Mass airflow sensor

A Jimny doesn't have a MAF sensor! (well a Gen3 doesn't)

It makes up the airflow by knowing the throttle position, engine speed, inlet air temperature and manifold pressure recorded by the MAP sensor.

Pull the MAP sensor and make sure that the passageway into the manifold is clear, along with the hole in the MAP sensor.

If you can read live data on the MAP sensor ignition on, engine stopped, it should read 100 ish kPa, if it reads zero, then it is shorted to ground, 126 kPa shorted to 5V.

You could try removing it and put a tube on the port and suck on it, you should get the indicated pressure to go down.
 

facade wrote:

A Jimny doesn't have a MAF sensor! (well a Gen3 doesn't)

It makes up the airflow by knowing the throttle position, engine speed, inlet air temperature and manifold pressure recorded by the MAP sensor.

Pull the MAP sensor and make sure that the passageway into the manifold is clear, along with the hole in the MAP sensor.

If you can read live data on the MAP sensor ignition on, engine stopped, it should read 100 ish kPa, if it reads zero, then it is shorted to ground, 126 kPa shorted to 5V.

You could try removing it and put a tube on the port and suck on it, you should get the indicated pressure to go down.


 

Umm... Mine does. I don't think I've seen one without one. (Stand to be corrected on that). the air temp and air flow are measured at the same sensor. MAP Sensor only measures pressure (which is actually vacuum in a jimny) as far as I'm aware. 
And if its showing on his OBD readout then it must have one installed or it would have thought it would show N/A or no data or not even appear at all. 
Located right after the air filter in the plastic air intake piping. 
Which occurs to me as I'm typing... have you checked the airbox and filter that its not blocked? there is also a short plenum thingy above the wheel well that feeds the airbox. (assuming no snorkel). if its been unused for a while a rodent could have built a nest in there - pretty long shot though. 

What engine do you have?
The Gen3 M13 and g13 don't have MAF sensors, only MAP.

I just examined my Gen4 K15 engine, no MAF sensor. The IAT sensor is in the short rubber pipe from the air cleaner to the throttle body and what must be a MAP sensor is on top of the cast pipe leading from the throttle body to the plastic banana manifold, right next to the throttle body.

The air flow is just made up calculated by the ECU from the other data. It is close enough, then when it goes closed loop it uses the primary oxygen sensor to trim the fuelling.

facade wrote:

The Gen3 M13 and g13 don't have MAF sensors, only MAP.


 

No personal experience with them, but looking at the FSM, some of the G3s possibly the ones with VVT, do have a MAF sensor.



The expected flow rate "at specified idle speed with no load after warming up" is 1~4 g/s

fordem wrote:

facade wrote:

The Gen3 M13 and g13 don't have MAF sensors, only MAP.



 

No personal experience with them, but looking at the FSM, some of the G3s possibly the ones with VVT, do have a MAF sensor.

The expected flow rate "at specified idle speed with no load after warming up" is 1~4 g/s

Yep M13A VVT Engine is what I have.
All Jimnys (at least in NZ) that I have seen after 2005ish with a 1.3 are VVT. 
OP has same year as mine so will have VVT and a MAF sensor I presume. 

I stand corrected, so they do! 

I had checked the 99501_81A10_01E manual, but didn't spot that I was looking at 6.1 for non-vvt rather than 6.3 for VVT engines.

My Gen3 was M13 non-vvt.

I wonder why they went to MAF, and then back to MAP for the Gen4.......