TESTING that pesky AIR METER on 16 valve engines, USA uses -58B meters.
NO 57B data, for EU Type 2 engines.
what does -57B or -57B mean, that is part number stamped on the side of the MAF
All testing and data on this page are
13800-58B00 (USA only) See Realities here.

News flash see China Clone MAF, fully rev. engineered and repaired.

I made this crude excel plot. ( Excel need, if not see jpg echo

MASS AIR FLOW  Meter , MAF or LuftMassenMesser (German)

Or  the  Air flow  Sensor / meter, AFS or AFM .  (Luft Messer) and VAF(V=Vane)

There are 2 kinds  of the meter the  MASS  or the Volume Air flow.

NEVER TOUCH ANY HOT WIRE element with HANDS or tools, only spray it with CRC MAF cleaner, at over 6-12 inches away.
This page is not for Force Induction guys, or Turbo wana be's  ,it is only to test for good and bad FAM.
My guess, is this MAF goes non linear badly after 100 grams/second, and would be a bad choice for any forced induction usage, nor do I know when the ECU MAF INTERNAL TABLE END'S.
The ECU needs this meter, to know the quantity of air entering the engine at all times, either as a mass (weight) or as a volume (cubic feet?)
This live data is needed to calculate the  injection needs of the engine. (besides other factors)
I will make no attempts on this page to teach you, the difference from mass and air flow but the wikipedia does that so well.
This page is my personal log for collecting facts and data and how to test this simple  device.  There is no content warranty here, use it or leave it.
The technician only needs and whan's to know, is it good or is it bad.?
Some MAF's actually do a Hot wire, coke burn off session, each power up cycle. We think this MAF does not  do that step each key on., the 58B  MAF.
The pure mechanical Air meter , Air flow meter , the vane can stick or the Pot. Inside can get flat spots.  (a nasty thing that is...)
The same is true for the 57B, it can stick or have flat spots at certain air flows.
The 58B Electronic MAF,  is a far superior product, than any funky vane sensor. ( a toy  like device)
The MAF output is logarithmic and needs ECU table to convert this log data to linear grams per second, so it can calculate how much fuel to add the THIS air flow.

The Air Flow meter on many cars, is a simple flapper vane and a potentiometer. Crude as can be.(but effective )

The Suzuki outside the  USA uses a spring loaded cone Air Flow meter.  seen below.

Our USA meter is a true MAF. The MAF uses a HOT wire for measure AIR MASS FLOW.

The MASS measurement is improved by measuring air temperature.



You might be here for gross power loss, or DTC code 34 or P0101- 103.
The ECU WILL drop to FAILSAFE mode when this happens and get horrible MPG, due to ECU MAF Mimmic mode.

 Hot link to my Simulator.

USA Applications:

1.6L MFI (MPI) Engine  (multipoint fuel injected engines, 1.6L and 1.8L and others)

Suzuki Sidekicks and Geo Trackers. 92-98'.  (same Suzuki P/N sensor all years 13800-58B00 USA)
The Toilet plunger MAF has a different part number.

