Well... round 4 of the MAF issues has started.

After driving the car for almost 6 months to the day, the MAF died (again). Currently, I'm blaming the ECU for this. Here's the deal:

My car was manufactured in 10/2001. The first run of ECUs for the VQ35 was supposedly in 09/2001 (to be installed in 10/2001 cars). So basically... I've got one of the first VQ35 ECUs. I've had several updates and TSBs done to it over the warranty period, including re-flashing for the O2 and MAF TSBs. But yet here I am 2 years later... stuck with my 4th dead MAF and still throwing O2 sensor codes. I've replaced/inspected/cleaned/etc everything I know how to... and had the dealer do the ones that I didn't know how to do.

Recently, I asked the dealer to re-flash (for the 3rd time) the ECU for the O2 sensor TSB. When the went to load up the flash, the program said that the ECU didn't qualify for the flash (as it had been flashed before). They attempted to load the MAF flash as well, but the same error occured.

I asked if they had an old image of the ECU that they could flash to it, and then flash the updates to that image. It appears that my stock image (at time of delivery) is unavailable.

Seeing how it is that there are no possibilities of getting any updates for the ECU, nor reverting to an older version and updating that one, I decided to take things into my own hands. So here's my plan to fix it:

I ordered from a salvage yard 2 things. An ECU from a 11/2001 production 2002 6-speed SE base model (with leather), as well as the MAF from the same car. The car had been involved in a roll-over, but the parts were purchased with a full warranty and return policy, in case they don't work correctly.

Once the new ECU and MAF arrive, I will drive my car down to the local dealer on the new MAF and my current ECU. I will then, in the dealer's lot, change out the ECU to the new ECU. I will have them re-flash my keys to the new ECU. I will test out the ECU to verify that there are no problems with it.

Once the ECU is confirmed good, both ECUs will be sent to Technosquare. Technosquare will copy my current ECU over to the new ECU (as a duplicate). They will then upgrade my current ECU to the performance flash that they normally do. Then they will send both ECUs back to me.

Once I recieve both ECUs back, I will install the performance version into the car and start the learning process. After the first 100 miles, I will then head to a local dyno shop for dynoing.

Then, and only then, will the true side-by-side comparison take place for the Technosquare update. Same car, same dyno, same day, same weather, same mods, only a different ECU. I will also make comparisons between the ECUs with and without the Greddy E-Manage tuning. This way, we can eliminate the E-Manage as a variable.

I am hoping that this will also solve the SES/MIL lights on my car for good - at least on the performance ECU.

 

Your ECU is not causing your MAF failures.

 

From what I understand, the ECU sends an output current to the MAF... if the ECU sends too much current to the MAF due to a faulty output driver or a screwy ECU, the MAF could potentially be damaged... The more air flow across the MAF, the greater the temp drop on the hot wire in the MAF... as the temp drop on that wire increases, the ECU increases the output current... if the current being sourced by the ECU is too great or has bad transient behavior, the MAF could fry... especially the fragile ones on the 2k2/2k3.

 

Not to be defensive or anything, but exactly how would you know that? I have spent many many hours and days reading, researching, testing, etc the MAF sensors for the 2002-2003 Maxima. When I blew the sensor this weekend, I immediately reset the ECU and replaced the MAF with a borrowed one from E55AMG2's car. The car drove fine. So how is it that the car blew a MAF that morning, yet ran fine that afternoon? Resetting the ECU only erased all the (bad) settings that the ECU learned, so as not to damage E55AMG2's MAF.

Take my word on this... there's nothing else causing the sensors to go bad. The intake hasn't changed... the air hasn't changed... the filter hasn't changed... nothing. So there's nothing else that would cause the sensor to fail, other than the components in which are connected to it. And the MAF sensor only attaches to the ECU. 4 out of 5 wires go from the MAF directly to the ECU... and the other one goes to an engine ground screw.

I've located the Bosch and JECS part numbers for the sensor itself. I'm trying to locate dealers who can sell the sensor itself for less than the DaveB price of $390+. But for now, http://www.car-part.com/ has saved the day with a $150 sensor.

 

I thought just the sensor was like $80?

 

I think that was for the 3.0 engines....and I need to get a spare, apparently....all this MAF failure makes me want to take the Frankencar off so I don't have to worry as much...for the umpteenth time...does anyone have the SPECIFIC PART NUMBER for the MAF sensor (not the whole assembly) so I can go to Nissan and just buy one.

 

I'm pretty sure DaveB sells the sensor only for just about that. The $390+ number is for the whole unit housing and all. Yes this is also for 3.5 cars not just 3.0

 

Here's where i'm wondering... my 2k2 was made even earlier than yours. I don't remember exactly but it's approximately 7/2001.

I'm at 37k right now and no MAF issues. They did replace my MAF and flashed my ECU per the TSB right before i expired on my 36k warranty. (My service rep suggested it even though i didn't think i needed it).

