Error code P0101
November 1st, 2020, 11:29 AM
#1
Error code P0101
Hello Forum.
This is the second time I get a P0101 code after a 5 hour drive. It only has happened when altitude changes are noticeable (more than 1 mile). Error goes away after a couple of days driving in Town.
Any experience with this scenario?
This is the second time I get a P0101 code after a 5 hour drive. It only has happened when altitude changes are noticeable (more than 1 mile). Error goes away after a couple of days driving in Town.
Any experience with this scenario?
November 1st, 2020, 12:09 PM
#2
Trouble codes can be easily looked up by searching online. P0101 is MAF sensor malfunction. (Mass Air Flow). So the computer thinks it isn't working properly. At high altitude the air gets thinner and the engine needs to lean out the mixture.
Re-seat the MAF connector. If that doesn't help then clean it out. It's a very sensitive part so don't touch or rub it. Just spray it liberally using a zero-residue cleaner. If you have them, things like electrical contact cleaner or brake parts cleaner will work. If not, the auto parts store sells specific MAF sensor cleaner but it's probably a waste of money because it'll just sit unused on your shelf for years.
The MAF shouldn't really be getting dirty in the first place, so check your air filter too.
Re-seat the MAF connector. If that doesn't help then clean it out. It's a very sensitive part so don't touch or rub it. Just spray it liberally using a zero-residue cleaner. If you have them, things like electrical contact cleaner or brake parts cleaner will work. If not, the auto parts store sells specific MAF sensor cleaner but it's probably a waste of money because it'll just sit unused on your shelf for years.
The MAF shouldn't really be getting dirty in the first place, so check your air filter too.
November 1st, 2020, 12:26 PM
#3
CF Veteran
Is that the only code you’re getting? If you have any other codes such as for the MAP sensor, EGR, or system lean/rich, diagnose those codes first as the conditions that trigger those codes can affect MAF performance. Same goes for any suspected vacuum leaks.
If that’s the only code, first check that the air intake tube between the MAF sensor and TB is sealed properly - clean any corrosion or build up that might affect the sealing surfaces between the tube and sensor/TB.
Have you cleaned the sensor at all? When was the last time you checked/replaced the air filter?
Keep in mind these are hot wire type MAF sensors - the sensing element has to be maintained at a certain temperature for accurate measurement. Debris of any kind, or oil film from a cleanable filter, that collects on the hot wire can affect its performance. With the code only setting after a long drive, the indication is the hot wire is not maintaining that temp.
With the key on, verify battery voltage at the pink wire. Ground is the black/white wire and grounds at G102 at the rear of the right cylinder head - there should be less than 0.5 ohms between the sensor connector and battery negative. If more than that, check resistance between the engine block and sensor connector. If still more than 0.5 ohms, there’s an issue with the wiring harness. Don’t forget to subtract the resistance of your meter leads to prevent misleading results.
If that’s the only code, first check that the air intake tube between the MAF sensor and TB is sealed properly - clean any corrosion or build up that might affect the sealing surfaces between the tube and sensor/TB.
Have you cleaned the sensor at all? When was the last time you checked/replaced the air filter?
Keep in mind these are hot wire type MAF sensors - the sensing element has to be maintained at a certain temperature for accurate measurement. Debris of any kind, or oil film from a cleanable filter, that collects on the hot wire can affect its performance. With the code only setting after a long drive, the indication is the hot wire is not maintaining that temp.
With the key on, verify battery voltage at the pink wire. Ground is the black/white wire and grounds at G102 at the rear of the right cylinder head - there should be less than 0.5 ohms between the sensor connector and battery negative. If more than that, check resistance between the engine block and sensor connector. If still more than 0.5 ohms, there’s an issue with the wiring harness. Don’t forget to subtract the resistance of your meter leads to prevent misleading results.
November 4th, 2020, 9:49 PM
#4
Is that the only code you’re getting? If you have any other codes such as for the MAP sensor, EGR, or system lean/rich, diagnose those codes first as the conditions that trigger those codes can affect MAF performance. Same goes for any suspected vacuum leaks.
If that’s the only code, first check that the air intake tube between the MAF sensor and TB is sealed properly - clean any corrosion or build up that might affect the sealing surfaces between the tube and sensor/TB.
Have you cleaned the sensor at all? When was the last time you checked/replaced the air filter?
Keep in mind these are hot wire type MAF sensors - the sensing element has to be maintained at a certain temperature for accurate measurement. Debris of any kind, or oil film from a cleanable filter, that collects on the hot wire can affect its performance. With the code only setting after a long drive, the indication is the hot wire is not maintaining that temp.
With the key on, verify battery voltage at the pink wire. Ground is the black/white wire and grounds at G102 at the rear of the right cylinder head - there should be less than 0.5 ohms between the sensor connector and battery negative. If more than that, check resistance between the engine block and sensor connector. If still more than 0.5 ohms, there’s an issue with the wiring harness. Don’t forget to subtract the resistance of your meter leads to prevent misleading results.
If that’s the only code, first check that the air intake tube between the MAF sensor and TB is sealed properly - clean any corrosion or build up that might affect the sealing surfaces between the tube and sensor/TB.
Have you cleaned the sensor at all? When was the last time you checked/replaced the air filter?
Keep in mind these are hot wire type MAF sensors - the sensing element has to be maintained at a certain temperature for accurate measurement. Debris of any kind, or oil film from a cleanable filter, that collects on the hot wire can affect its performance. With the code only setting after a long drive, the indication is the hot wire is not maintaining that temp.
With the key on, verify battery voltage at the pink wire. Ground is the black/white wire and grounds at G102 at the rear of the right cylinder head - there should be less than 0.5 ohms between the sensor connector and battery negative. If more than that, check resistance between the engine block and sensor connector. If still more than 0.5 ohms, there’s an issue with the wiring harness. Don’t forget to subtract the resistance of your meter leads to prevent misleading results.
Thanks for such a detailed troubleshooting guide.
What makes wonder about the fault is the fact that it looks only the change in altitude triggers it, and after a couple of drives around town, it goes away. Any thoughts about it?
November 4th, 2020, 9:55 PM
#5
as I said, the thing that the sensor measures -- air mass --- changes with altitude. So it could be going out of range or something after you climb. I would check all the things gumby suggested. He knows his stuff.
November 5th, 2020, 8:15 AM
#6
CF Veteran
What year is your van and what engine?
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