above in the repair database. If you have a 3 wire its usually supply voltage on one pin , output voltage 'U" on another and then a ground. Just ground your voltage meter to the battery and test the pins on a DC volts scale. You will find the right one without damage. If you have a 4th its for "U" on intake air temp. Some also have 5 pins. I checked your MAF number at BOSCH itself and your original number was correct.
Here is the BOSCH company resource.
!!!!!!!!!!!!Edited by JDS60R - This is not the correct sensor see later posts - use 0280218108 for 01 V70 2.4T !!!!!!!!!!!!!!
http://www.boschautoparts.com/VehiclePa ... inder.aspx
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