 

Mine is a 1/02 build, 14k on the car.
No TSB's done to the car.
No trips back to the dealer at all.
No MAF problems.
I've got a Frank/$tillen Pop combo on for 12k+.

 

So the MAF on the 2k/2k1 is less likely to blow compared to the 2k2/3 ones?

 

Studman,

What color card did they have in the consult II when they said it could not be updated? If they couldn't flash it, or find you a suitable ROM revision, doesn't that warrant a new ecu?

The hitachi chips in the 2K-2K1(HD64F7055) have a flash lifetime of approx 100 flashes. I'm not sure the 2K2-2K3 have the same chip with the same flash lifetime. If you can take a picture of the ECM /chip when you get the one from the junk yard I'd appreciate it. (thanks)

Also, If you wish to prove it's the ECM, you could place a multimeter with peak hold feature to pin 1 of the MAF, other lead to GND, and drive around. If it measures a voltage >4v, that is most likely a smoking gun it's the ECM. There is no doubt that there is a design flaw with the MAF, but nissan admits to nothing.

This is for studman as well as anyone else with the technosquare ECU, would they give you the .bin file if u asked for it? If yes, can you share it with me? I'm sure they won't give you the upgraded one but ask if they will give you a copy of your OEM.

the highest form of wisdom, is kindness
SHIFT_woosh

 

A couple of thoughts on this topic:

I have an early '02 that was purchased in 11/01 - I did experience a MAF issue - loss of power at around 12k. This problem was resolved when MAF was replaced by dealer almost 15k later under the TSB. Since then, another 15k has passed without issue. I believe the original problem was a faulty MAF and not a problem with the ECU.

It is feasible that an ECM/ECU could be faulty. Theoretically, an ECM could output too much voltage or allow too much current to flow into an MAF causing damage to it.

If you are going to get a new MAF and ECM, then I would discard the old one for fear of damaging your 5th MAF!

I highly doubt that the problems you are experiencing could be caused by a software problem . . . the software upgrades are designed to resolve specific performance or operability issues, often resulting from variations in sensor inputs. I question whether a software update could/would control the power output to the MAF. On the other hand, I really do not know if the power feed/output to the MAF is regulated by the ECM in any way, but if it is (and it makes sense that it is since the ECM gets a reading from it) a flakey power regulator in the ECM could be the culprit here (this could be a bad/failing transistor, IC, capacitor or diode).

A couple more thoughts. Your car may be eligible for the lemon law. And/or perhaps Nissan will replace your ECM if you escalate the issue through the dealership and the Nissan North America? If there is a problem with your ECM then the hope is that Nissan may want to learn about that to problem to improve reliability of future vehicles anyway.

Keep us posted on your progress.

 

He has what some may consider a heavily modded car. I highly doubt he could get the lemon law to apply here.
But both you and Woosh bring up good points that could explain why not all cars have this problem. If he can prove the voltage is messed up comming from the ECU he should have no problem getting it replaced along with a new MAF.

I love the voltmeter idea, that's something we all can do quite easily, specially those that are having problems like Will has had. Even if the voltmeter doesn't hold a peak you can still wire it so it's in the car for a passenger to look at while you drive.

 

Yes, voltmeters are terrific tools. I would suggest using an analog meter rather than a digitial meter since analog meters react a little faster than digital meters, it could make it easier to see a voltage spike/fluctuation.

 

the ECU is a current driver in this case...

 

Bad ECU could cause the MAF to blow, along with a few other sensors at the same time (if they're somehow linked, which I doubt the MAF is...)
From what I understand, ECUs put out a "reference voltage" as part of its operation, which is a power supply circuit for the sensors... the voltage is typically less than battery/alternator voltage, probably to minimize fluctuations in sensor readings due to fluctuations in electrical system voltage. I wouldn't be surprised if the ECU had a Voltage Regulator inside driving that line.

True story--1988 Ford Tempo (my mother's)... car started running really, really horribly (not like it ever ran well before...). ECU was giving me codes all over the place about EGR system problems, ignition problems, MAP sensor, etc... finally took it to a shop. 1 ECU and 5 sensors later, it was fixed. Turned out the ECU's voltage regulator went bad, allowing too high of a reference voltage through to the sensors... and the extra voltage fried the sensors.

 

Well... read this...

From page 186 of the 2002 ESM:
*************************
The mass air flow sensor is placed in the stream of intake air. It measures the intake flow rate by measuring a part of the entire intake flow. It consists of a hot film that is supplied with electric current from the ECM. The temperature of the hot film is controlled by the ECM a certain amount. The heat generated by the hot film is reduced as the intake air flows around it. The more air, the greater the heat loss.

