You seem to have covered spark and fuel and compression. The only other things I can think of is security (like you mentioned) or possibly cam/crank correlation (timing chain skipped a tooth or two). I am not sure of the security strategy of this car but suspect that it won't allow the engine to start at all.

 

If it’s security related, the engine won’t crank at all. Do you know if your key is the original? Also, does it have a transponder key? I seem to recall that some matrix models didn’t have transponders until 06 or so. Have been wrong before.

Have you tried to tap the starter housing while cranking? What is your battery voltage? Is the crank fast or slow?

 

If it’s security related, the engine won’t crank at all.

Thank you, I couldn't find anything that seemed certain on this point.

I bought the car used, but the keys seem to be original. 2 keys, one fob, all working without issue until this came up. It does have transponders, but both keys give the same results. Unless the internal component died, I just can't believe both keys went out on the same day.

The engine does crank - it just dies after 1-2 seconds. We've been doing extensive testing, so I charge the battery every couple of days. I don't recall the exact number but there hasn't been a concern with the battery voltage to date. I can provide an exact number later today.

The crank seems completely normal. There have been several times I thought "Oh, it worked!" only to have it die again. It only lasted a second longer than it has been.

 

I assume you attempted to start the normal way, without pressing the gas(?) But will it start if you hold the gas pedal to the floor?

 

That's correct, we have tried no pedal, full pedal, half pedal, etc. No difference in results.

 

You also mentioned that you wiped off the MAF sensor but you have a code for it. I would try starting after disconnecting it. It will run rough (if it starts) bit this could point you toward the sensor. Also it should be cleaned with MAF sensor cleaner; I don't think wiping it would be good.

Also is the air filter clean and the ductwork clear?

 

You also mentioned that you wiped off the MAF sensor but you have a code for it. I would try starting after disconnecting it. It will run rough (if it starts) bit this could point you toward the sensor. Also it should be cleaned with MAF sensor cleaner; I don't think wiping it would be good.

Also is the air filter clean and the ductwork clear?

I was able last night to try starting with the MAF disconnected - same result. I'll try to get MAF cleaner and give that a shot. However, I was able to get the codes cleared, and no engine-level codes are showing up at all now, including the MAF. I'm not sure what it would take to trigger, but I probably did about 50 total starts in testing last night.

We've also tried starting it with the duct work completely disconnected. This also brought the same result. Ductwork was clear (though a lot of Aluminum oxidization), andI have a new filter going forward just in case.

 

If the check engine light was on while the car was running, use a code scanner. If it wasn't on, let's see more answers.

 

It has always been on due to the torque converter clutch being stuck off. My most recent OBD2 report has no active or pending codes, but to be clear, the car barely starts and hasn't run.

 

So it actually starts up each time and the issue is that it only runs for a coupla seconds, then dies? What specific MAF code is in the memory?

 

What you stated is correct.

The previous MAF code was P0102. I did clear the codes and it hasn't come back (just for reference).

 

Wow... strange?
Have you tried having a spray bottle with fuel or a can of starter fluid right at the throttle body when it tries to stall and feed more fuel in there to see if it's fuel starvation or then it must be electrically being cut off? (seems you tried this already)
Maybe you need a more advanceds code reader. I thought most garages there read the codes for free?
Weird one...

 

Wow... strange?
Have you tried having a spray bottle with fuel or a can of starter fluid right at the throttle body when it tries to stall and feed more fuel in there to see if it's fuel starvation or then it must be electrically being cut off? (seems you tried this already)
Maybe you need a more advanceds code reader. I thought most garages there read the codes for free?
Weird one...

Yes, we did try that (just confirming).

I did get a cam sensor I'm going to try replacing, just because it's a cheap part. But after that, I'm completely out of ideas. I'll likely have it towed to a shop to check it.

 

Cam sensor or crank sensor might be the culprits. They can act funny without throwing a code.
Are you close to a junkyard so you could try a used one first?
"Evidence of mice" is a scary thought. This strange problem does sound like a wire is slightly compromised somewhere even though it ran well for the first year. Not throwing a code makes it really difficult to diagnose also, as you are seeing.

 

So, a significant update.

I've only been running the OBD2 codes at the highest level, for the sake of time. My brother brought up to me that some security codes may not flag at the highest level, run a full diagnostic with the sensor. I just did that, and I found a code

B2799 Immobilizer Malfunction

.

So I spent a few minutes trying to read and watch information about the immobilizer system. Seems this info is most often needed when reprogramming the ECU or the keys. So one video pulled out the ECU to do some wiring. That's when I saw the ECU sits immediately under part of the AC system and filter.