My way:  ( no crawling on belly or back , not yet) 13800-58B00

  1. Get any voltmeter, analog or digital , I dont care so long as it is over 10,000 (10k) ohms per volt resistance or  greater (RTM).
  2. Set the meter to 20vdc range ,fixed is best , cheaper meter are fix and this is best of novices.  Put meter leads in the 2 holes for voltage, not current.
  3. Connect the minus lead of the meter to the minus term (black) of the battery .
  4. We then back probe (no disconnections)  and power on the KEY of the car, not started.
  5. We insert the read  probe into ( use a leather sewing needle if  in a pinch) in to the Blue-black wire of actual MAF. Drawing 1 see it?
  6. It must read 12.6v or battery voltage.
  7. Do the same to the Black wire, it must read 0.5v or LESS.
  8. If the above passes muster ( if not correct wiring or test ECU, using factory FSM way below.
  9. Next move the probe to the output pin. Gray-black wire,  the voltage key on, no start is 1.0–1.6 volts , if not MAF may be bad.
  10. Start car, this pin must be 1.7–2.0 volts. at 800 RPM, if not MAF is bad, or RPM is wrong.
  11. The MAF measure air flow, so race the motor and the MAF can go and reach 4.75v worse case up a tall hill , wide open throttle but in the drive way it will rising in direct linear proportions to  Load and a less extent to RPM and can reach  4volts in the drive way if you use the automatic tranny as a load in drive. Just racing motor in neutral one my get 3v.
  12. If the MAF is dead, then it is. 
  13. The Chicken and egg thing, is that if the MAF is dead or weak? , you can't make any  power and therefor can not do the test for load. The same is true if the motor is bad and weak , you can not test the MAF ,so you must prove the motor is good before condeming the MAF or test the MAF on another car.  They are very expensive $800 new.  but you can do test 1 to12. for sure. Up to 3v , in all cases.

This concludes my MAF test on car.

FAST RULE LIST 1a: Output.Gray-black wire (running unless stated other wise)  all the way to fail.  13800-58B00
  • If MAF output  is stuck at 12vdc  so it is blow out.
  • If the MAFoutput  is stuck over 1.7–2.0 volts AT 800 RPM, then the MAF is bad ,but the RPM must be 800.
  • If the MAF output will not advance above 2v while raising the RPM then it is dead.
  • If the MAF output is stuck at 5v, or 4.75 volt are near maximum , all the time , it is bad.
  • If the MAFoutput  is suck below 1.0 Key at key on , not started ,it is bad.
  • If the MAF ground pin is not 0.5v or  lower , then your ground is bad, repair wires.
  • if the MAF power pin does not read the same as the battery voltage 12.6v , then you have a power failure. The ECU uses this same power.

The Factory way: 13800-58B00
Below is  FSM  excerpts  , with my  red word comments.  ( which to me is the hardway to do it).



NOTE: It is necessary to use a Digital Voltmeter (DVM) set to the voltmeter function, or a

high-impedance (10 ,000 ohms / volts minimum) voltmeter, otherwise erroneous readings will occur.

Any DMM,DVM will work ,this warning is for antique tools.  Any DSO will work or any scope.


1.  Use the DVM to measure the battery voltage (positive DVM lead to the positive battery terminal, and

the negative DVM lead to the negative battery terminal). Note the battery voltage.

2a: Jump to the end to do my Fast Test of the MAF , right at the sensor itself. (last paragraph)

2b.  Remove and position the ECM/ECU along with its bracket, relays, fuse panel and wiring harness on the floor

of the vehicle. Re-attach the wiring harness connectors to the ECM. This is done to allow access to the unit during testing.

3.  Disengage the wiring harness connector from the MAF sensor.

4.  Attach the positive lead of the DVM to the B+ terminal (positive battery voltage) of the MAF sensor wiring harness side connector. Connect the negative DVM lead to a good engine ground.  B+  means Battery  Voltage+.

Fig. 1:
UnPlug the wiring harness connector from the MAF sensor, then attach a DVM (engage the voltmeter function) to the B+ terminal (blue-blk) of the sensor connector and  a good metal body ground.


5.  Turn the ignition switch ON and ensure that the voltage at the connector is the same as the battery

voltage noted earlier. If the voltage is not the same, inspect the wiring harness for an open or short circuit.

6.  Turn the ignition switch OFF, then reattach the wiring harness connector to the MAF sensor connector.

7.  Backprobe one of the DVM leads to ECM terminal B8 , and the other DVM lead to a good chassis

ground. Turn the ignition switch ON and read the voltage of terminal B8. The voltage observed should be 1.0–1.6 volts.

8.  Start the engine and once again check the voltage at terminal E32–9. The voltage should be lower than

5 volts (exact specification is 1.7–2.0 volts) at idle and gradually rise as you increase engine speed

(rpm). It might rise to 3 to 4 or 5vdc if you test at full throttle and under heavy load.

