Improving our dataloggers, requires your ECU ID

[BlackStealth]

Update: I simulated 20 automatic transmission computer IDs through educated guesses for the MUT2 scantool, and decoded their additional transmission error codes, and subtle differences. I just plugged in the 98 3000GT SL Automatic computer in a few minutes ago and looked at the computer ID -- it happens to be the second last one I decoded (F025). Perhaps the last ID (F026) is for the SOHC? I don't know.

Next I will work on the 98 3000GT SL SRS computer. And then 95 3000GT SL ABS computer.

[BlackStealth]

Today I wired up the 1998 3000GT SL SRS computer, noted the new computer ID, new baud rate, and a few new error codes. After I built my simulated SRS computer to unlock everything, I randomly found 27 other SRS computers and decoded those as well, noting the small differences between them. So I think I have all the SRS computers for our cars supported.

[BlackStealth]

Yesterday evening I tried browsing for some other slow baud rate SRS computers, the MUT2 scantool hangs up when I gave an invalid ID, requiring me to power down and power up. I did this about 3 times and decided not to go any further, as I don't want to subject the scantool with so many power ups in a short time span.

I did some research and it seems the 91-97 climate control computers are all the same despite the revisions (or improved models) and communicate the same. I had a few spare climate controls here to test that theory out, they all report back as the same computer ID. The service manual says the 98-99 climate control computers have two extra error codes than what I have decoded, so I went exploring. I sequentially searched 255 possible combinations and found 2 additional computer IDs that connected to the scantool. I'll go investigate those now and note the differences. Perhaps one belongs to the 98/99 climate control computer. After that jobs is done, I'll go test out the latest ECU computer ID contribution.

New addition: E620 96 3000GT DOHC Spyder SL (Source: Thank you DuTTch)

[BlackStealth]

Update: I manually scanned all OBD1 interfaces from computer ID E000 to E0FF and found 11 new computer IDs that support 6 cylinders. Of these 6 matched perfectly to existing information for 91-92 3S vehicles. Some had VICS support (DOHC), some had none. None of them had Turbo related functions or tests ( Muffler change over, Fuel pump low/high test). Maybe I'll scan E100 to E1FF next.

Building an Mitsubishi OBD2 emulator took a few days to build from scratch, and then I remember I already did this project a few years back, duh. Well at least I did it in half the time, now that I have some better spying tools available.

To my surprise, the E620 (1996 Spyder SL) was different (91-93,94-95,98-99), specifically these tests:
MAF Reset Signal, PSP Switch, PNP Switch, IGN. Adjustment signal, Elect. Load switch, TPS Idle switch, A/C Switch, A/C Relay, VICS MRS circuit.

Also, Japanese and Euro computer ECU IDs won't work with the MUT II cartridge that I have here. Apparently I need a Jap or Euro cartridge like this: I tried bidding on them, but failed to win it on ebay.

[BlackStealth]

Today I hooked up Melbowski's 1996 ABS computer to the scanner, and discovered it shares the same wire (OBD2 connector pin 7) as the MFI or ECU computer -- they both share the same bus. I looked at the 99 manual and it also is connected in the same manner. This is cool, as I can support the 96-99 ABS computer through the existing hardware found on the LCDBC. I can write some software on the LCDBC that will ask for the 97-99 ABS computer ID -- pretty cool.

I noticed Evoscan software supports ABS, but everything is all wrong for the 3S except for clearing the ABS code. Well I didn't verify what Evoscan uses for Actuators tests, that may or may not be the same.

[BlackStealth]

Update: 1996 and newer ABS computers shares the same bus as the ECU, so anyone that wants to view ABS stuff can do so now on the latest LCDBC software.

1991-1995 ABS computers I did some more tests today with the nice weather, and I have learned something new. FWD ABS computers have "rear solenoid+valve test" available whereas AWD ABS computers do not. I have extracted the hex codes to turn on these tests, and clear ABS codes. Next I have to build the LCDBC addon, so it can run the super slow baud rates and pretend to be an ABS computer so I can extract the remaining ABS error codes.

