Hello all,

I would like to pick your brain before I go about getting a refurb ECM for my 2002 4runner. I have searched anything I could think of and tried everything I found within my ability, so here goes...

'02 SR5 with 156k miles, new to me. I bought it and was told that the ECM was bad and needed replaced. Symptoms were that car would start and run fine with no engine codes (seemingly normal throttle response and acceleration, but I don't have anything to compare it to). After you shut off the motor, you can turn it back on fine, but the check engine light stays on and the VSC and Trac lights stay on. Engine code is P1633 ECM malfunction (ECTS Circuit). If you "reset" the ECM by pulling a fuse or disconnecting the battery, the codes reset and the car works normally again.

So, I don't think I remember all the things I've checked but they have included: checking for continuity through the ECTS circuit, checking fuses, checking voltage going to ECM of +BM, checking the operation of the TPS, throttle motor, cleaning throttle body, cleaning the MAF sensor, replacing spark plugs and wires...that's all I can remember off the top of my head.

Again, the car works fine the first time it turns on (which makes me think its not a faulty part besides the ECM). Any other suggestions of things to check before dropping $400 in a refurbished unit?

Thanks for the help.

found this link:

P1633 Engine Trouble Code - P1633 OBD-II Diagnostic Powertrain (P) Trouble Code | Engine-Trouble-Code.com

These are some areas to check also if you end up getting one from a wrecking yard may consider pulling anything that the above link says to check like O2 sensor.

If you know some one with a same model ECM you could try putting yours in there car it would be safer than putting there's in yours. If your system wiring has a short that caused the ECM to go bad it will show up in the other car but if you have a short in yours it could damage there ECM. Just Saying...

Hm, interesting. Thanks for looking for me. That's not a website that I found or info that I've been looking at. The only thing I'd say is that I've read that this engine code means different things for different maufacturers, and toyota is the "ECM malfunction (ECTS circuit"

As for the other ECM, I don't know anyone with the same model, but that is not a bad idea...I may know someone with one that would work. I did purchase a unit from car-parts or ebay with the same model # but I don't think the VINs match up so it doesn't let me start the car (and I haven't been able to figure out how to reset that VIN cheaply)

ebay has a listing refurbishing your ECM for 89.00.

Yeah, here is the '02 Toyota FSM. Not much choice. Get a new ECM.

http://www.teamtoyota4x4.org/archivi...fe/cip1633.pdf

It's a long shot, but I always double check the engine ground by the diagnostic plug on any code I can't otherwise fix. Remove, clean, replace. It loves to cause weirdness, and it's a free fix if it works.

Yeah, I'll definitely check that. Thanks for the suggestion! Unfortunately that is a lot of what I've been seeing too...just replace the ECM

Just as an update to anyone looking at this thread later on down the road: I haven't made much more progress on the ECM malfunctioning. I tried getting a "new" used ECM from ecmoutlet. com and was very unimpressed with them. Long story short they said they had the right one in stock, I paid for it, didn't get any feedback from them. Two weeks later I call and ask the status and they said they were getting it, two weeks after that (and no communication) I had them cancel my order. Back to square 1.

The other day I ran across an idea to hook up a switch to a fuse controlling power to the ECM to cycle it and hopefully have it start normally. I tried all the fuses inside the cab that I thought would affect the ECM and didn't have any that reset the CEL. I didn't try the EFI fuse in the engine bay, I think that will be my next course of action.

I did narrow down which plug into the ECM causes it to reset. Looking at it in the cab, if I unplug the furthest plug to the right, let it sit for 10sec and plug it back in, I can start the car normally. Hoping this leads me to a place where I could wire in a switch to reset it every time before I start the car? We'll see.

You won't pass inspection with it like that (if that's a concern), monitors have to be ready and never will be if you keep cycling power. Where did you see something relating to ECTS? And by that, is you mean the coolant temp sensor? Quick search on the code brought up stay alive power voltage too low, which would suggest too much resistance in the wire feeding power to your ECU, bad fuse etc. If you haven't already, subscribe to Toyota's TIS site for a day and download all the wiring for your truck, will be able to pinpoint this and more that way. Would think you'd have no trouble finding an ECU on ebay, just pull and match part #, but if you have a 3.4 with 5 spd trans it'll cost you. Auto trans ECU should be cheap. But if it's a wiring issue a new ECU won't fix it

@jbtvt thanks for the response! So, passing inspection is a problem that I would like to fix. Have a few more months before I cross that bridge though. I saw ETCS in the engine code (Toyota P1633) which gets thrown in the scenario in my original post (starting it up the second time w/out disconnecting battery/power to ECM). I need to refresh myself on all the things I've checked but I have checked all the fuses and some wiring continuity. I did just check the voltage to E14-16 (+BATT running to the ECM, should be powered at all times according to the ecm wiring diagram). It was 11.8V with the car off, no keys in ignition. 14.7V with it running. Finally, I did buy a used ECM on ebay (SR5, 4x4, automatic) but when I plug it in, there is another check engine light that indicates that the ECM isn't communicating the right VIN to the BCM, and it wont even crank. Do you know of any ways around this? I've searched around but didn't find anything too promising.

Power sounds alright. If nothing else pans out it might be worth opening the old ECU to see if you have a swollen or leaking capacitor. Shouldn't be the issue in '02 but easy check if you already have it out.

ETCS makes more sense than ECTS for a start issue. Check the DBW connections? My 3.4 is a 97 throttle cable only can't help with specifics.

Only time I had to mess with an immobilizer was when I lost my only key to an LS so had to get a locksmith involved anyway. You might try doing this - YouTube