Did you know that if your 2006 Toyota Matrix gets a clogged AC drain line, then the backed-up drain can spill over - especially when making sharp left-hand turns. This makes the water spill over in a way that can be seen in the passenger compartment.

The last time the car was driven, the driver complained about the water sloshing noise. But it had happened before, so I didn't think much of it. I'm now assuming water spilled on the ECU and has caused an issue.

But the Dashboard security light is operating and reads normal function. Do I just need to reset/reprogram the ECU? Or does it need replaced?

Man this has been a frustrating journey.

 

So, a significant update.

I've only been running the OBD2 codes at the highest level, for the sake of time. My brother brought up to me that some security codes may not flag at the highest level, run a full diagnostic with the sensor. I just did that, and I found a code

B2799 Immobilizer Malfunction

.

So I spent a few minutes trying to read and watch information about the immobilizer system. Seems this info is most often needed when reprogramming the ECU or the keys. So one video pulled out the ECU to do some wiring. That's when I saw the ECU sits immediately under part of the AC system and filter.

Did you know that if your 2006 Toyota Matrix gets a clogged AC drain line, then the backed-up drain can spill over - especially when making sharp left-hand turns. This makes the water spill over in a way that can be seen in the passenger compartment.

The last time the car was driven, the driver complained about the water sloshing noise. But it had happened before, so I didn't think much of it. I'm now assuming water spilled on the ECU and has caused an issue.

But the Dashboard security light is operating and reads normal function. Do I just need to reset/reprogram the ECU? Or does it need replaced?

Man this has been a frustrating journey.

inspect the pins for the ecu for signs of corrosion. Once confirmed it’s clean, then you will need to do a data dump of the ecu. The ecu holds a certain number of immobilizer ID’s in memory. There is however something you can try.

I will share the info through dm. But basically, there’s 2 pins that needs to be jumped for the key to be recognized. It has to stay in the ignition in run with engine off for about an hour.

Do you know if the PO had the ecu swapped? It’s a big possibility the key was never saved onto the ecu. I’ve done ecu swap and had to jump the pins for the key to work.

 

I had this problem with my Corolla 2006 once. It was after I installed the new ECT sensor. (Engine coolant temperature sensor) I touched some wire near that area and then when I try to start the car it started but died in 2 seconds. Just like your car. Try starting it up again. It died again in 2 seconds. Must be bad old wire connection around the ECT sensor area. So what I did is I touched those wires a little. Shake it around a little. Then start the car. Car started up. And did not die. I watched a video of some guy suggesting people to cut off a portion of their plaastic engine cover. There is a portion that sticks out at the right hand side. I mean driver side. That extra plastic touches the wire. And car be shaking for 20 years and wire near that piece of plastic will get scraped and will be damaged. So cut off that piece of plastic.

 

How about me? Did you see what I wrote?

 

I did see it, but there's not much actionable here

• What wires?
• What video
• What portion of the plastic cover? Any diagrams?
• I don't observe any plastic rubbing on a wire on this vehicle

 

Man good luck with that then. Maybe It cannot be injectors nor fuel pump nor fuel line. Cannot be MAF sensor, because4 it did start. Not MAF sensor's fault. Should not be the ECU computer becaause it did start. Only thing left is a bad wire or air intake leak.

 

Hey while you at it, why don't you try taking off the metal plate that covers the upstream oxygen sensor. I took mine off and car starts right away. I know your car does start but dies right away. But hey, you should try this. After all, you ran out of options.

https://www.toyotanation.com/threads/corolla-2006-hard-to-start-problem-solved-by-removing-a-metal-plate-that-covers-the-upstream-oxygen-sensor.1783960/?post_id=14993559&nested_view=1&sortby=oldest#post-14993559

 

I’m going to say it’s ecu or wiring issue. It was running before and lost all communication with the key. ECU is clueless at this point.

A key programmer will be needed if the ecu is swapped. The tool needed will have to be able to erase old key id and seed new ones. I think the ecu only holds 3 id. Master, 2nd key and valet or grey key. Grey key is usually lost in many key sets.

 

Here in the US, the strategy of the key ecu holds a certain amount of transponders. Master, 2nd key and some came with valet key. As keys are replaced, only so many can be written. Not sure if the ecu handles x number of rewrites.

Need to verify both the ecu to the key ecu for resistance in the wire harness. Then check from ecu.

 

Is the security light blinking though? I will send you a dm. Key not recognized will crank but nothing else.

It was blinking as expected. Unplugging parts of the ECM and reconnecting seemed to do the trick - it runs now - but I have no idea why.

 

Glad to know it’s no parts needed.