94 Cutty Vert 3.4 dohc OBD scanner

[Bigdaddy000]

Ok, so I have a 12 pin connector which i assume is an OBD-1 connector. The problem seems to be it has OBD-2 codes in the LQ1 ecu.  What scanner can I purchase to read codes because it seems all the scanners today have the 16 pin OBD2 connectors? Is anyone around the Orlando area with access to a GM scanner? Any help would be greatly appreciated.

[Schurkey]

Any professional-grade scan tool capable of working with 1994 GM vehicles will readily communicate with that ECM.  I use a Snap-On "Red Brick" MTG2500 with a software cartridge new enough to handle 2006 model year vehicles.

 

Posts 14 and 15, although some of the back-story in earlier posts is kind of humorous.

http://www.automotiveforums.com/vbulletin/showthread.php?t=1146067

 

The problem is with cheap-junk "consumer-grade" scan tools, which are typically set up for partial-functionality with OBD-2, and often have no, or supremely limited functionality with OBD-1.

[Padgett]

I have several but sounds like you need a Tech-1, I do know someone over on the far east side (Oviedo) who has one but would have to have him call you.

 

Not sure what you mean by OBD-II error codes. GM ALDL (OBD-1) codes are all two digit. OBD-II are four digit. Though 95 was the only confused year or do you have a later ECU ?

[Psych0matt]

I thought 94 was weird too (I had one). Too late to use the paper clip trick but not quite obdII

[Padgett]

First thing to do is to figure out what you have. Thought you said it was a 12 pin connector and that was ALDL. See here to figure out what you have. For ALDL I mostly use an OTC 2000 scanner with a late 3-in-1 cartridge. It says copyright 1994 but never had something from that year.

 

Also have a Moates setup for my PC. And then there is all the OBD-II stuff.

 

ps yours is 8192 baud. Think the last 160 baud was in the 80's.

[RobertISaar]

Not sure what you mean by OBD-II error codes. GM ALDL (OBD-1) codes are all two digit. OBD-II are four digit. Though 95 was the only confused year or do you have a later ECU ?

 

the 94-95 LQ1 documentation uses 3 digit OBD-2 styled codes, but other than the arbitrary numbering system(which you could just relabel into 2 digit codes if you wanted to), it's an entirely OBD1 implementation.

 

I thought 94 was weird too (I had one). Too late to use the paper clip trick but not quite obdII

few 94-95 vehicles actually allowed that, it was limited almost entirely to some of the truck applications(some of which were still running C3 ECMs).

[Padgett]

OK a two digit code is 35: IAC or idle error. What is it for a '94 ?

 

C3 was the early Computer Command Control (160 baud). Looks like the only applications that survived to the '90s were leftover TBI models that had not changed. I never liked the TBI though the cross ram version was kinda neat.

[RobertISaar]

oddly enough, I don't see a DTC for 94-95 LQ1 for IAC.

[Imp558]

So those do blink codes by jumping A&B?

[Galaxie500XL]

I've got an old Actron CP-9110 I use on my Cutlass.  Cheap, but effective.  There's one currently on Ebay for $39.99.  You'd need the GM cartridge, and cable, but those are usually pretty easy to find.

 

http://www.ebay.com/itm/like/191851700916?lpid=82&chn=ps&ul_noapp=true

[Galaxie500XL]

I've got an old Actron CP-9110 I use on my Cutlass.  Cheap, but effective.  There's one currently on Ebay for $39.99.  You'd need the GM cartridge, and cable, but those are usually pretty easy to find.

 

http://www.ebay.com/itm/like/191851700916?lpid=82&chn=ps&ul_noapp=true

Mine came with a Ford and GM cartridge, I bought a Chrysler cartridge to use on a LeBaron convertible I had.

 

As a nice bonus, it works nicely with both our '93 Century wagon, and my IROC.

[Padgett]

Looks like 94-95 LQ1 uses the same commands.

 

Note: had to rename from a DS file to TXT to post.

 

 

 

A264.txt

[GOT2B GM]

Buy a knock off tech2 from aliexpress

[Bigdaddy000]

My ECU# is 16196401. The factory service manual states i get P0xxx codes. That is obd2 afaik. However i do have a 12 pin aldl connection under the dash. It has 3 pins in it. A,M and D. M afaik is not 160 baud. It's 8192 baud. here is some info for everyone. 

[Nas Escobar]

I have several but sounds like you need a Tech-1, I do know someone over on the far east side (Oviedo) who has one but would have to have him call you.

