CEL without a code, and cruise still doesn't work...

[motopsycho650]

I am wondering what you guys would check first, second, etc...

My '94 has a check engine light that comes on every time about 5-10 seconds after I start it. When I do either KOEO or KOER tests, the light turns off, and flashes the normal 111 code. There are no codes stored in memory.

I've had this vehicle about a month, and it's always had a CEL. At first I was getting codes, and I have solved those issues, one by one. My point here being, I believe the PCM and the check engine circut are working correctly.

The only other thing I have not working is the cruise control. Is there a possible common link? What parts of the cruise control circut does the PCM watch?

 

[SPORTEXP]

If the light comes during cranking and stays on for a short while after engine starts, this is what they call the bulb check so you know the light bulb for the CEL is working and not burned out.

 

[MrShorty]

The common sensors that the cruise and PCM watch are the brake on/off (BOO) switch/sensor on the brake pedal and the vehicle speed sensor (VSS).

Does the CEL come on and stay on? I might also check the keep alive memory KAM power circuit to make sure the PCM isn't losing codes everytime you turn the key off.

 

[motopsycho650]

If the light comes during cranking and stays on for a short while after engine starts, this is what they call the bulb check so you know the light bulb for the CEL is working and not burned out.

Yes, I know that is normal. When the engine starts, the light goes out, and somewhere between 5-15 seconds after the engine has been running, the CEL light comes back on.

I have had it hooked up to two different readers. One, a cheap code flasher, and the other was a Snap On scanner. Neither of then were able to see a code. Both send back a 111, everything normal code.

Here is the weirdest part. I'll start the engine and leave it running, the CEL will come on and stay on. I hook up a flasher and perform the test without ever turning off the engine (the PCM has never lost power since it turned on the CEL). As soon as the testing starts, the CEL turns off, flashes 111, and stays off until I unhook the scan tool, or the next time I start the vehicle.

 

[motopsycho650]

The common sensors that the cruise and PCM watch are the brake on/off (BOO) switch/sensor on the brake pedal and the vehicle speed sensor (VSS).

Does the CEL come on and stay on? I might also check the keep alive memory KAM power circuit to make sure the PCM isn't losing codes everytime you turn the key off.

I know the BOO is working. I have no reason to think the VSS is not working.

Yes, after the check engine light comes on, it stays on until I shut off the engine. I will look into the memory circuit. None of the previous codes I got were ever saved in memory.

I bought this '94 explorer for 200 bucks because it had a blown automatic tranny. Otherwise, it was in much better condition, with half the miles of my old '92. I swapped the re-built tranny I had in my '92 into this '94.

The '94 has always had a CEL, but originally I did get codes. 1st was the Neutral Safety Switch, easily fixed while swapping tranny's. The other code was the Delta Pressure Flow Sensor in the EGR system. I installed a new sensor & hoses, and that code went away.

Besides tearing apart the dash and physically tracing different wires, I'm out of ideas on where to go. The Memory circuit seems like a good place to start, as well as swapping cruise control amplifiers.

 

[MrShorty]

As soon as the testing starts, the CEL turns off, flashes 111, and stays off until I unhook the scan tool, or the next time I start the vehicle.

How long are you letting the test run? Do you ever get the "goose" pulse? The initial three flashes during the KOER test are the engine id code: three flashes means 6 cylinders. The actual test may take a couple of minutes before the computer output the KOER codes. You might review the test protocol (see my "notes on pulling EEC-IV codes" in the EEC-IV forum) to make sure you are following the protocol correctly.

 

[motopsycho650]

How long are you letting the test run? Do you ever get the "goose" pulse? The initial three flashes during the KOER test are the engine id code: three flashes means 6 cylinders. The actual test may take a couple of minutes before the computer output the KOER codes. You might review the test protocol (see my "notes on pulling EEC-IV codes" in the EEC-IV forum) to make sure you are following the protocol correctly.

Yes, it does the engine ID code, then it does a long pause, then it displays the 111 code. If there were any memory codes, it's suppose to pause again, and then flash those, but I just get a repeat of the 111 code. Also, there is a difference between the "3" engine ID code (3 quick flashes), and the 111 code, (three flashes with a short pause between each one).

 

[motopsycho650]

I just hooked up the Snap On scanner again last night after work. did the KOEO test, got nothing. Warmed up the engine, and them did a KOER test. The cool thing about the snap on scanner is that it's not a flasher. It actually displays any codes on the screen along with a description of the code. Again, I got nothing from either test except a 111 system normal code.

No one has ever had a similar problem?

I just passed emissions here in CO, so it can't be that big of deal. Also, I drove 100 miles on the highway over the weekend and got a little over 18 MPG. Again, it can't be that big of a problem.

I am getting tired of thinking about this. I'm thinking I'm going to go solve my CEL by covering it with some electrical tape, or removing the bulb.

 

[boggs1227]

if i'm not mistaken i think in the koer test there is a "shake" test ... it lets you to goto each sensor and move it and if a bad connection is found the tester or the pcm will let you know you hit the right problem sensor .

....or at least something to that effect about the test ...maybe someone else that has performed this type of test can chime in and give their thoughts.

or just could be a semi-faulty computer ??

or if you can't figure out what the hell is happening then you could remove the bulb and hook that lead up to a relay and run that to some day time running lights .....they would come automaticlly then

 

[motopsycho650]

I got a code finally. It was about 2 weeks ago, but I hadn't been back on here.

I ended up locating and un-plugging the PCM. Then, plugged it back in, ran it untill the CEL came back on, and finally I got a code. it's saying the cam position sensor is bad. Just for fun, I unplugged the cam position sensor, and I got no change in anything. I am taking that to mean the sensor is dead. Unfortunately, it's 300 dollars as a new part. ouch.