ECM problem

Have you tested the scanner cable as yet, and is this second wire brown or brown/white as the diagram shows no brown only.

mark

i tested the scanner cable and the only continuity was between those same two terminals. The two wire colors are : white/black and also brown with silver or white tracer dots. I am thinking this is the wire shown as brown/white because it is the only "brown" wire on the connection.

Am trying to find out what the pins on the data link that you bridged go to, this is driving me insane trying to get this sorted...lol

mark (mhpautos)

what is cg and sg?

I have no idea , and there is no indication in Mitchell 1 either, this is what i am trying to find out.

Mark

well, I know the wire is getting hot. there has to be on the schematic what we are jumping out. It looks like the electronic wiring diagram only shows the two wires going to the firewall and the other to the dash, and that is all that the diagram is showing. It does not show where the two wires continue onward to.

we have to figure out what these two wires are jumpering out. White/black & Brown/white

is this a Sienna CE, LE, XLE?

it is a CE model 6 cyl auto, jumper those two wires and the van will start and run.

I went to a Toyota Dealer here and they have no information on Sienna as it is not marketed here so they don't carry manuals, maybe Jack can find out a bit more,

Mark (mhpautos) in Australia.

somebody on toyota nation . com suggested that I read out resistance on the brown wire to ground and the white wire to ground.

Definitly Ohm them out to ground.I cant seem to find the Brown/white wire in theschematic I have (Mitchell) but the White/black goes to a ground behind the right side of the dash and it shares that ground loop with the "Transponder Key Amplifier" So if this gound circuit is bad, it may not be seeing the key in the ignition which would expalin why it wont run

i read out the brown/white tracer wire to ground and I get continuity to ground with 8.1 ohms on a (200K) setting on the ohmeter. When i read out the white/black tracer wire to ground, I get .5 ohms on a (200) scale. White/black wire continuity but no resistance?

Both wires should be good grounds, like the white/black.I found the other in the ground dist wiring diagram.looks like you may have a bad ground that is being substituted by the jumper when it is plugged in

A number of techs have suggested that the key reader (key amplifier) may well be the problem, do you have alternative keys to try out?

mark (mhpautos)

well, this particular van does not have a transponder chip in it. When I got keys cut i never had to program a key. It is a 2001 sienna ce. Are you suggesting there is a problem with my key not having the proper transponder chip that is correctly working in it? I just went to a hardware store to cut a new key before. I DO HAVE another key that I can try and let you know. But, I am almost certain the key has no high tech functions. Where is the key amplifier by the way?

i tried another key and it did not work.

Did you check the ECM grounds on the diagram I posted?If it runs with that grounded and the ground circuit has that much resistance for the ECM it cant ground on its own.The white/black has good continuity to ground,I dont think its the problem, the other should have the same but doesnt. The key may not need a chip, just sees a key going in so it knows it isnt being hot-wired

It is hard to read the schematic, i will try more. Is it possible to send a better one or hand draw something?I cannot see what you are talking about, but we are getting very closer now!!! So, the one wire has higher resistance than the other , does to ground? Is that the bad circuit because it has so much resistance 8.1 vice .5 ? when you read the diagram what do you think I should do next? So maybe the key in the ign. reader is on my van for sure? Is every 2001 sienna built with a key amplifier that reads the key in the ign.?

There is a main ground on the right side of the firewall that the ECM uses as well as the data connector.Im sure they all have a key reader, it has been used for a long time, since the chipped keys turned out to be kind of unreliable

Can you guide me as to what to do next? Find the right hand firewall connection and do what? Then what do you think ? Replace the key amplifier?

With out having the car to work on, i can't tell you exactly where this is, if i could view the wiring it can be sorted out what is what, maybe its time for a mechanic to view this with all the information you now have, i can't be your eyes for this part of the diagnosis, you have the colour codes, that is all i would have to work with as well, as for the amplifier, this may be a serious option to consider, but i would get a mechanic to check our findings so far first hand.

mark (mhpautos)

do you think the ecm itself is still good? where is the amplifier located what does it look like. what is the theory of operation?