 

Not sure what you mean by OBD-II error codes. GM ALDL (OBD-1) codes are all two digit. OBD-II are four digit. Though 95 was the only confused year or do you have a later ECU ?

 

Select 94 and 95 GM vehicles are what people like to term "OBD 1.5". OBD1 computer, OBD2 codes.  The programming is the similar if not the same to 93 and below cars however they're not coded in GM's proprietary ALDL codes. They're coded in the universal OD2 codes (PXXXX). Each car was different. From what I remember, the W bodies (and the N bodies too) got the OBD2 codes but OBD1/ALDL connectors. The 95 F and Y body got the OBD2 connector, OBD2 codes, HOWEVER was fully OBD1. An OBD2 scanner won't read the computer on those cars. GM was really one strange car manufacturer during these times.

 

oddly enough, I don't see a DTC for 94-95 LQ1 for IAC.

 

I think that mostly has to do with the MAF being there. It should have a code though, I know OBD2 does have a code for the IAT.

 

So those do blink codes by jumping A&B?

 

No, 94 and 95 require a scanner (professional way to do it) or TunerPro and the corresponding cable to connect to the car's computer (usually ALDL but once again the F and Y body had that funky connector).

 

Robert Saar can explain tunerpro (I've been meaning to make a how to, probably will once I buy a new laptop or slap an SSD into my old one).

 

http://www.ebay.com/itm/GM-OBD1-Scanner-Cable-Software-Scanner-USB-to-12-pin-ALDL-direct-/361538788706?hash=item542d641d62:g:KwcAAOSwiYFXGESA&item=361538788706&vxp=mtr

 

The link above is the cable that you need to connect the car's computer to your laptop or tablet (which I recommend laptop. A tablet may not be spec'ed good enough to run TunerPro).

[Padgett]

OK, would need to play with one but looks like the data points are ALDL but error codes are returned in OBD-II format.

 

Just looked at the data stream and for my 93, the Malfunction Flags are in data words 3-6 with 8 flags (bits) in each one. For example the TPS signal low is code 22 and the flag is in word 3 bit 2.

 

94-95 uses similar flags just a lot more so the flags are in words 49-64  and TPS signal low is word 50 bit 7 (history) and word 58 bit 7 (current) and is now interpreted as P0122 instead of code 22. Note that the flags mean the same thing - the TSP signal is Low. Just is interpreted differently.

 

Also the original ALDL only had one location for each code, OBD-II has two: history and current.

 

Both return coolant temp as a byte value  DEG C = .75N - 40 but from different locations. Mode 1 word 7 for 93. Mode 1 word 3 for 94.

 

Before OBD-II you had to know the year, make, and engine to know which data stream to use. OBD-II standardized locations and values which is why current devices are much simpler and less expensive. The good news is that the different data streams are now OBD-II compliant. At least for standard values.

 

The difugledy is that every manufacturer has proprietary code extensions that are not well known. Coolant temperature is a standard value. Oil pressure is not. My Jeep can display oil pressure, oil temperature, and transmission oil temperature on the dash. Torque Pro cannot unless you know the proprietary PIDs.

 

Could go on for a while but suspect eyes are already glazing over. Can say that next to the triple and quad redundant flight control computers for an F-16 particularly terrain following "hard ride", this stuff is easy.

[Bigdaddy000]

Let me ask....does anyone know if the Actron cp9690 will work on this car? Its supposed to do OBD1 in addition to OBD2. I just do not want to spend 200.00 on a unit i cant return if it doesn't work for me.

[55trucker]

http://www.zentiz.com/actron-cp9690-trilingual-obd-iobd-ii-elite-autoscanner-pro-kit-review/

 

don't see why not....

 

not familiar with the item.

[Padgett]

Differences between 91-93 LQ1 (ALDL) and 94-95 (ODB 1.5) can be seen by downloading $2E and $DF files from Tunerpro and examine with notepad. ALDLstuff.zip has nearly every ALDL definition in an easier to read format. If you cannot find pm and  I can send a copy. A decade ago everything was online but much has scattered today.

[Bigdaddy000]

Just got back from OReillys and they use the Bosch obd1300 which is the Actron CP9690. IT WORKS.  .  NO codes though.  wtf?  . Going to Tranny shop for a bit of diagnosis.

[Padgett]

May have only been looking for engine codes. Have to go out but when I get back will look at my 4T60E files.