CEL Coming on and Turning Off

[drumnerd33]

Re: CEL Coming on and Turning Off

Yes that looks correct

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[nitrofarm]

Sooooooo after reading this entire thread I'm still thoroughly confused. Engine running yes or no? My sons Festy is acting up and I want to check the codes.....

[drumnerd33]

Re: CEL Coming on and Turning Off

Well has anyone ever tried it with the car not running? Cuz all the info out there says engine not running? So your guess is as good as mine... Xfe71 is saying that the ecm doesn't hold the codes but that doesn't make any sense to me, considering all the info on our car says otherwise. Somebody should try it and then everyone would know.

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[Prafeston]

Is sure seems like you can check the codes after the engine is off. I'm gonna try it again hopefully tonight.

[Movin]

The sparking happens when you ground the rpm test connector and when you get a good connection it kills the engine. The correct wire
has a black connector. Some Ford and professional manuals have this information incorrect. Snap on scanners will hook up and if you follow their directions your scanner will smoke when you try to retrieve codes. They have never fixed their directions ..Even ford was losing star testers because of this. It does nothing to the car either way, one kills the engine if it is running, one initiates self test input.

Self test out put can be read with a analogue meter or digital or low current test light under the hood at the 6 pin connector. Just stick your head inside the car and read the flashes of the check engine light, its ground circuit is the sto circuit.

The battery connection to the ECM will keep stored codes with the car off.
The ECM we have makes no difference if you pull the codes with engine running or not.
Carbed cars have more codes possible than EFI. California adds some extra stuff.

In this case burn the manuals, give Aldata and their 70 gigs of data and mitchel with their 6 to 7 gigs
off data a virus! Go ground the single black connector and check your codes!

[Prafeston]

Right on! Thanks for the info Movin! Rep!

[drumnerd33]

Re: CEL Coming on and Turning Off

Very good info:thumbup:

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[nitrofarm]

Right on! Thanks for the info Movin! Rep!

Yes ! And thanks for not speaking in acronym's. :thumbs_up:

[Prafeston]

Yes ! And thanks for not speaking in acronym's. :thumbs_up:

Really! When I hear STI I just think Subaru!

By the way, I found the black single connector last night. Drove the car a bit, but I don't think I was in it long enough to trip the CEL. I'll try again tonight.

[XFSE71]

This is the wire I tried grounding a few days ago and was sparking from the ground side while the engine was running. Looks to be the right one. Single plug. Yellow w/ green line.

NO! NO! THE BLACK CONNECTOR! THE BLACK ONE!

there should be no sparks. the eca will flash codes on the MIL either running or off. engine off codes are only hard faults (something unplugged). the eca cannot report lack of o2 switch or vaf out of range because that ain't broke. I leave a green jumper wire on the black connector and ground it running or off with no sparks only a blinking little light on the dash. try it on the black connector, please. it will work.

[Prafeston]

NO! NO! THE BLACK CONNECTOR! THE BLACK ONE!

Yeah, I've established that now.

[XFSE71]

The sparking happens when you ground the rpm test connector and when you get a good connection it kills the engine. The correct wire
has a black connector....The battery connection to the ECM will keep stored codes with the car off.
The ECM we have makes no difference if you pull the codes with engine running or not. .....Go ground the single black connector and check your codes!

Yes, the black connector not the white one. Looking at the codes (9 total) for my '93 EFI, some are KOEO (a Ford term used to describe Key On Engine Off) some are KOER (another a Ford term used to describe Key On Engine Running) some are both. Code 15 & Code 17 O2 LOW or DOES NOT CHANGE = KOER. Once the key is turned off the ECA will forget the code until the condition occurs again, running, not stored in Non-Volitile memory.

You are driving down the road ... MIL comes on ... keep driving or pull over either way ... light goes out ... drive on .... light comes back on ... goes out again. Shut the engine off ... ground the black connector ... NO CODES. Why? Did the car fix itself? NO - Where is the code? gone. When you were driving the o2 sensor saw either a lean condition or a rich condition and did not switch as expected by the ECA algorithm. When you let off the accelerator the o2 started switching again so the light was turned off by the ECA because the fault no longer exsists. The code either 15 or 17 is still in Volitile Memory (RAM) and will be cleared when the key is turned off. You can pull this code only before the key is turned off. This is where we get the mystery "flashing CEL while driving". Not to be confused with OBDII Misfire Monitor reporting a Type "A" Misfire. We don't have OBDII on Festiva. We have OBDI. So as the "lack of o2 switch" comes on at steady speed and goes away because you let it idle. At idle the o2 switches, no problem, no light needed. This is a signal from the ECA that you are not going to get as good of mileage as you could be getting if you were to correct the condition. By the way Fords do not have a CEL (Check Engine Light) they all have an MIL (Malfunction Indicator Lamp) minor difference as mandated by CARB (California Air Resource Board).

[Prafeston]

Call it what you want...it's a light...that looks like an Engine and says Check under it...Check Engine Light sounds fine to me!

Thanks for the additional info. I'll try to test the connector both with the engine off and on when I get a chance.

[Movin]

My engine control module holds code 15 and code 17, and code 25 after shutting off.
Is your KAPWR bad?

[XFSE71]

My engine control module holds code 15 and code 17, and code 25 after shutting off.
Is your KAPWR bad?

A quick look at my new 1993 Festiva EVTM that came with the new Shop Manual shows keep alive is fed by the room fuse along with the radio, dome/cargo lights and shift interlock on ATX.
I did find the 10A Room fuse blown because the dome light switch had disintegrated from the heat shorting the power terminal to ground. I just put a new micro switch up there. There was no radio in the car, and it appears the shift interlock has been disabled. So YES, I stand corrected, KAPWR has to be hot at all times to store codes. Mine was not right. good catch Movin.