Since the ohms are so high to ground, you will need to find this ground and be sure it has good contact.It will be near the main wiring harness, you will have to look for it,Mitchell doesnt give the exact location, just general area.The continuity to ground should be the same as the other wire.

so the one with 8.1 ohms is the problem? look under the dash or under the hood?

It just says right side of firewall. look under hood adnunder dash to see if you can find it.Use your meter to continuity check if it is the right set of grounds once you find it. Yes both should be very low resistance, they are both straight grounds, but the high one is hooked to the ECM and the key amp, so if it is bad, it will use the other good ground when they are linked together at the connector

Check the earths as indicated, this pic may help locate them, it is the best that Mitchel 1 has.

Mark (mhpautos)

what are the 2 red arrows pointing to? The connections are labeled what numbers? I noticed a connection under the hood near the air cleaner box which is bolted to the side of the van (inner fender) and grounded.

The arrow is indicating the vehicle earth points, there is no indication in Mitchell 1 as to where the exact earth point is, short of purchasing a factory manual i can't pin point the earth points any closer than this, a trained tech will see this diagram and have the ability to look at the car first hand and locate the earths looking at the loom, i can't be your eyes for this part, earths are normally a group of terminals if you follow the loom it will be apparent, when located you have the colour codes to start doing what jack has suggested.

mark (mhpautos)

OK, I will let you know what i find out. I will just find the wire and see why it has so much resistance to ground.

i found the ground(earth). It is the upper right corner by the air cleaner box. I unbolted the wire from the fender and read from the data link connector to the terminal where the three wires meet and the brown one seems to have continuity but high resistance. here are some photos to help us out............

any ideas what to do with the brown wire?

Judging by the diagram I posted before, teh brown is to the key amp and the wire from the data link connector is brown/white.Im know it is a few bucks, but you may want to consider getting a Mitchell1 sub for a day and printing out all the wiring diagrams so you can see all of what we are dealing with as far as grounds go.I dont see anything beyond a bad firewall connection/bad wire that would make that ckt have such high resistance

Why is the data link brown/white wire making continuity to the brown wire? I guess i will have to uncover all the wiring from the data link caonnector to the firewall ground then and see why it has high resistance. maybe the key amplifier is bad causing high resistance. Where is the key amplifier located?

Key readers or amplifiers are normally next to the key barrel, see pic i posted with the arrows, it shows the key amp in the steering column near where the key would be.

Mark,

P.S. I am away for a week so i will not be able to respond, you should have plenty of information now to sort through this problem, and as Jack said, get the access to mitchell any you will have everything we can see.

2 car pro jack, what do you guys mean by getting a mitchell sub. Do you mean a mitchel subsription because I got one for the online manuals someone suggested before.

Yes that is what I meant. if yuo have one go to "electrical" then "wiring diagrams".From there choose "engine performance" and "ground distribution" and you will see how those grounds tie together and what color wires etc...

Well, I took the brown and white wire on the back of the data link connection and soldered a same size if not slightley larger wire to it and grounded it out permanently. the van starts up and runs perfectly and the new spliced in wire does not get hot at all or too warm so that I cannot touch it at all. So by me grounding that brown/white wire the van is fine. I looked at my ignition switch and the mitchell manual and according to where the mitchel manual says that the key transponder is my van does not have one. I double checked and iit does not have a key transponder. So, what did I do by grounding out the brown/white wire? that is the question now. I still want to know

I would say that if you have replaced that earth wire and all is OK, it is not so much a matter of making the earth sound, i would say that in the loom the earth wire and a power supply or signal wire have breached causing the high resistance and all the problems, the new sound earth should be proof enough that this is the case, i would terminate the faulty wire at the chassis earth and just run a new permanent earth.

Mark

i dont know what you mean by terminate the chassis earth. all i did was solder in a brown wire to the back of the data link connector and ground it because the loom is buried behind the dash.