Amethyst643

Everytime I reset the codes, code 36 comes on soon after and stays on. I looked it up and it is a "MASS AIR FLOW BURN-OFF CIRCUIT" problem.

I found wiring charts and instructions on the internet on how to test and fix the problem. Now I'm stuck.

Here's the process I've been following:

1.) Clear codes by disconnecting the battery wire for more than 10 seconds. Start car, run, then turn off. Turn key into "On" position to check for codes. This is when code 36 becomes lit. It is the only code that shows up.

2.) Disconnect MAF Sensor Burn-off Relay. Probe both 340ckts with a test light to ground. They both light up like they should.

3.) Reconnect Relay. Disconnect MAF Sensor. Ground Burn-off Relay ckt 900. Probe MAF Sensor Harness terminal "D" with a test light to ground. This is the part I do not know how to do since I'm not sure how to use a jumper wire. Now, the wire in question is black and runs from terminal F of the MAF Sensor Burn-off Relay to terminal D12 on the ECM. Once that wire is grounded, I am then supposed to test terminal D on the MAF sensor harness.

Here is what I did.. I peeled back a little bit of the black wire coating so you could see the wires inside (at about an inch before you get to the Burn-off Relay) and then put the clamp on it where it was touching the wires. The other end clamped onto metal to ground it. I then used my test light (grounded) to test terminal D on the MAF sensor harness. In fact, I tested all of the terminals on the harness, and none made the test light light up.

Really my question is "Did I use the jumper wire correctly?"

If I did, then I would go on to step 4, which is to test terminal E on the harness. The wire going to it comes from the MAF Power Relay. I already know the test light doesn't light up when I test terminal E. So I'm thinking that I may need to replace the MAF Power Relay.

Thoughts?? I've really never done ANYTHING like this before and I have no idea what I'm doing. So any input or ideas would be useful. Thanks!

Amethyst643

Here is the ECM, under the passenger-side of the dash:


Here is the MAF Burn Off Relay (left) and the MAF Power Relay (right):




Both have the same part number.. 6230 - 14089936:


Here is the MAF sensor harness:

engle1147

That circuit can be a little tricky. The MAF burn off relay only engages for just a few seconds after start up then its job is done until the next start-up.

Your MAF relays look like the origionals swapping them out for new ones will not label you as a "parts swapper". The relays are ~ $15 each. Look inside the MAF sensor to ensure your filiment wire is still intact.

Amethyst643

Couldn't take a picture of the inside of the MAF sensor since there are screens on both ends. So, here is a paint drawing of what it looks like looking toward the front of the car:


Looks okay to me!

btr85vette

The MAF is powered by a fuse labeled "Gauges" I belive. The FSM diagram will show it and what it's called. Make sure it isn't blown. Mine blew and the MAF error displayed.

Amethyst643

Just checked it. The "Gauges" fuse is fine.

C409

Replace the relays ... they're about $15 each .......

Amethyst643

Okay. I just went and bought the replacement MAF Sensor Power Relay. After removing the battery cable for a few minutes, I reconnected and started the car. No check engine light. Then I drove it up the road and back, shut it off, and restarted it. No check engine light.

But then, I turned it off, and back into the "on" position and checked the codes. As soon as the paperclip touched it, the check engine light came back on. It showed code "36".



So I'm thinking "now what?" I repeat the process starting with the battery cable.... Same thing happened again. The check engine light never came on unless I went to check the code.

Does that mean the code is there or not really there? What do I do?

