Succinct

Took my '03 to dealer today to diagnose this warn start stall problem that began right after they re-progammed my ECM per the NTB-003 TSB. The symptom was that the car would stall 1 or 2 seconds after starting it when warmed up (like when trying to leave after a quick stop at the store). There was NO SES light and engine power was very strong in general otherwise.

Verdict? $840!! Dealer SA says I need a new “Air Flow Meter”, which is $600, plus the $240 labor & misc. He insists the air flow meter is not the same thing as the MAF, which I can get at getcoolparts.com for $160. I tried calling Dave B but he’s at lunch.

Dealer SA said the mechanic spent over an hour and a half trying to diagnose the problem because it was throwing no codes. They finally found that the “air flow meter” was reading 1.9 volts at base idle and said it should be at more like 0.10 to 0.15V, so it was really out of range.

What to do? Is the dealer trying to fleece me? WTF is the “air flow meter”, and where is it relative to the throttle body? HEEEEELLLLLLP!!!!

P. Samson

It's semantics. The Air Flow Meter is the whole MAF "assembly" which includes the sensor and airflow tube/housing in which the sensor is mounted. I have not yet checked the TSB but on the '03 I believe you should only have to buy the sensor itself. I just ran through the TSBs. On your '03 the ECM P/N was the driver for the ECM reprogram (at least that is why I guess the dealer did the reprogram in theory). The '03 MAF ASSEMBLY P/Ns can be different but I believe you should be able to change out the MAF Sensor only. Some early '02s did require the replacement of the Air Flow Meter Assembly but that is not applicable to your car. The dealer may be misreading the TSB or ?? I don't know what FSM the dealer is supposedly looking at, but the one I'm looking at has the warm no load idle voltage spec. (as read by Consult ll) of 1.1 - 1.5V. and at 2500 RPM it should be 1.7 - 2.4V. Your 1.9 volts is not that far out, and that could be because of a slightly higher idle for example.

Succinct

OK, so I talked to the Tech who did the work ("good guy", BTW) and here's the outcome:

He says it's the MAF sensor ("air flow meter" is the same thing), based on the fact he was reading 1.9V at base idle in lieu of the 1.5V it should be (thanks P. Samson). He said he cannot "rule out" the throttle actuator/position sensor (on the throttle body), but he couldn't find anything wrong with it, and he said when those go bad it usually kills the whole engine. Plus he sez he's never seen an actuator go bad on a 5.5G Maxima (but sees 'em go bad all the time in Muranos - word).

I noted how a car's power usually drops when a MAF goes bad and asked him why my car was still running VERY strong, and he didn't have much of an answer, other than he found those readings outside of range, and MAFs go bad on Maximas all the time. Sounds like there just isn't much other evidence.

Per Dave B's prompt, I also asked the tech about whether an idle re-learn was done after the TSB and he confirmed that he did that.

Interestingly, he said he could not duplicate my stall problem in the shop, even though it had become less intermittent and more consistent in happening to me lately.

Oh well, all they charged me for was their basic diagnostic fee of $46.

SO HERE'S WHAT I DID: I ordered a new G5.0 MAF from Dave B for $83, and will install it this weekend, swapping out the IAT. The Gen 5.5 maf was something like $360 from Dave, and $83 was still cheaper than getcoolparts.com for the Gen5.5 MAF from them ($160). Beats the $840 the dealer wanted.

ONE LAST QUESTION: Keeping in mind I've had the TSB (NTB-23003) done, do I need to take it back to the dealer after installing the new MAF? The tech I spoke with said I'd need to. Nissan tech guys, please respond if you can, thanks!