1995 Tacoma

Good morning Can anyone advise on a brand and model of code reader that will link to my 1995 Tacoma 2.7l . It has the OBD 2 port and I have tried three different readers and a laptop but they will not connect. They all power up so I believe it has power to the port but will not link. Thanks

 

I believe the 1995 has both connectors, can you do the pin method with the old connector under the hood?

https://www.2carpros.com/articles/t...finitions-and-code-gathering-method-1990-1995

https://www.youtube.com/watch?v=ud7y3KvU-Mo

 

I tried jumping the pins on the diagnostic port under the hood with no luck getting flash codes. The more I read on Tacoma's I find that the jumper trick wont work on the 95 or 95.5

 

I had no problem with any reader on my 95.5 truck. It's technically fully OBDII compatible. I'd look to make sure all the wires on the back of the connector are firmly connected and not split. It's easy to bump that area with a foot and break something. It only uses like 4-6 wires total. The communication protocol is ISO 9141, one of the earliest protocols, so every OBD II reader no matter the age should be able to communicate.

 

Quite Possible the pins on the truck side are just corroded .

impossible to see with the naked eye most times

I get this problem quite often when seeing the vehicle for the first time.

 

Okay. I will check the wires and pins to confirm. I will clean and add a touch of dielectric grease and report back

 

Dielectric grease does not conduct electric !!

 

Had a close look. 4 wires total. Sprayed with electrical contact cleaner and lightly cleaned with a dental tool , re sprayed . Performance tool scanner W2977 powers up but will not link.

 

And you truck key in in the ON position?

 

correct key is on .. Scan tool goes thru the process but will not link Shows scan KPW 2000 then ISO9141 but then error codes will not link

 

May have a bad wire or a broken contact. I'd try testing the OBD port wires for continuity

 

Okay. I will have a look . I Dont have a wiring schematic but can check the plug wire colors and go back to the ECU. I will have to find the ECU first.

 

It's above the glove box, there's a piece of plastic you can unscrew to get to it

 

Ya I found it. The OBD plug has a brown, purple, white with a grey dot and a white with a black stripe .. I found the white with the grey dot , several brown but no white with a black stripe or a purple..

 

I have continuity on the white with the dot and the brown. Cant find a purple or the white with a black stripe. Tried the purple with the red stripe and a purple with a white stripe. no go

 

I assume one is power and the other is ground

 

There's a power and a ground and I believe two serial data lines

 

Purple is power. White with black doesnt have continuity to ground

 

Only one wire (the white shielded signal wire) goes to ECU the rest is power and ground.




Make sure the shield is grounded too.

 

Okay. From what I can tell the problem must be a possible bad ground for the brown and the white/ Black wires. Where is that ground located?