If you have an automatic , do so in Drive, and floor gas pedal (brakes locked)

With a manual tranny , you need to be more creative.  (wires dangling from fire wall to passenger with meter)


9.  If the voltage did not react as described, there is a problem in the wiring harness, the connectors, the

MAF sensor or the ECM.


THE 1996 and newer (USA)  OBD2  TEST WAY: With a real SCAN TOOL        13800-58B00                                                                    

NOTE: To test the MAF sensor, a diagnostic scan tool is possible for  1996 and newer.


1.  Attach a scan tool to the Data Link Connector (DLC) with the ignition switch OFF.

2.  Start the engine and allow it to reach normal operating temperature.

3.  Using the scan tool, check the values displayed for "MASS AIR FLOW RATE." The airflow rate should

be 0.20–0.53 lb. per minute (1.5–4.0 grams per second) at idle, and 0.66–1.32 lbs. per minute (5.0–10.0

grams per second) at 2,500 rpm.


A.  If the values displayed by the scan tool do not match those specified, the MAF sensor is faulty;

replace the throttle body with a new one.

B.  If the values displayed by your scan tool match those specified, the problem is an intermittent
     fault in the circuit or a faulty ECM.

All red words are mine, black is OEM. Factory and blue are accents, by me.
end FSM excerpt and commentary:

The MAF can be data logged with any scan tool like this.

Better plot with TPS ,throttle logs.


ONLY a Factory TECH1 or 2 scan tool, can read the live flow rates of the MAF 92-95’.  Starting in 1996 OBD2  scan  tools  can  plot this sensor.

The MAF just measures air flow into the engine intake and the ECU uses this reading to mix perfect fuel to air ratios at all times.

The sensor is non linear and the ECU, has a table inside to correct this to real air flow.

The Grams per second, can hit 60g/sec, under full load. (mine hits 55g)  As measured by a forum member with a 97’ 1.6L Sidekick JLX.

This was obtained, at wide open throttle during  the 1 > 2 shift point , up a tall hill.  ( i get max in  3rd gear  WOT  up hill )

If you have a V6 the numbers will be higher by 30% or so. Under heavy load.

The 10g/sec is under no load  shown in the  FSM is only a  basic crude test.   You need to test it , under load.

The more load , the more air flow.  Max air flow, max load  equals max horse power.  Mostly.

This data is hard to obtain.  But here it is, thanks my OBD2 scan tool. (at end of this doc.)

Addendum:    See  here for  older or newer  ECU  pin. at  13800-58B00

The MAF sensor must be tested in the car connected because testing it on a bench requires a huge source of air.

I don’t think  a vacuum cleaner can do that. BUT A  LEAF BLOWER AND DUCT  TAPE?

FAST TEST ?, just connect your meter at the sensor using back probing with a needle.


MAF pin Out list: (typ. 92-95’)  USA ! models.

 1--- Blue/black ---- Main +12vdc  power

 2--- Gray/black --- MAF output signal  1 to 5v , proportional  to Air flow.   B8

 3--- Black ---------- Ground.


 Click here to see schematic of ECU Pins: , save it , zoom it, it is High Resolution !


Using and engine that has and EFI that does not have mimic or failsafe  mode, like the Old  1975+Bosch L-Jetronics systems.
If the vane jams shut , the car will not run,  VAF  output zero !
So how can you test the VAF/MAF if  you can't start the engine,  the classic chicken and the egg, joke . (see vacuum cleaner above)

Fast forward to 1992 (USA) and Suzuki has a ECU that has fail safe and mimic modes.
This car starts, and will mimic the dead MAF/VAF and run ,  and run  rich.
It throws a DTC code and the MAF/VAF is dead, sitting at say 0v. 
codes:  pre96' "33/34 code, 96'+ P0101-1023"
But some MAF's will be weak. No DTC code, This is where Mr. Warren comes in with the MAF/VAF
simulator box. 

