68HC11 based PCMs

[Tom H]

Hi,

Can anyone tell me details of which GM OBDII PCM/ECMs were based on 68HC11 microprocessors? I am looking for a test mule for my new read/program software for LT1. Where I am, LT1 PCMs are scarce and I am having trouble finding one at a reasonable $. Hope is that a '96 C1500 or Cavalier or other more common car will have both FLASH and 68HC11.

Thanks,
Tom

[kur4o]

You are looking at something between 96-97 with 4 connectors and not a black casing. I will have to go through some files archive to see what can be found. I think some early diesels uses that cpu. Gm tis2web site can be your friend to figure by vin some files p/ns.

[Tom H]

I had a look at the TIS2WEB but without a serial number they don't help you.

LT1s had four connectors... would a 4cyl Cavalier use the same case? I think the truck motors all have the black case, do they use the '332?

Diesel would be fine IF I can find one, again they are not too popular around here.

Wrecker here has about an acre of GM only However most are more modern. He doesn't think I will find an LT1 in the bunch. To find out I will need to walk through the field. He estimates an hour or so to see everything. Search continues.

BTW Software reading of the PCM now works a treat. Added a ton of failure messages (60 or so) in most places. Probably wrap this soon if I can find a test mule.

-Tom

[kur4o]

https://www.ebay.com/itm/155712778141
https://www.ebay.com/itm/225919175669

Just found that 1996 l4 pcm is what you need. Some link for reference,
It is used on gramd am , cavalier and so on.

Beware that similar case pcm is used from 93-95 and it is obd1.

[steveo]

would you like a spare 1996-1997 f body ecm?

i have one here somewhere however i never plan to do anything with it anymore, no time

i believe it is not bricked but am not 100% sure, although im sure it would be a good candidate to sacrifice for socketing, which i would highly recommend

if you are in canada like your signature suggests simply send me your address in a pm and i will have it couriered to you

[steveo]

guys i sent tom 2x obd2 lt1 ecms today so i think he's good to go. i think one was originally from kur4o and the other one i forget but it might have one side bricked

should definitely be enough hardware to abuse for testing

[Tom H]

guys i sent tom 2x obd2 lt1 ecms today so i think he's good to go. i think one was originally from kur4o and the other one i forget but it might have one side bricked

should definitely be enough hardware to abuse for testing

Thank you, Can't wait to start the testing!

-Tom

[1project2many]

Hi Tom,

Another potential source for 68HC11 OBDII ecm's is here:
https://www.ebay.com/b/Engine-Computers-for-Daewoo-Nubira/33596/bn_1362181

Daewoo used 1.8L, 2.0L, and 2.2L GM engines and electronics for a number of years. Some Isuzu vehicles also used GM engines and electronics. Here is a related thread with pictures.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?7542-99-Isuzu-3-5-anyone-know-about-these-ECUs

This video has a bunch of really great shots of a Daewoo circuit board.
https://www.youtube.com/watch?v=Z4fxmOmV464

I have a Daewoo ecm that I'd love to be able to use in an upcoming project. I'd be happy to obtain a used one for testing if you want to work on one.

[1project2many]

https://www.ebay.com/itm/155712778141
https://www.ebay.com/itm/225919175669

Just found that 1996 l4 pcm is what you need. Some link for reference,
It is used on gramd am , cavalier and so on.

Beware that similar case pcm is used from 93-95 and it is obd1.

For reference, 1995 and newer J cars (Cavalier and Sunfire) use an external ecm as pictured above. 1993-1994 J cars used an interior mounted ecm. V6 J cars from 93 and 94 actually used a 1227730.

[Tom H]

Thanks to everyone for the information + help.

I will soon have all the resources I need to do the testing. Fun part will be testing out this idea of Brick Free Technology using the EEPROM. Two loaders to be written. First (TSide) loads from the DLC using standard J1850ish commands. Second (ESide) needs to load from the SPI. Second is a bit tricky unless I can avoid working with the standard TSide support for comms with ESide.

Again, I appreciate the depth of knowledge here.

Thanks -Tom

[titanium]

16161237 Geo storm 1992 1993

[digimaster]

Thanks to everyone for the information + help.