Therefore, the ECM must supply more electric current to maintain the temperature of the hot film as air flow increases. The ECM detects the air flow by means of this current charge.
*************************
For Your Information (and Newbies): ECM = ECU = Engine Control Computer
*************************
Now on with the explanation:

Here's a breakdown of the MAF/IAT Sensor Wiring for the 2002-2003 Maxima:
Pin 62 of ECU is MAF Data (Pin 1) - Shows +1.1v to +5v
Pin 111 of ECU is MAF Power Supply (pin 2) - Shows +5v
Pin 80 of ECU is MAF/IAT Ground (pin 3) - Shows +0v
Pin 110/112 of ECU is MAF/IAT Battery voltage (pin 4) - Shows +12v
Pin 66 of ECU is IAT Voltage Sending wire (pin 5) - Shows +0 to +4.8v

As you can see, ALL wires to the MAF connect to the ECU, with exception of the power wire which connects to battery voltage. There are absolutely no ground wires connected to the MAF except by way of the ECU. Per the description from the Service Manual above, plus my research into the design and flowchart of the data, the failure WAS caused by the ECU increasing the voltage to the MAF to the point of overheating (and burning-out) the hot film element in the sensor.

[Edit]When the MAF sensor blows, wire number 3 is what breaks inside the sensor itself. This causes the flow of voltage in the ECU to sustain at +1v, which throws the SES light.

 

woosh: I'm not sure of the card color, but I'm having the car re-diagnosed with the failed sensor tomorrow. I am also having the secondary ECU programmed to work in my car as well. Then I will have the TS ECU checked out for some reference values. Once I know more, I'll post it up here.

 

When was you car made? Was it October,2001 or after. if it was after 10/01 then thats why you are OK

 

The ECU does not force feed current, the MAF draws it. The ECU supplies a voltage, the MAF is the draw of current from that voltage source. (E=IxR)

Thats why your ECU is not the cause of a MAF failure.

 

by saying 'current driver' I don't mean that ECU forces current... I mean that the ECU has a driver on the pin that is capable of supporting a sustained current flow from the pin going to the MAF... Something must change for the current to change... either the voltage, or the load, which is in this case the hotwire. The impedance of the hotwire changes with the decrease in temperature and thus the draw of current is increased.

 

Just curious... where is the source of this info?

If this is correct (sounds like a burned out ground wire), I wonder if it's possible to take a "blown" MAF sensor housing apart and replace the wire with a thicker wire... i.e. make a "beefed up" 2k2 MAF sensor

 

Mine was made several months before that.

 

For the pin 3 breaking issue, I measured a bad one versus a good one myself. I have them sitting right in front of me.

For the rest of the research, the ESM.

 

Studman,

I know it's a long shot but if you know the techs well enough can you ask them to borrow/copy the update cd for the consult II and copy the .bin files? Also ask them what color cards are in production these days?

Also can you share that hitachi/jecs part number for the MAF. I want to see if I can find the white paper.


thanks
SHIFT_woosh

 

woosh: I have the numbers at home. I'll post them up when I get home. In the meantime, I am heading up to a dealer where a friend of mine works in sales. I am pulling some strings with the techs in the service department and seeing if I can get the Consult-II from them for "a little while". I don't know if I'll be able to get the update CDs, but I'll see what I can do. What I do with the Consult-II unit in my "little while" of time is all up to me. We'll see how it goes when I get there. I'll let you guys know later tonight (or tomorrow) once I'm done with the unit.

 

woosh: I couldn't get the update CDs, but the card they are running now is purple. They are still utilizing the red card as well, but the newest one is purple. Also, I talked to Hitachi today. They re-directed me to a person over at Ford whom is supposed to return my call this coming week. There is no Hitachi part number for the unit, as it is the same as Nissan's. However, they did say that Ford MAY sell just the sensor alone. They also eluded to the fact that you may not have to go through Ford to get the sensor. It may be available for order at an auto-parts store. But I haven't confirmed this with anyone as of yet. More to follow later on.

Everyone: The new MAF arrived today and I am now operational again. The MAF sensor was installed this afternoon. I then reset the SES codes and started the car so it could identify the new MAF. As for the ECU, it shouldn't be destroying the MAF anytime soon, as I got the Technosquare update while the car was down.

My secondary ECU that I ordered was faulty. I am returning it back to the vendor and will try to locate another one. More on that as the situation furthers.

 

studman:

Can you post the MAF hitachi part number or the part number you have? I'll check for the white part.

thanks
SHIFT_woosh

 

Wow, four AFM failures

I'll bet you have altered in air intake system with some of the franken-crap or what have you.

If it were me I put it back to stock.

remember , if it ain't broke, don't fix it.


and by the way, the ECM will not cause the AFM to go bad.

 

studman:

If you still have the other ECU out of the car can you take a picture of the microcontroller used in your ECU?

much thanks
SHIFT_woosh