A real test:    13800-58B00
The only other way, is to use a Leaf Blower attached to the MAF off car and then monitor the output
with power applied and spinning up the blower.
Another good application of duct tape (blower to MAF)

Wire colors:
You may have up to 5 pins on some models 99+, MAF and IAT pins. (out side USA),
but our USA MAF's are 3 pin MAF's 92-98'
Pin colors:
Power 12vdc ,  Blue/blk (or Blk/org)
Ground , Black
Signal out to ECU,  Gray/black

Live running test, connected in parallel to car wiring:
I have been known to run wires from my MAF to the cab of the vehicle and then take readings while driving. (passenger helps me)
Using back probing of the connector.

The Mimic mode trick test:  Don't be fooled if this happens,  The car will still run with a dead MAF,  like crap for sure.
One can then connect  the MAF  as below , and test the MAF  by itself , on car,  if the ECU has a good mimic mode method.
Most ECU's can mimic a dead MAF  using  TPS, RPM,Speed and Load tables stored in memory.  ( its not fancy , and you may have power loss)
But, you can test the MAF using the below method.  Volt meter attached to TP , below. and meter ground to minus pin , BLACK.

My MAF simulator (  this can save you $800)  .  ( A special thanks to Mr. Mark Warren at Motor magizine for my idea)
Don't do this if you have a spare MAF just laying around.....
Connect and run 3 wires from the MAF harness in engine bay connector 1 ,2 and 3 ( see color code in drawing 1 below)
Next, have a  passenger act as a MAF ,  guessing at air flow, when the engine bogs,,  turn the knob Clock wise to ADD fuel.
If the simulator and the passenger helper can easily correct the bog condition , your MAF is probably dead or weak.
It is that simple.

SEE my schematic of this SIMULATOR.
Put a lable on the knob , marked Air flow and an arrow CW for max.

The MAF enjoys a special PAIN, in the back side, for mechanics.
This is the law of the Chicken and Egg, as in What came first.
The Motor can not make power with a dead maf (or weak) and  the MAF can not be tested unless motor makes power ( motor can't SUCK)
The simulator solves this problem  (thanks to Mr. Warren )
Success with this simulator proves that higher MAF outputs , results in proper fuel injection rates.

This test is never run until the fuel pressure is at specification, (near 30psi) and a good motor.  (all other things checked out first, then attack the MAF)

Bench testing my USA MAF ( DYI flow bench ): 13800-58B00
The Leaf Blower / Vacuum cleaner test:  Air meter  or Mass Air Flow SENSOR.
  ( I put on my tin foil hat  and have at it .)  This is non scientic in that I have no data on my shop vac. (flow data)

This, is the Leaf  Blower  (vacuum cleaner? shop vacuum is far safe for MAP) )connected to the "A" side below , the other end vented to the atmosphere.
Then apply 12vdc  via battery or shop 12vdc power pack supply, as shown.
Then monitor the TestPpoint  pin below for 1 to 4.5vdc output , as you increase the blowers speed. MAF output is Gray/black to ECU.
A NEW MAF is  $900 in the USA, this one factcan motivate one.   This is a GO, NOGO test.
This test , proves the MAF is dead.  A Dead MAF (or air meter)
Operating , on the acutal car, this MAF will cause the ECU , to drop to MAF Failsafe  mode and the ECU mimics this device.
So, this test is the ACID test. 
If you have  meter with a diode test mode , you will see a Diode Anode + on pins 1 to 3 and 2 to 3 (cathodes) see equiv. link.
See this equivalent circuit, here.. All pins meassure over 2 meg ohms, (diode mode off)

DRAWING 1: ( X equals a cut, do not do this to car harness this is a bench set up , with a removed harness for a wrecker yard, car ) 
Theory of a poor mans flow bench below :

In mech, terms the above,  the out put will vary from about 1v to 4vdc as you drive fast , wideopen throttle , up hill, at the 1>2 shift, is max AIR flow.
G/s = grams per second ( yes, air does have mass !)
The graphic above shows "X" volts for this test, and x = 1.4vdc vacuum off, and 3.0vdc vacuum on.  "ShopVac10, 7.8Amp"  {note1}

The FSM does not show the pin number locations, so watch colors carefully.
DTC Low fails below 0.64vdc
DTC high fails if output sticks above 4.9vdc.
The input impedance of the ECU on pn B6 (maf)  is 1000 ohms, 1K (and is a precision termination resistor inside the ECU !)

End tin foil hat:   ( wish I hadn't sold my Variac )

OBD logging my MAF 1996 in my  Tracker, data logging and testing by me:  13800-58B00
USING my OBD2 Palmer Scan tool data log feature, and Excel plots.

I get a max of 55 grams/sec. of air, out of my MAF.   The Proof is below. THE AIR IS MEASURED IN GRAMS. (RATE)
These plots are from live data taken from any scan tool.  (very easy to do)  The method varies by you  tools, design. All good tools can log data/
Graph 1:

Graph 2:

Graph 3:

I found a bad thermostat , see it stuck at 160F.  {it  was grossly slow to regulate and then at the right point} The STAT is now, in the trash.

The Best for last , click here to see a 1997' dynamic test of the MAF sensor.


Not the dealer. they want $1019 now (2014)  What a rip off.?  a 20% price rise in 4 years. too.
Not fleabay used, they want $100 for used ones, with no returns dead.
Not fleabay China clones, because they are CRAP.
Best price,  is rockauto.com come, no better price or selection !!  google em.
Best USA maker (its rebuilt by pro's) is CARDONE.

Their Ebay store:

Example Ebay listing for above store.

MAF PHOTO's   (aka: THE AIR METER)  The USA MASS AIR FLOW sensor.:  SUZUKI  p/n 13800-58B00
Below, is the common HOT wire  type,see it?, clean that gently from 6 inches away with MAF cleaner.  (carb cleaner in a PINCH) 100% Electronic.
Do not remove this screen , it is not a screen it is a laminar flow device,  it straightens the air so the hot wire can take readings accurately , don't molest the MAF.

NON USA APPLICATIONS:  Suzuki  P/N: 13800-57B00 , Not used in USA.  The other  58B AIR METER is used in USA !
This is NOT A MAF.! its and air flow meter. (volume) it is a VAF seen below.
This is theSUZUKI EPC  list for this  part.

This is the UK type 2 ECU , that this device connects to and the CO tuning resistors.

I believe this below device, works in a  way simular to this VAF 
Below: THE cone type AIR Flow METER.    This device measures VOLUME of the air and never MASS flow!
It looks like a Toilet plunger to the average mechanic, that has seen vast numbers of  VAF sensors' on many cars. (VW back to 1975)
I have no pin-out data on this device.  (no DATA PERIOD !)
"No cleaning  is  possible", are the reports I get,  From Australia or Europe and other EU owners. (but I'd try to, I'd attemp to get the sliders clean)
I am told this part is very hard to find. and if possible is insanely expensive new.  $1000  at Suzuki acutal.
This device measures,  Air flow , not air mass.
The technician, does not  care too  much about  these EXACT data. (VAF/MAF)  and only that it works at all speeds and loads. 
There are no dead accurate data from Suzuki on this VAF.  Grams/sec to voltage tables, published,  (sad huh ?)
No USA  books exist showing the VAF  flow/voltage relationships, for this device only crude tests. like shown in the factory way above.
I have no tests data for this device below, In fact, they are impossible to find here , in the U.S.A.
If you have one, get the FSM for your cars country or market code, (match that , and you will get the facts)
I show this  photo, for identification purposes only, just in case you discover one.

I think the below is 100% mechancical .  ( and a variable resistor)   The below may have an Air Temp; sensor too. (extra pins !) and  IAT?.
The 57B in all its glory.

The ECU is custom  tuned (tables) to match , which type of air meter is used, 57B or 58B !

I deleted my hacking seection and added this new section called RELALITES.
  • Most used MAFs (air meters) that are 22 or more near years old are in fact dead, finding good used meters is like finding gold coins in the pants pockets of cloths at the fleamarket.!
  • Most China Clones of this part are pure CRAP.  (junk, trash and a danger to a good ECU)
  • The ECU never lies to you , when bad code 34 DTC (P0101 to 3) is thrown the MAF is bad, or the wires cut. Do the testing above, and prove all that easy.
  • New  dealer MAFs are $1019 (2014 price)
  • Cardone makes the best rebuilt in the USA. and is sold in almost every AUTO  store in town here..
  • The MAF is a non linear device  and the ECU has tables that turn that live data in to true, grams per second data,  So you  can't use the wrong MAF.
  • Yes, dirty MAF hot wires, can show weak air flows, and lean fuel mixtures while accelerating,  clean it with CRC MAF cleaner with spray nozzle at 12" away from the guts of the MAF.
  • If you own a 57B above, cleaning its   sliders inside, may make it start working. It has no hot wire. (it's just a POT or variable resistor type, simular to a vane type VAF)
  • If the VAF/MAF is dead and puking DTCs  for MAF ,the ECU goes to Failsafe mode, and the ECU then mimics your dead MAF and the engine will run like crap.
  • Your engine will run rich, spark retared, wasted fuel, horrid MPG, limited RPM and loss of idle controls.  (fail safe mode does all that) be heck, it runs and can get you to any parts counter.
  • The side effects of above line, is fouled spark plugs and the burned up and or melted CATALYST converter.
  • If mine was bad?,  a rebuilt CARDONE would be stuffed in. Fast.

All data presented on the page is data supplied by Suzuki  (or me)
The one exception is in my Bench testing section above.{note1} Vacuum test data.

More data: (calcs, not factory spec.) 
100% VE AIRFLOW (scfm) = DISPLACEMENT (ci) x RPM / 3456    (at standard temp an pressures)  97 CI times 5000 RPM div. by, 3456.
97x5000/3456 = 140 scfm. That the max air any 1.6L engine can flow.
Our engine will be less.  (note the VE is 100% and not achievable)  (VE= Volumetric Efficiency , at best   about 95%)

A Parting shot:
I never plotted FULLY the Suzuki MAF (sadly) on the high end, to see where it goes grossly nonlinear, and where it saturates,  My guess, is it ends at 4.5v just like the Ford Probe above.
Note carefully, that the top end is very bad, so using forced induction in the 4 to 4.5v range would be very bad.  The flow there, is IN-DETERMINANT.
Other MAFS, like the Toraus V8 MAF is horrible at idle and very good above that to the top.  ( so do your testing or get real data sheets on your substituted Air meter.)
The Suzuki maf ,is so good it used at idle. Other cars it's not.
On some newer cars, the MAP is used at idle, then when the MAF starts working right, it comes on line.  (Greg Banish covers this in his new book at Amazon)
Most sad of all , most MFG, don't bother to put the plot , in the FSM.   Very sad that.
The MAF , goes to maximum in the Suzuki at 98ft./lbs, 4000RPM , max load.  1.6L MPI  up a tall hill, using all engine power. at 4000 RPM.
If the MAF is weak , you don;'t get the 98 fl/.lbs. you get less.  This speaks volumes about a thing, called the chicken and the egg. !
The ECU can not detect a weak MAF, only the seat of the pants. (if bad, enough  the ECU, might throw lean  DTC codes,at wide open throttle, maybe......)

Rev 7   5-26-2014,  edits for turbo guys.... (may be more later as others try to do force induction and do more testing)

Jargon confusing?  Sure it is, but I only use 25 or so out of 3000 SAE terms.