I will soon have all the resources I need to do the testing. Fun part will be testing out this idea of Brick Free Technology using the EEPROM. Two loaders to be written. First (TSide) loads from the DLC using standard J1850ish commands. Second (ESide) needs to load from the SPI. Second is a bit tricky unless I can avoid working with the standard TSide support for comms with ESide.

Again, I appreciate the depth of knowledge here.

Thanks -Tom

what kind of reader are you using, do you read on bench (upa xhorse...etc) or you use an interface direct to the ALDL?

[titanium]

also 16142013 from a Suzuki or a Lotus

[Tom H]

what kind of reader are you using, do you read on bench (upa xhorse...etc) or you use an interface direct to the ALDL?

I have been using hardware and software of my own design for PCM access both through ALDL and OBDII. So far all this is done using a bench setup.
-Tom

[Tom H]

also 16142013 from a Suzuki or a Lotus

Thank you for your info. I had hope that some 'HC11 based designs would have been used after'96.
-Tom

[titanium]

I have been using hardware and software of my own design for PCM access both through ALDL and OBDII. So far all this is done using a bench setup.
-Tom

can you steer me on the right direction? I just need a hint to how read and write the eeprom

[Tom H]

can you steer me on the right direction? I just need a hint to how read and write the eeprom

Not sure I know enough about what you are working on to answer, but here is my best shot...

GM ECMs before 1996 use ALDL for communications to the best of my knowledge. They used EPROMs to store code/tables and whatever. The EPROMs were socketed to allow replacement of the code without replacing the whole unit. For these sort of applications you need to buy/build an EPROM programmer and use a black light to erase.

Later ECMs use a combination of ALDL and J1850 VPW --> AKA --> Class II --> AKA --> OBDII. The operations permitted on the two networks depends on the factory code. The one I have been working with permits limited upload of code through the ALDL. The OBDII also permits limited upload. To get complete access to the code, you need to download a program to memory which then gives you full upload. Somewhat confusing but this permitted GM to control who could see what.

One last way to access a 68HC11 is to use the bootstrap option. I am working on one now that gives full capability to reprogram PCMs that are bricked.

Last up, the 68HC11 contains a small EEPROM. In the factory code this stores variables such as serial number and other semi-constants. I am not aware of any of our PCMs that used EEPROM for code. The later units use FLASH. EEPROM would be an improvement form some perspectives as it would allow alteration of the stored code without re-write of all the code.

Cheers,
-Tom

[titanium]

Thanks Tom this help me a lot and this is the best response I have so far, this ecu is a 68hc11 base and I know that the way to read/write is by the aldl, but what i dont know is if the the tables are store on the 68hc11 or on a independent memory chip, if the last is the case then i can read it on my XGPRO OR ON AN XHORSE OR A UPA, is more work but is a starting point to have a bin file

[Tom H]

This ecu is a 68hc11 base and I know that the way to read/write is by the aldl, but what i dont know is if the the tables are store on the 68hc11 or on a independent memory chip, if the last is the case then i can read it on my XGPRO OR ON AN XHORSE OR A UPA, is more work but is a starting point to have a bin file


What application was this ECU for? Is it a single 'HC11? I take it that this precedes 1996/OBDII.

I am not sure what "XGPRO OR ON AN XHORSE OR A UPA" are... guessing these interface a PC to the ALDL. I built my own interface but due to limitations in the stock software, it was never much use to me other than understanding the car's network. In my case it is the ALDL that links together the PCM with antilock brakes, DERM (air bags), dash and even the radio.

There is a tiny bit of EEPROM in the 'HC11 however it will never be enough to store the necessary tables and whatnot. You probably need to open the ECM and see if there are socketed chips. In case all chips are soldered, it is probably flash based. If you see a socketed part, it's probably EPROM based. The program I am working on might be workable to give you access to read/write depending on exactly what chips are involved. In any case, you will need to dig a bit deeper to understand enough about it to work with it.

If you post a hi-res picture of the board, I might be able to identify some of the parts for you.

-Tom

[titanium]

19976
Hope the pic uploads