A few weeks ago I made a circuit for the LCDBC so I can pretend to be a scantool for the 1998 SRS computer and it worked flawlessly. For older SRS units, they have really slow UART baud rates, and the add-on for the LCDBC will take care of that.

[BlackStealth]

E6A2 94-95 3S Fed Turbo MD192589 (Source: Gatecrasher)
E6A4 97-00 GTO turbo New Zealand MD355167 (Source: Paolo)
E6AD 98 3000GT turbo MD347250

When I looked at this chart above, I decided to look at the gap between E6A4 through E6AD, and simulated those IDs to see what would happen. I found three turbo 3S vehicles HEX IDs.

E6A5 Both MUT over OBD2, and MUT mode. Two O2 sensors, Yes to EGR sensor. No MDP sensor.
E6A6 MUT over OBD2 only. Four O2 sensors, and MDP sensor. No EGR.
E6A8 Both MUT over OBD2, and MUT mode. Four O2 sensors, and MDP sensor. No EGR. Identical to E6A6 except it can communicate in two protocols.

The rom cartridge I have here does not do Euro or JDM ECU HEX IDs, my guess the cartridge only does USA / Canada vehicles only. So it is very likely the HEX IDs I've found are the missing 96-97 turbos in USA / Canada. One thing I have observed is that the 1996 Non-turbo DOHC ECU (E620) only communicates in "MUT over OBD2 mode", and not the super fast MUT mode. E6A6 is in the same boat, no fast MUT mode either, so my guess is that this is the 1996 Turbo ECU Hex ID.

[BlackStealth]

I spent two days searching for more 3S ECU Hex ID using educated random guesses.

E613 94-95? 100% 3S, "electrical load switch" missing, California SOHC?
E614 94-95? 100% 3S, "electrical load switch" missing, Federal SOHC?
E616 94-95? 100% 3S, Federal, one O2 sensor, DOHC VICS
E61A 94-95? 100% 3S, California, two O2 sensors (one for rear cat), DOHC VICS
E65F 98? 100% 3S, DOHC VICS

ETACS ECU nothing to decode at all, it generates a 90ms pulse each time you press a heater button, open door, close door, insert key into ignition, etc.

Cruise Control ECU: Decoded input checks, and error codes.

To do:
Decode 1996+ ABS error codes (13 computers).
Decode 1991-1995 ABS.

Decode SRS error codes (29 computers)

Summary:
ATX: done
ETACS: done
Cruise: done
ECS: done
Auto A/C: done
SRS: work to do.
ABS: still have to build circuit for 91-95 ABS computer

[BlackStealth]

Okay, was sick for a while, but I've recovered and resuming this project again. I finally figured out how to get my bench ABS ECU to spit out error codes. The ABS ECU is very finicky in that you must have the scantool ready BEFORE you power up the ABS ECU. None of the other ECUs behave like this. And this also explains why I could not retrieve ABS error codes on my own car, the car was running when I tried to pull codes. Mystery #1 solved. When I look at the oscilloscope captured waveforms, the DTC scan request is transmitted in serial format, and then retrieves the error code not in serial format, but in a series of long pulses, short pulses (exactly like how you would with a volt meter or light bulb to pull codes). So this explains Mystery #2, why none of my fake serial error codes did nothing.

Looking at the waveform, you can see that when it communicates in serial mode it uses approx 6v to 12v waveforms, and then in non-serial mode 0v to 6v. Now I have to re-design my electrical circuits as I didn't expect that.

[BlackStealth]

Update:

I finally have a 100% working prototype Add-On for the LCDBC. What it does is allows the LCDBC to communicate to all 8 computers on our cars, to read error codes, clear error codes, read diagnostic data, and also perform diagnostic tests. The second phase is to make a touchscreen interface for non-LCDBC users, I'm scrapping my previous prototype design and starting over because previous version is too hard to manufacture.