Have2join_2

Hi All,

This thread seems to be a common fault on particular C4's. I have a stock standard '89 with the following problem(s). Following an ECM reset, (that is: battery disconnected for a minimum 30 seconds), I can drive the car for days without anything appearing wrong. After about the 3rd or 4th day on comes old faithful (the SES light), with a fault code of 36. If I repeat this ECM reset, same result as stated. I have changed the relays, MAF, cleaned all the associated connectors up to and including the ECM. For the majority of the time I drive the car with the SES beaming in my face and snarl at Chev for most of the time, since this code 36 could mask a real SES light on problem. Now here's the wild card: if the ambient temperature of the day is above 80F then the SES light will go out and the car acts like a Corvette should with no SES light for a couple of days. And then will go back to the 3 day cycle mentioned first. This result is of course when the ambient temp goes below 80F !!! It would seem to me that whomever wrote the ECM software in this "burn off" cycle did not do a reliable job. It's operation seems amazingly flaky at best. What really cheeses me off is that even the GM Approved Tech I scan tool can't reset a code 36 for this model. From reading the thread here, and you live in a high temp location (Las Vegas) then information presented in this thread is astonishingly true. But beware there are other "features" of the "burn off cycle" that will remain unknown to man nor beast. I thought I would share this with anybody who is following this thread and issue the following warning: don't be buying parts at random for substitution based on the Service Manual, and it may take you a few days (or years) to figure out that you can't fix this fault by replacement. I am of the opinion that the PROM replacement is possibly the most correct answer for an intermittent Code 36 on 87,88 or 89 Vette. Unless of course you have a "hard" error in the MAF system, but then the code 36 would not be intermittent.
If I ever fix this on my car I will update this post as to how, and blame the correct faction, as I understand the ECM is not a Chev built part, but they chose to install it. Regards to All.

Amethyst643

Since this thread has been brought back to life, I guess I should conclude my story...

So the codes kept coming up. The reason ended up being that the MAF Power Relay needed replacing, not the Burn-off Relay. So I switched them, and that fixed it. No codes.

Till a few days ago when I washed the car at the carwash. I guess a lot of water got into the areas where the fog lights are (there are a lot of wires down there). Some how that made code 36 come up and stay on - plus the car wasn't starting right after that. So I went and bought another relay, replaced the MAF Burn-off Relay, and that fixed it's starting and got rid of the code.

So now I have 2 new relays and no codes (for now). Not sure if the water thing is what really messed up the Burn-off relay or not. Guess I'll be washing the car by hand till I find out..

george4

I purchased my ’89 new and have a few observations re connectors, including ones that give a code 36 and dash lights to misbehave. Clean both sides of connectors well including spraying them out with a fast drying pressurized contact cleaner. A small pencil eraser, cut to a handy shape, works to clean up any metal parts of the connector you can get to, this helps to get a good electrical connection. Use the small tube that comes with cleaner to flush them out well a couple of times. Place a rag under the connector to catch the run off. If the connector has a weather ring around it, smear a little silicon grease on the ring, it will make the connector go together easier, help to get it fully seated and make a better seal. Sometimes it just a bad connection.

Amethyst643

Someone told me that it might have just got water in the distributer while at the car wash. Not sure why code 36 would have came on if that was so....

By the way, I think this smily is gliched...

Have2join_2

Hi All,
The continuing saga 89 model code 36, I have now replaced the ECM with one from Ebay (sorry yes Ebay but it was $36 ) from a different model (some GM 91 model not Corvette) car, when I pulled the ECM apart all circult board markings matched the original, so I just changed the PROM to the Corvette one and put it all back together. Also since the Burn-off relay and the MAF relay are the same you can simply swap over the connnectors for the relays. For me this was change the location of the gray and black connectors. But be warned this might have been done by somebody in the past (if you don't have the complete history of the car). An interesting observation on the ECM is that the one taken out from the 89 had a remanufactured ECM with many modifications to it , when compared to the original 91 model. I'm now in my 3 day cycle thingy so I can't tell if it's fixed by this or I'm just being toyed with still.

From the last post I would doubt if a car wash would affect the burn off system. I'm sticking with my "flacky at best" statement for now. Till I get better educated or fix the thing for good.

Just to add to the flaky story I bought a complete wiring harness from a '90 Corvette since I wanted the CD/Radio harness. When I stripped out the radio side of it, there were joins in the harness for other functions, not cripped nor soldered just twisted together, so be warned all you Corvette owners, if your car has electrical gremlins try wire substitution for harness problems. It might be uncool to have one or two extra wires on the car for a coulpe of days, but will stop you going insane trying to find an intermittent electrical connection in the middle of a harness run where there is not supposed to be one!!

