Last week, my car would not start. The light for the immobilizer was flashing, so i went through the diagnostic in the service manual and bought a new immobilizer. I went to go reprogram the immobilizer and my obd2 port would not connect. I checked the power and ground and it was fine.

Now, i am pretty sure it is the ecu that is not working, so i need to install a new one. The problem is I have a rare MT 06 TL. From what i read, the 06 is special because it is very similar to 07-08 ecu pinout. The difference is the obd2 signal cable.

I have found lots of 07-08 ecus and some 06, but they are all AT. Can i convert them to MT using the HDS tool? Can i put an AT ecu in my 06 MT?

 

Do you have bi-directional scan tool? That way you can scan each module and really check if ecu is not responsive. You most likely will need to program new ecu anyways so doing anything without good scan tool is pointless.

 

I'm thinking this is a case where if you are "pretty sure" it is the ECU, the odds are it isn't. Said another way, buying a new ECU would be the equivalent of throwing parts at your car. In cases like this, it will probably be better/faster/cheaper to have it professionally diagnosed and repaired.

 

I tested it out with my regular, cheap obd scanner, the knockoff honda diag tool, and a canbus sniffer. The canbus sniffer did not see any traffic.

I did use the ac and this car usually just sits most of the time. There are threads about an ac drain tube getting blocked and draining on the ecu.

 

The ecu is the only thing i have not tested. All fuses are working, everything is getting power, the immobilizer is new. I've gone through the entire diagnostic procedure in the repair manual. There are only a few things that can cause this and they are all working.

The diagrams and instructions in the manual are pretty thorough with each pin labeled. I'm also an engineer and arduino hobbyist, so I'm pretty handy with electronics. The voltage on the comm wire is too stable (no high/low), but i don't have the (expensive) equipment to say i can prove it. So im pretty sure.

 

You have HDS? Then just run the equivalent of scanning the whole car, no idea how it's called on HDS but it should be able to do that. Ecu is not the only thing communicating on the line so even if ecu is dead you still should be able to "talk" to other modules. If no such option then go to something like abs and try to view live data.

Bunch of modules should be reporting loss of communication with ecu. If still no comm only with ecu, then check if ecu has all grounds and powers, or check for water damage if you suspect it.

If you can't communicate with anything, then either wire is broken or shorted somewhere.

 

I'm not sure if I'm using the correct way to connect with the hds. I just bought it and installed it on a windows 7 VM. Do you know how to use it? For me, it says it won't connect over any of the protocols.

 

Why use VM? Did you give the VM full access to the physical device?

 

I have been using VMs for a decade. It can detect the tool. The reason i have to use a VM is because this is some knock off from China. I don't have the official HDS from Honda and don't even know if I can get it. The HDS is also designed to run on windows 7 and i have linux. I also work in a related field.

The device is connected. I have a cheap obd2 that I've used on other cars and it also fails to identify the protocol. I've tested both ground and 12v at the obd2 connector and they are fine. I even connected an obd2 splitter i used for a previous project to map canbus traffic in a different car to test the pins are making contact.

The only way to determine if the ecu is bad by swapping a known good one. This is in the repair manual for a 2004 Acura TL. All fuses in the circuit have power when they should, i followed the immobilizer diag steps, only thing left is the ecu.

The ecu is less than $100. I just need to know if anyone knows if the ecu can be converted from AT to MT. I know the $500 piggyback can do this with 07-08.
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This statement does not match the diagram. All the data lines for the dtc connector (obd2 connector) come from the ecu. If the ecu is dead, you will get nothing. Those are pins 14, 16, and 28 on the A connector on the ecu. I can check these for shorts or breaks, but i would still like the answer to the original question of if AT and MT ecus are swappable.

 

Most likely they are not. There is only a handful of conversion threads, but anyone attempting that so far needed wiring harness and ecu from the MT in order to swap it into previously AT car.




Even if ECM is removed or dead, you still should be able to talk to VSA (abs), SRS (airbag), MICU (body control module or fusebox), and immobilizer unit.

 

Agree. The rest of the modules should be broadcasting on the can bus line unless there is something pulling it to ground.


Have you looked at the bus lines to see the waveforms with a scope?

IMO, the troubleshooting instructions in the service manuals are not the best.

The AT and MT PCMs are not swappable. The car will probably not start the car because you will be missing inputs from range switch, and it will probably have a lot of codes for the AT. However, you should be able to at least communicate with it.

 

Where have you been looking? I found tons of 06 MT ECUs on ebay and car-part.com. Part numbers: 37820-RDA-A24/Acura 37820-RDA-A23

If I were you I would go on car-part.com, find my nearest junkyard and grab one. If one is too far, most of them will mail the part out to you if you pay first.

 

This is a final post for anyone reading this with a similar issue.

If your car won't start and you see the green key symbol blinking, that means the ecu is not able to verify the key with the chip.

First thing is to check fuses in the drivers foot well and under the hood.

Then check power/ground to the immobilizer, located where you insert your key, on the 7 pin connector.

If that all works, next look at your ecu and confirm that your obd2 scanner can connect. If it does not, check the pin for the k line on pin 7 has ~8.5v (04-06 tl), 12v on pin 16, and ground on pins 4 & 5. If you don't have ground or 12v, fix the wire. If you have less than 8.5v (it will fluctuate on a multimeter) on pin 7 ( around ~4v), check the wire and replace the ecu.

If the ecu seems fine replace the immobilizer.

These are abridged direction from the repair manual.

For me, it was the ecu. There was water dripping out when i took it out. I made an expensive mistake by buying the immobilizer, so hopefully this will save you some money.