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CCCUK » C4 Generation » OBD connector ? 1 or 2

#1: OBD connector ? 1 or 2 Author: Coltstingray Location: Stoke on trent Post Posted: Today at

Hi everyone Iím new on here Iím due to pick up my new baby soon a red 1989 C4 any day now canít wait. Not sure if this has been answered before I tried searching couldnít seem to find it.
I want to buy a OBD scanner and Iím having some trouble some websites on eBay or amazon say that there OBD 2 scanner works on a 1989 Vet but others say itís OBD 1 only that works, has anyone used a scanner on a C4 my year? and if so where can I get on

Thanks in Advance

Carlton

#2: Re: OBD connector ? 1 or 2 Author: gary 53 Location: benfleet Post Posted: Today at

it will be OBD 1

#3: Re: OBD connector ? 1 or 2 Author: Coltstingray Location: Stoke on trent Post Posted: Today at

Thanks have you used one ? And would you be able recommend a certain one

#4: Re: OBD connector ? 1 or 2 Author: gary 53 Location: benfleet Post Posted: Today at

You need TECH 1 OR 2
I have never used one here's a link
will tell you how to recover codes

https://corvettephotographs.com/c4vettes/ecm.htm

#5: Re: OBD connector ? 1 or 2 Author: Coltstingray Location: Stoke on trent Post Posted: Today at

Thank you appreciate it

#6: Re: OBD connector ? 1 or 2 Author: leanmeanvettemachine Location: Norfolk Post Posted: Today at

Coltstingray wrote (View Post):Hi everyone Iím new on here Iím due to pick up my new baby soon a red 1989 C4 any day now canít wait. Not sure if this has been answered before I tried searching couldnít seem to find it.
I want to buy a OBD scanner and Iím having some trouble some websites on eBay or amazon say that there OBD 2 scanner works on a 1989 Vet but others say itís OBD 1 only that works, has anyone used a scanner on a C4 my year? and if so where can I get on

Thanks in Advance

Carlton


Hi Carlton,

Another idea if you need to know what the fault is but don't necessarily want to purchase a scan tool to find out, is to use the paper clip trick (explained here). With the ignition off, place a paper-clip between pins A & B of the 12-pin ALDL connector under the dash Image.

Turn the ignition on without starting the engine. Then get ready to count the flashes of the MIL (check-engine light). Sequences will be of the form "FLASH, FLASH pause FLASH, FLASH, FLASH". These flashes correspond to the two-digit diagnostic fault code, i.e. this example is code# 23. Troublecodes.net has a table of GM specific fault codes you can use to lookup the fault.

Once you've diagnosed the fault, turn off the ignition, and remove the paper clip. You can then clear the fault code by disconnecting the battery for more than 20 seconds.

TL;DR - The old ALDL diagnostics bus had a facility to flash the MIL (check-engine light). If you count the flashes you can diagnose the fault without a scan tool.

Hope this helps,
Alex

#7: Re: OBD connector ? 1 or 2 Author: Coltstingray Location: Stoke on trent Post Posted: Today at

Thanks for that I have tried to find mine canít locate it is it drivers side or passenger side? Or is it connected to something I have to unplug?
Cause itís not hanging down in there

#8:  Author: dm575 Location: Midlands Post Posted: Today at

On my 91 the connector was tucked away under the dash. Remove the kick panel and take a look, it will be there somewhere Smile ( driver side to the right of the steering wheel )

Last edited by dm575 on Thu 22 Feb 18 20:57; edited 1 time in total. [17 %]

#9: Re: OBD connector ? 1 or 2 Author: Redlevel Post Posted: Today at

Coltstingray wrote (View Post):Thanks for that I have tried to find mine canít locate it is it drivers side or passenger side? Or is it connected to something I have to unplug?
Cause itís not hanging down in there


It's above and slightly forward of your right knee on the drivers side usually covered with a black plastic cap, just under the bottom of the dash but easily accessible.

If you have SES on the screen, don't panic or try to diagnose the codes right away as they are sometimes only symptoms and not actual faults.

Drive the car a good few miles, get it hot and idling nicely, then switch off, disconnect the battery, reconnect and see if the SES comes back, if it does, do the paper clip test and read what you've got. Corvettes do not like being idle for long periods and may well throw up codes after a long lay up just to p*ss you off. If the car drives fine even with codes don't fret as most codes are easily dealt with and are no real warning of impending doom! Yes

Good luck and keep us posted..
CCCUK » C4 Generation » OBD connector ? 1 or 2


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