Have2join_2

Dear All,
I ended up correcting the intermittent Code 36 with the replacement ECM. The original ECM for a '89 is a 1227165, but this is superseded by 16198259, but again this is superseded by 99888194. With my collection of ECMs for this car I have noticed that there is a variety of internal modifications to the ECMs internals. You can get the schematics for the 1227165 off the internet (use Google Search). But I suspect the manufacture of the ECM has been constantly changing the firmware burnt into the chipset for the ECM, which is why the ECM keeps changing part numbers. Many thanks to the contributors of this post as their tales of similar problems kept me from going crazy on this one. And, yes it's nice to drive the car without the SES on all the time and it's 41 deg !!!!
Me.

AJ123

I have changed the relays behind the battery on my 87. Have a new MAF. been cleaning and checking wires no luck yet still code 36. Anyone find a magic answer yet.

Have2join_2

The old code 36 issue .... The result (for me) was to replace the ECM Computer. My car System is really sensitive to daily temperature and after investigation I can engineering-ly understand why. The computer I put in was a 99888194 but exchanged the '89 ECM EPROM. The burn off part of the ECM software would therefore be the same, this whole system it's a really big compromise between burning out the MAF and burning off the collected grime. Let me know how you go, if it really does not get solved for your car, I can blow the dust off my old notes and suggest a modification for the circuit. But with a warning my permanent fix will disconnect the ability to burn the MAF at all ...... users would have to manually clean the MAF sensor every 6-8 months depending on use.

AJ123

I replaced the ecm while working on other codes recently.

Right now when I have time I am going to check this out. I may be getting back to you. this is driving me nutts at the moment. Thanks Steve


http://www.corvetteactioncenter.com/f ... relay-sockets-issues.html




The quick fix was to remove the socket and attach a female spade connector to each wire and slide them on to the proper relay blade individually. It has now been 4 months and over 20,000 miles with no issue. The only problem now is where do I get new sockets? I don't want to get ones from a salvage yard that are well on their way to developing this same issue - See more at: http://www.corvetteactioncenter.com/f ... html#sthash.dEo6CPep.dpuf

Cliff Harris

MAF burnoff is done when the ignition is turned off. The ECM stays alive for about 10 seconds to do the MAF burnoff and to reset the IAC. The ECM must be in closed loop mode when the ignition is turned off for MAF burnoff to occur.

The MAF burnoff relay applies 12 volts to the MAF sensor wire. That causes it to glow red and burn off any deposits that may have accumulated. During the burnoff cycle the ECM looks for the MAF output voltage to be between programmed values (400mVDC to 1.90VDC in my car). If the output is outside those values then it will set error code 36.

If the burnoff relay is bad then burnoff will not happen. Over time the MAF output will deteriorate and the engine will not run properly.

kitttransam

I know this is old. But I just had the same problem pop up. Code 36. Car runs fine but that ses light is annoying. My relays were already new and maf isn't that old I replaced it a few years ago. And I haven't driven it much. I did try swapping relays. Same result. Cleaned maf and connections. Code still popping up. I believe I have the same part# ecm that's outdated. So I'm thinking about getting the newer one to see if solves the problem.

puzzigully

I feel your pain

I've swapped out relays several times, 4 MAF sensors and one ECM, still have the problem.

Got fantastic help from the guys on here and managed to use Tunerpro to actually "see" what the ECM was seeing in terms of "burn off" voltages.

In my case the burn off voltage was too high, no matter what combination of MAF/ECM/Relays I used.

The only chopice left for me is to either:
1. Disable the code 36 reporting (so that the test/burn off still occurs and any other code is reported by the SES light) or
2. Expand the parameters for the test to accept the higher value, thus it won't "fail".

I'd suggest you try to see the burn off voltages before you go too much further.