Can't find what this code means

[rcfast]

I'm getting code 999, I have checked about 30 times and its flashing code 999. Anyone have any idea what this means?

 

[ExplorerDMB]

there is no code 999 for OBDI

-Drew

 

[rcfast]

there is no code 999 for OBDI

-Drew

Ya... I know that, this is why i'm asking what it means.

 

[IAmTodd]

You sure you're not just miscounting them? Possibly multiple codes.

 

[MrShorty]

Two things that most closely resemble a KOER 999
1) KOER 998 - FMEM in effect. Normally one would expect to be seeing something other than a KOEO 111 with a KOER 998.
2) A 9 represents "pass" from the cylinder balance test. As it is possible to perform the cylinder balance test multiple times, I could see this as result of performing the cylinder balance test three times, getting a pass 9 code each time. However, with all that goes into entering and repeating the cylinder balance test, I would think it would be obvious if this is a possibility.

 

[rcfast]

Ya I have checked about 100 times. I will try and describe my problem a little more. If I do a KOEO I get codes 111 (pass) and then 157 (maf voltage high) for the CM. Then when I try to do the KOER right when I start the engine the light will kind of flicker like it does with the KOEO and then it will give a code just like with the KOEO and the code I get is 999, which it gives twice just like in the KOEO. After that it gives code 157 and then after it completes that it doesn't do anything. Just like in the KOEO. So i'm trying to figure out what is going on. I have checked the maf, maf wiring, TPS, IAC, ACT, ECT and they are all in range. I then checked all fuses, ecm relay, fuel pump relay and the two diodes, the I ran through this http://fordfuelinjection.com/index.php?p=44 and everything passed. So i'm pretty stumped to say the least, I'm thinking the PCM is toast but I will not be happy if I replace the PCM and the problem is still there. Maybe I will try and get a video of what is happening.

 

[rcfast]

I just decided to double check.. I'm getting code 998, not 999 I guess im retarded. So would 998 indicate a fried pcm?

 

[410Fortune]

wait wait wait if you get 111 that does not mean pass, because pass = no codes.
111 is likely the 3 flashes telling you its reading a v6 computer (2= 4cyl, 3= 6, 4=8)

157 sounds like you have a mas voltage issue, yet you say the MAS sensor itself is fine?
How do you know?

I am no expert, its been a long time since I did OBD-I tests with a CEL and jumper wire, but thats what I get from reading your posts.
I will leave the technical details to somebody who knows better like mrshorty here....

 

[rcfast]

wait wait wait if you get 111 that does not mean pass, because pass = no codes.
111 is likely the 3 flashes telling you its reading a v6 computer (2= 4cyl, 3= 6, 4=8)

157 sounds like you have a mas voltage issue, yet you say the MAS sensor itself is fine?
How do you know?

I am no expert, its been a long time since I did OBD-I tests with a CEL and jumper wire, but thats what I get from reading your posts.
I will leave the technical details to somebody who knows better like mrshorty here....

I get 111 with the KOEO and then get 157 for the CM. With the KOER I get 998 followed by 157, but never get 111 or 3 flashes for the KOER. The reason I say the MAF is fine is because it runs identical with the maf plugged in our unplugged, there is no difference in the way the engine runs either way. With it unplugged it should use a base fuel and timing table and it should run "decent".

 

[410Fortune]

hmmmmm I am not so sure about that my 93 ran like complete crap when the MAS was unplugged

what is 998 again?
let me go look it up.......

 

[rcfast]

hmmmmm I am not so sure about that my 93 ran like complete crap when the MAS was unplugged

what is 998 again?
let me go look it up.......

998, which is a hard fault and the computer is running in FMEM. Maf being unplugged or out of range will cause 998. I just really have this gut feeling it's the PCM and not the MAF though, But i'm not sure enough to go out and buy a new PCM. I know its either the MAF or PCM, I just need to decide which one it is.

 

[410Fortune]

998 doesnt mean much because remember you are supossed to cycle the brake switch and the steering wheel or something like that, if you dont then you wont pass?

I dunno

This page:
http://www.troublecodes.net/Ford/eec-iv.shtml

says 998 = hard fault present

 

[410Fortune]

I pray to god you have not skipped over cleaning the MAS and resetting the computer jsut because it runs the same when you unplug it???

 

[rcfast]

I pray to god you have not skipped over cleaning the MAS and resetting the computer jsut because it runs the same when you unplug it???

Ya that was one of the first things I did. I did some more thinking and a little more diagnosing and slightly leaned towards the MAF and decided to roll with that before I changed my mind. I found a MAF at a local parts store and purchased it.. I installed it and the problem is solved.. So as much as I hesitated and didn't think it was the MAF it was. I also ran a KOER after the new maf just to see and it ran the KOER fine and passed.

 

[410Fortune]

awesome! the code pointed to your issue....
I dont think unplugging the MAS and seeing how it runs will work on OBD-I trucks....if I unplugged it on my 93 engine it would barely idle...
maybe its an OBD-II thing?

Glad you got it fixed! Hope the new mas didnt cost $450..

 

[TheJMan]

awesome! the code pointed to your issue....
I dont think unplugging the MAS and seeing how it runs will work on OBD-I trucks....if I unplugged it on my 93 engine it would barely idle...
maybe its an OBD-II thing?

Glad you got it fixed! Hope the new mas didnt cost $450..

When I accidentally left the MAF unplugged on my 5.0, I didn't notice any issues at all, even when the CEL was on. Apparently, OBD-II vehicles have the capability to compensate for a sensor that has gone out of range by either inputting default values or drawing information from other sensors and using these calculated values. Amazing how smart vehicles are nowadays.

 

[410Fortune]

OBD-II compared to OBD-I is like sputnik vs space shuttle.

 

[ExplorerDMB]

OBD-II compared to OBD-I is like sputnik vs space shuttle.

haha can't agree more

 

[410Fortune]

seriously the way it was explained to me best is OBD-I or EEC-IV has 16 air/fuel ratio curves for the PCM to choose from, OBD-II or EEC-V has like 1600