I have a 96 Explorer with 140,000+ miles on it. The check engine light keeps coming on but I cannot read the codes telling me what is wrong. I use a Diablo Predator to scan the codes, it always works on other vehicles without fail, but for some reason, it fails to work on this one. It will clear the CEL though. Any ideas what may be up?

 

Have you tried to unhook the battery for like overnight. I'm not saying that will cure the issue but it might be worth a shot.

 

code may not be engine related .so you may need to scan the trans which will also turn the mil on. that trans was the first electronic 5 speed unit and has been the problem child in our shop as to how badly it fails when it does.

 

Sometimes an ABS malfunction will flash the light too. Not sure about this particular year though.

 

I'm certain mine is a 4 speed, 3 speed with OD.

I'm curious though, why hook anything to the CEL if you can't scan it? I suppose I'll just have to take it to the dealership to be sure. The problem is, in my county, they just started doing inspections with an ODBII scan, and if your CEL is on, you automatically fail and I can't fix it without knowing what is triggering the CEL. So, I guess they get you coming and going nowadays. Thanks for the responses so far, any others?

 

The solution for this might be as simple as replacing a fuse.

Take a look at your wiring diagram and see which fuse the "data link connector" is wired to. If that fuse is blown you cant pull codes.

 

Allrighty, fuse #5 is for OBD. I pulled it out, looked at it, it was fine, reinstalled it, and tried tpull the codes again. It worked! So, what I have is low EGR flow. I used my Haynes manual to isolate the fault to the valve itself. So, thanks for all the replies.


Now I gotta get a new one. I hope all the bolts come out easily. Wish me luck.

 

i would coat the threads on the screws of the new valve with 'anti-seize compound' that you can buy at most auto parts stores...it is a copper based substance that will prevent the screws from becoming seized over time due to heat and or corrosion....i use it on spark plugs and lug nuts as well....works great...

 

Maybe you need a new "one" whatever the one is...I assume you mean a EGR valve.

But maybe that wont fix it. Your PCM is only telling you that it thinks the EGR flow is less than expected. Maybe you have a bad DPFE sensor that is not reading the flow correctly. Or some other issue. Try it out but remember a PCM is just a stupid computer - GIGO.

 

it could also be just a clogged EGR pipe that is restricting the flow of exhaust gases to the EGR valve.....this is very common, especially in older engines with high mileage ....

 

Yep, MrSki, I thought about it some more and also found a thread on this forum that lead me to a bad DPFE. Basically, I have ref voltage at the DPFE and no output from it going to the PCM. I also hooked up a piece of hose to the EGR valve vac port and applied a little vacuume (read, I sucked on the hose) and the engine almost died. That lead me to believe the EGR is good because that proved there wasn't any restrictions to the throttle body or from the head, and the DPFE is bad because of no voltage to the PCM. So there we have it.