Need some help interpreting codes on my 97

[glfredrick]

I recently had opportunity to use a Snap On Color Graphing Scanner for the weekend and tried to run the codes on my 97 4.0 SOHC/auto/4x4.

The scanner came up with this code when I did a KOEO test.

"P1000 OBDII System Checks Incomplete"

It refused to check the computer - even after I cleared the codes and tried again.

When I tried the KOEO test, the scanner just went crazy and didn't read anything.

I recorded a few drivability parameters if they mean anything that helps...

TA (v) 1.04
Load % 28
ECT (v) 8.6
Bard (K/v) 101
Bard (Hz) 158
ECT (*c) 79
IAC 0
IAT (v) 2.68
IAT (*c) 27
02511 (Mv) 1
o252 (Mv) 27
Open

We are having drivability issues that involve the GEM module (t-case acts weird and "locks up" at times) - dash lights don't work when the headlights are on (the warning lights like the "blinking" OD light - 4x4 light, etc. - not the illumination lights) - poor fuel milage - check engine light often comes on - and stays on, etc.

Any ideas are appreciated.

 

[dreamr]

Don't know if this will help, but here is my .02

The code you listed I get on mine whenever I do not drive for a full test cycle (100 miles) since I last cleared my codes or reflashed the EEC.

If it is your GEM that is acting up it would likely not offer a code that could be read by a standard OBDII scanner. It has to be read by a unit able to communicate with the GEM through the EEC. Try a tranny shop or such.

A final thought. When I was searching for my 4x4 issues I found that there is a TSB regarding the GEM in the 96, 97 model years. The symptoms are very similar to what you describe. This was corrected by a re flash of the EEC by Ford

 

[dreamr]

A note.....
I had a aquaintance at a local shop scan using that snap-on same scan tool, and he was unable to scan the GEM. I thought it would do it for sure, but nope.

 

[glfredrick]

A note.....
I had a aquaintance at a local shop scan using that snap-on same scan tool, and he was unable to scan the GEM. I thought it would do it for sure, but nope.

Thanks - I'll move up to the next level. Since I'm now a dealer, I can just grab a MODIS tool and run the truck through that. The truck should scan with the color graphing scanner though. It is not just a simple code reader, the one I used had the full troubleshooting package installed, and I could turn on accessories, etc., through the tool.

Also, I did not reset the codes before the first scan - which is what is confusing me.

I know about the GEM reflash - and have already had 2 different GEM modules installed on my truck. They were both on the dealer - but the next one comes out of my pocket...

Can you say CHEVY? :fire: