CEL won't go off!

[fangbosun]

Hi everybody! greetings from Oz!
I have a 1997 Vitara JLX 1.6 EFI 16V 5 sp manual. 195K kms, bought new.

I had the head replaced 2 months ago as the original one cracked.

In the last last few days the CEL has stayed on after turning the engine on. My mechanic read the codes and told me it needs a new MAF. He tried cleaning it but the light stays on. While I have great trust in him, the engine runs as well as it ever has? Is it unusual for the engine to run fine with a bad MAF? Is ignoring the CEL staying on a bad thing in these circumstances?

[Bex]

What market is your Trackick for...Oz?? If so, then you do not have the 'nag' switch (which is the service engine soon function, which will keep the CEL on until the little switch is turned off). Presumably your 1997 is still OBD1, however, which means that you don't need a mechanic to read the codes - you only need a paper clip to do this yourself. Info on how to do this is here:
Check Engine Light
Jump the codes, and advise exactly what code you are getting. Presumably its either a code 33 or 34. The MAF runs off of voltage, so you should check the wiring. With the key in the on position (but car not started) if you backprobe the black/blue wire at the MAF to ground (negative battery terminal) you should have battery voltage to it.. The black wire, using the same procedure, should have 0.5 volt or less - the gray/black wire is the output pin, and is 1.0-1.6v, with key on. With the car running, and warmed up so that the idle is 800 rpm, the output of the gray/black pin should be 1.7-2 volts, and should increase as you rev the engine up. Tons of info on the xxx site on how to test/clean this. Test the wiring as above, and report back what you get. Hopefully, it is only a wiring issue.

[fangbosun]

Sorry Bex, Oz is short for Australia!

Have checked the wires and the
1.black/blue is 12.6 V
2.black wire is .08 V
3. gray/black is .4 V and does not increase with higher revs.

Not sure if this indicates that the MAF is screwed?

Cheers

[xxx]

screwed maf DtC code 34 (dead maf)
if it fails my page, fsm and my tests are all there.

is yours a 57B or 58Bxx maf.??? the more is an air meter, VAF.
hard to find in some parts and crazy expensive new.

How to-test the induction Air meter.

[Bex]

Normally, this would indicate that the MAF is on its way out (or, actually, out, as in dead). That output voltage should rise as you are going faster. I don't know about success in getting a used one from breaker yards where you are, nor am I familiar with whether you have the same MAF system as in the US. This is an interesting read on how a MAF actually works, with a wiper arm inside that swings across a conducting strip - if you are truly bold, you may want to try the fix (or test) that is available here. The UK does have the Volumetric Air Flow meter, which is a bit different from the Mass Air Flow - I don't know which you have. However, it would appear that yours needs to be replaced, assuming that wiring is not the problem.
Air Flow Meter (AFM) Operation and Testing