I have a 1995 Chevy S10 Blazer 4X4 with a little less than 96K miles on it.


VIN # 1GNDT13W2SK216235


When I bought it from the original owner, (who just happens to be a Baptist Church Pastor), it had 58K miles on it. He had added a 'Flow Master Exhaust system, K&N Air Filter, a Pioneer 12-CD Changer, and tubular side step-rails. He had obviously taken excellent care of it!! When I bought it, he had just finished 'Armoralling' the interior panels and tires!!!


The only maintenance needed/required on it in the last 10 years, other than standard oil change and coolant change, has been:

1. Transmission Rebuild in 2005
2. EGR Valve replacement 2007
3. Brakes front/back 2007
4. Battery replacement 1999, again in 2006.
5. Alternator replacement in 2006



I have done most of the maintenance and repairs on my vehicles for over 50 years...(with the exception of automatic transmission work). The automotive industry has now made it almost impossible to do maintenance on your own car now though. There are too many sensors and extraneous BS items that do not need to be computer-controlled. But, thanks to Government regulations, we have no choice.

I am 66 years old and have eye-sight problems along with arthritis, but If I can do something myself, you bet your sweet *** I'm gonna do it!!

Back to my info request..........

My Blazer has started to throw codes up for "Service Engine Soon" light.
So, I take it to my nearest Autozone and get them to do a free scan and obtain the code representing the source of the problem. Most recently a problem with the EGR. I replaced the EGR and everything was back to normal.
Should any of you that do your own repair work, and have an EGR problem, I would suggest buying the EGR valve gasket that has a screen incorporated into it to trap carbon deposits before they are allowed to obstruct the valve operation!! It's about $12.

Anyway, I got tired of going to Autozone and getting them to do a scan, so I decided to buy my own scan code reader. Here is where it gets interesting.....
The sticker under the hood says 'OBD-I Compliant'. Yet the connector under the dash is a 16 Pin connector which is for OBD-II, for 1996 and above models.

I decided to purchase a scanner to read the stored codes in the computer's memory. I bought a relatively comprehensive scanner on fleabay for $71 with shipping.
TOPTAK, Model OT-680CAN. It supports all 5 Protocols for OBD-II,
ISO-9141, KWP2000, VPM, PWM, and CAN Bus.

It won't even communicate with my ECM/PCM. I can't read Sh*t!!

I can't get squat for information from my local Chevy Dealer, other than "Bring it in, we will fix it"!!!
Here is the Pin Out on my Blazer's under-dash connector:

Pins 2,4,5,9,13,16 are present in the connector

Pin 2......Busline + of SAE J1850 Protocol
Pin 4......Chassis Ground
Pin 5......Signal Ground
Pin 9......Discretionary.....?
Pin 13....Discretionary.....?
Pin 16....Unswitched Battery Positive

Rather than trash my new scanner, I would like to see if I could make an adapter to interface with my connector to block certain pins, or tie a couple of pins together in an adapter to make this scanner work. It's either down to the choice of selling my 'New Toy' to a 1996 or later vehicle owner, and buying the Actron Model# CP9175 that Autozone uses to read the codes from my '95 Blazer abortion connector!! They have them on Fleabay for under $110.

Anyone have any helpful ideas on my connector Pinout??
Anyone put a Signal name on the 'Discretionary' pins??

Or tell me exactly what kind of an abortion I have ??

Oh, to complicate things even more……….I looked at the ECU/ECM/VPM/PCM, whatever the nomenclature is. It is mounted above the passenger-side fenderwell beneath the hood. The UPC label says : Factory Authorized Remanufacured Unit for DELCO Electronics.
SVC# 16193495
‘86BABBK25022647ZA’.
I can’t find these numbers from DELCO !!

Also……….my ABS light just came on (again). My brakes are good…front disc pads replaced 2 years ago, rear Shoes replaced 2 years ago. This light has come on and eventually disappeared by itself 2 times in the last 3 years. It has been on for about a week now. I was under the impression that the speed sensor and the ABS system worked in conjunction with each other. I disconnected the Positive Bat. cable and left it off for 1 hour. I thought this would turn it off if it's stored in temporary storage, and does not turn on the ‘Service Engine Soon’ light. But that did not work.
I am getting frustrated as hell!!!

 

Do you have +12V on pin 16? If not, check your CIG fuse. It powers the DLC on the later models. I do not have a schematic in front of me to verify the same on your 95. But if this is not powered, then the scan tool will not see the vehicle.

If your PCM is on the passenger fender under the hood, it is OBD2 compliant. Strange that the emissions sticker states OBD1...

 

Thanks for the reply swartlkk......I checked pin 16 as suggested and +12V is there. I also checked pins 9 and 13. they were both at ~ +5 V, which would indicate a 'logic voltage'. I wish I knew what these two pins are.

 

Got this from troublecodes.net







12 Pin DLC


Does this help?

 

That is the OBD1 DLC.

 

DOH! Retarded.

 

I appreciate everyone's response. If anyone else is here because of the same situation I have, I found my solution.

I bought a NEW Actron CP 9145 Auto Scanner on Ebay for $79 USD.

It has an awesome "Set-up" function built in. Vehicle, Year, model, etc.

It covers all OBD-2 vehicles from 1996 up to 2006 (The date the EPROM was burned), as well as 1994 OBD-1 vehicles.

I was ready to send it back after I went through "Set-Up".

I selected OBD-1, 1995 GM, 4X4 T-Series in the set-up. It would not communicate with the computer.

Just for the hell of it I selected "OBD-2 Global" on the second 'Set-up' attempt. It read the computer just fine!!.

It seems my abortion of a 95 Chevy S-10 Blazer with the 16 pin DLC is readable after all!! Thanks to everyone who contributed ideas, and ............"WRITE This Down for future reference"

 

Thanks!

I am trying to transplant a 95 win "W" VCM A (sideways sparkplug wires) into a 85 toyota 4runner and am in need of a diagnostic tool to get ready for smog inspection.I also ran into your very problem a couple months ago. Thank you for the home work!!

Duane

 

I have this PCM setup in my 95 Blazer ZR2 4x4 auto also. My PCM is 16193495 and as far as I've seen there hasn't been anyone quite stepping up to define the interface to this hybrid obd 1 thing.
I've read of a few scan tools that can actually do it, most often mentionned the ac9145 and the tech 1/2 with special cables.
I have a usb/aldl/16-pin cable from reddevilriver with the usb port drivers and I've been trying vaious software from tunerpro and moats and am down to realterm just to try to connect but am still having no luck.

Anyone have any definitive answers as to how to just get the MIL codes out of this thing with software and an appropriate cable. I also have tried obdcom with their cable but I know that won't work with this obd (1.5 sic) pcm.

Argh. (this is a long, no-start, sitigation).

This is the best explanation I've found as to how to talk to this pcm.

http://www.gmforum.com/1992-1999-91/...k-here-260037/

 

That's good info thanks.