Have been chasing this code for almost a friggin year now. In the process of trying to bring this old girl back to new like condition, many dollars, as well as hours of labor & frustration. For the most part, an enjoyable, as well as a very successful project. This 101 code is driving my closer to the edge of sanity every step i take. Vacuum leak is what this usually indicates. If no leak can be found, it is usually the intake manifold gaskets, with the eight between the top & bottom sections as well. Is anybody having trouble finding acceptable mass air flow sensors? My cat spits them all out like a hair ball, the trims are great after you give it some fuel. And running down the highway they are all around 0 to, + or - 5,on all four. But changing throttle position, makes them jump all over till you resume, then they settle right back down. Have been told an awful lot of the sensors out there are not acceptable to our sensitive cats. There are at least two grades of them. Much like you can use fuel line for coolant lines, but not coolant lines for your fuel.Our sensors can always be used on the Toyotas, but many of their sensors do not work well for us. Has anyone else had this issue, & do we need to pay for the Jaguar Dealer M A F sensor to get things to settle down?

 

Hot engine, parked, at idle. What are they? Should be near 0.

 

They are,0 to + or - 5 for the most part, when running. But at idle they are too high, & all over when you let off the gas. Like it's hunting, drive away things drop back to normal, & all's well, milage in town,in the twenty's, high twenty's on the highway. Car runs great, & the tailpipe E check test's results, are extremely low.

 

So figure out why and fix it.

 

Well boys & girls was informed by a supposedly knowledgeable exotic car wrench that he has had nothing but bad luck with other than Jaguar mass air flow sensors. They are not as accurate in their calibration as the Jaguar sensors are, so the light is going to be tripped. Bit the bullet and bought a new one made in Spain from the dealer, OUCH they sure are proud of them. Sure hope this solves my problem. If not, any other information would be much appreciated, as i'm at a loss at this point to know what to do.

 

What now??? Trims are much improved, bounce around a lot less, seem lower for the MOST part, milage keeps creeping up, but the dreaded light keeps coming back on. Replaced all ten intake manifold gaskets, P C V valve Jaguar, as well as Jaguar M A F sensor, air filter, everything looks to be in order what else could it be???? The computer??? W T F???

 

After plenty of driving so it has relearnt, is it still only P0101? If so, look up all the causes in jag's JTIS and work through them.

 

Have heard about a hard reset for the car, what exactly is it, how it is done, & could this help?

 

No.

 

All right. Help me baseline my understanding of this.

You've installed Jaguar OEM sensor and have cleared the code after install by this point, correct?
The code keeps coming back, correct?
Parts fired from the parts cannon are all the intake manifold gaskets, the MAF sensor, and air filters, correct?
Do you have a factory service manual, and have you followed any sort of diagnostic flow chart pertaining to the 101 code?

 

Well after the hard reset, & a few hundred miles, light finally went out on it's own. After some more miles, the pending PO101 code went away. Now when the PO1000 code clears after a few more cycles all should be well, i hope. Sure appreciate everyone's help sorting this out, been a real learning experience.

 

Today the DREADED light and code returned. Trims are still a bit erratic, when you let off the throttle but not as bad as b4, with the non jag sensor. When your traveling along the trims are kept at almost 0, the whole time, short as well as long.My understanding is a diaphragm is combined with an electric sensor to talk to the M A F sensor, to control the amount of fuel to the injectors. Could the M A P sensor be bad?Don't want to replace it unless it needs it, but 91,000+ miles, the diaphragm could be about shot. Car is from the Carolina's, it's pretty hot down there, and rubber gets old after a time, just like us.