2001 Toyota Solara ECM Replacement

After taking my car to the Toyota dealer to troubleshoot a car-starting issue, they told me that I needed to replace the ECM. As they wanted $1,100 installed, I told them I’d take the car back and try to figure something out. I bought a used ECM and just tried to install it. My question to anyone who can tell me, the installed ECM has a number associated to it (TN175200-7580) disagrees with one number of the used one I acquired (TN175200-7581), despite the seller indicating to me that it came from the same type of car I have (2001 Toyota Solara V6) - should this make a difference? The other funny this is, I look up my number on the web and come up with nothing, but I look up the number I received and it indicates the type of car that have. Any advice would be appreciated.

I cannot tell you what the difference is between those 2 ECMs. Whether that 1 number difference is going to cause a hiccup or not I have no idea but I’ll do some parts digging to see if anything crops up.

The main thing I would like to know is how the ECM diagnosis was arrrived at and the details behind any car starting issue. The ECM may or may not be the problem although granted, I’m not privy to any info on symptoms and the diagnosis.

The difference in the part number could just involve a revision update to the component. This could be as simple as a change to ECM housing. Plug it in and you’ll find out. But I bet It’ll work.


Have you asked at Toyota what they say? If you go to the parts dept when they aren’t busy, I expect they’ll be able to help you distinguish between the two part #'s. After all, that’s what they do. Your part? It may or may not work. The difference might just be the model year. Or the option package, etc, which wouldn’t affect the powertrain software. But it could be the type of engine – high performance or base model – or the type of xmission, manual or auto, either of which might prove to be a problem. I concur w/Tester, it seems unlikely plugging it in and seeing if it works will do any harm. It would be safer to ask someone at the Toyota parts counter first though.

I would go with Tester on this one. I just helped my uncle install an engine and ECM in his Solara. The numbers on the ECM did not match but it worked perfectly the first time the engine was started. I have a feeling that the numbers change on many components on nearly a weekly basis during the production run.

Thanks all for the advice, I’m going to give it a shot this weekend. Just to share, the weird way this ECM is misbehaving is that when it gets below freezing it cause the car to reliably refuse to start. After getting it back from my local dealers (who diagnosed it as an ECM issue), I tried getting it started this morning (28degrees), and it wouldn’t ‘catch’ (it cranked, but didn’t catch). I then put a hair dryer on the passenger side floor, shooting its air under the glove compartment, waited 5 minutes, and it started right up. In the past I’ve approached it from the mechanical side (tune up, manifold cleaned, new battery, fuel-injectors cleaned) but no go. One thing I have to ask, for this unit to work does it have to be grounded against the cars firewall? Reason I’m asking is the used one I bought on ebay (where the seller guaranteed it was in working condition) my buddy unplugged all the inputs from my original one and plugged it into the ‘new’ one (so we didn’t pull the old one, just had the new one hanging under the dash) and while the car turned over, it never ‘caught’ - after some pondering my buddy theorized that maybe the unit needs to be grounded which is accomplished when its mounted under the dash. So until I fully install this, I probably won’t know whether I bought a bricked ECM or not.

The ECM does not have to be grounded for the car to start. I have driven cars into the shop with loose ECM’s.

If this vehicle is imobilizer equipped (it should be) you will need the keys from the replacement ECM vehicle. Look for a blinking security light with the ignition on. The transponder in the key must match the computer. On Toyota’s early systems you cannot program a new key without a working master key.

If you can get the keys that go with that computer remove the button assembly and install it in your key, this way you will have a transponder that matches the computer and a key blade that works in your ignition lock.

Diagnosed as an ECM issue by the dealer doesn’t necessarily mean it’s a correct diagnosis.

ok4450, I agree with that, another reason I wasn’t paying them $1,100. Although they may have gotten it right, because I’ve run thru most common contributors to no avail, and now that I use the “blow dryer method” it starts (after letting it blow on it for 5 minutes).

Nevada_545, interesting that you would say that, I didn’t know I needed it, and the seller didn’t include it, maybe they assumed I would “flash” it. When you say “early systems”, do you have any idea what year? And if the seller does not have the key or is unwilling to part with it, do you know what options I have?

I’m with OK4450 on this. ECMs get blamed for difficult-to-diagnose problems, but in truth they’re rarely the cause and the problem persists. I’d like to know far more about the problem and the dealer’s diagnosis before feeling comfortable with it.

