Code reading

Sierragirl · November 8, 2003

I have a 1990 K1500 Sierra and the check engine light keeps coming on. I'm wondering if I can get the codes read for this year model, And if so, where is the hook up??

builderpaul · November 8, 2003

Hi,

1990 is OBD1 and pretty easy to access with out any fancy scan tools. You just need to jump the A and B terminal of the ALDL, with the ignition on but engine not running. Your service engine light will flash a code 12 (one flash pause 2 flashes) 3 times than it will flash any trouble codes. When it is done it will flash the 12 again.

Post any codes and we can help.

Your ALDL is under the dash on the drivers side near the steering colume. A and B are next to each other on the upper row, right side. I don't know how to post pictures but you can probuly locate all this info with a goggle serch.

To clear codes disconnect the battery.

MCourson · November 8, 2003

Heres a pic. All I do is jump the 2 with a paper clip.

Wingnut · November 9, 2003

Or....You could just take it to Auto-Zone, Checker, Parts-plus, or whatever local parts store you are fond of, and they will usually hook up, and scan it for free.

Just my .02