I understand the skepticism from all who don’t think its the ECM, but I’ve been dealing with this for over a year, and it comes down to specific conditions. If the temp falls below freezing during the night, it will not start until the temp is at least in the low 40’s. This happened last year, but to get it to a mechanic I had to have the right conditions - it had to be drive-able to get it there, but then assured that it would fall below freezing for the mechanic to look at it in the morning. Last year in NJ those conditions never seemed to coincide, so I was left with taking it to a mechanic and describing the circumstances, so I got a tune-up, new battery, cleaned the manifold, did some dry gas, changed fuel filters, and finally my buddy thought the injectors were crudded up, so I ran thru several bottle of STP. It comes down to this - it starts and runs fine throughout the year when the temps are above freezing, but let it get below freezing for a period and all it does is crank w/out catching. While I don’t recall what the dealer service said (b/c I was annoyed for other reasons) they were able to test it in the morning, as the conditions did finally coincide, and they said something along the line that the ECM didn’t ‘know’ the car was cranking. And for the past two mornings since I took it back, it refuses to start up (freezing overnight) but I take a blow dryer, direct it on the blow under the passenger side dash where the ECM is located, and after 5 minutes it starts up. So as bizarre as it sounds, there must be something that is expanding and contracting due to cold/heat w/in the ECM.

So now my question to anyone is, I got an email from the guy who sold me a replacement ECM on ebay, and he doesn’t have the transponder that is paired with it. My buddy has an OBD meter, is it possible to reflash the ‘new’ ECM, or maybe I’ll get a key made and pair it with this ‘new’ one? From what I was reading, the immobilizer is different than the keyless remote, right?

Early systems (1999-2005) didn’t allow a new key to be programmed without a existing master key as a security measure. A proceedure was developed to reset the computer for some vehicles so that if all keys were lost new keys could be programmed. See bulletin.


That bulletin has been revised to include more vehicles but not the 2001 Solara.

For vehicles not on the list Toyota has a program to replace the computer free of charge for one time only if the customer agrees to puchase two new keys. This would not apply to used computers puchaced on Ebay (if the dealer found out).

Hmmm, I wonder whether the ebay ECM is one that was replaced during the recall, which might account for the one number difference? If this is a replaced one, what would be the standard procedure?

Not a recall, lost key computer replacement program. Check your part numbers again. There should be a number that starts with 89661-*****.

@njcarowner61 … fyi, there are companies that will fix a broken ECM. The one I’m familiar with is called “Module Master” or something like that. I’ve never used any of them so I can’t offer recommendations one way or the other. But I think MM is a pretty well established company with many customers and it is getting to be a fairly common thing to get a module repaired rather than buying a new one. But there are other companies too. Google should find several of these companies for you to call and ask if they can repair yours. That might be a better solution than putting in the wrong part # and hoping for the best. Plus they may have the needed expertise to answer your questions about your current situation.

While broken ECM’s are not a frequent cause of auto problems, they can indeed stop working. One common problem is the differential thermal expansion of the various materials used on the circuit board. One material expands more than the other say, which over times causes something to flex and break. The temperature range inside car passenger compartment can be extreme, much more than in a home. So the temp cycles eventually stress the circuit board and causes the signal traces (which are just very thin strips of copper glued to the fiberglass circuit board) to crack. Then whether the trace connects and the ECM works or not would depend on the temperture. If you look at your non-working ECM with a magnifying glass, you might be able to spot a crack in one of the traces.

Re the comment about the need for grounding the ECM, I expect this varies from car to car. I assume you mean whether it is necessary to screw everything back to the mounting brackets. On some cars it might be necessary, not so much for the grounding function, as that would usually be done through the wiring, but because the mechanical connection to the mounting brackets might be part of the heat sink, necessary to keep the parts from getting to hot.

Best of luck.

The ebay ECM has the number 89666-06181, found a website that states this was replaced by 89666-06182-84, so I’m guessing this one can’t be flashed.

Maybe. The parts department checked that # and told me is cam from a 2001Camry or Solara.
The reset proceedure chart lists Camry and Solara seperatly. I don’t know why if they both use the same computer.

The next problem is that you’ll need a dealer level scan tool and a pass code number from Toyota.

I’m beginning to suspect that my safest course of action is to have my semi-working ECM rebuilt, and deal with being w/out the car for a few days. I figure rebuilt fee (250 on one of the sites I found) + a few days of car rental still easily comes in below $1,100

Keep us informed as the final result could be an assist to others who might suffer the same problem, but I’m still dubious (very, actually) about the ECM thing.

I can provide no help on this but the one thing I would want to know right off the bat is what’s missing when the engine is being cranked over; gasoline or spark.

Funny thing happened today - I had found a place in Texas that advertised rebuilding your ECM, and I called them just to verify that could help me out - they would charge 40 to look at it, and if they could find the problem and fix it, the whole thing would be 250 (that includes the 40). He also stated if they couldn’t rebuild it, they would offer one of theirs, which then led into a discussion of immobilizers and they ebay purchase. He helpfully told me that I should install the ebay ECM, then call a car locksmith. I called around and there’s a 24/7 place that is willing to come to me, I of course have to have proof of ownership (just found the title when I was recently cleaning out my office) so I’m good to go. I’m going to give it a shot this Saturday.