Check Engine Light Help

Discussion in 'Fox 5.0 Mustang Tech' started by SFC_R0CK, Oct 31, 2008.

  1. jrichker, Thanks for the Ford factory wiring diagram manual. I have been looking it over and so far found that there is no difference between a manual and auto EEC
    harness, nor is there a difference between a manual and auto O2 harness. Lots of great information. I will update on what I find next.

    I replaced the EGR valve (known to be good) and still got a CM code 33 so I think I have something wrong with the vaccum.

    Does anyone have a in detail diagram of the vaccum lines for the tab, tad thermactor, egr lines so I can make sure they are correct.

    Thanks again guys for all the great information and help.
  2. PIN #30

    OK here is what i got,,,,,ford shows 2 harnesses 1 for auto 1 for 30 is what i can see from a book... pin 30 for auto is circuit 33 and is W/PK ,is for neutral drive switch/A/C Input circuit.,,,,,,,,,,pin 30 for manual is circuit 199 LB/Y and is for neutral gear switch and clutch switch that is a neutral drive circuit ,,,fun to learn .........your circuit for code 67 is this ,,,,clutch switch here is missing,,,,,,,,cause you had a auto,,and still have auto,,but harness you have is for manual,,,,,,,maybe a switch used at clutch pedal jumper is needed or modified,which also conrols your cruise control which doesnt work,,,,,hint in ford book other that pin 30 was in fa-5 check clutch pedal switch,,,,NOTE THE CLUTCH PEDAL MUST BE DOWN DURING KOEO TEST IF NOT A CODE 67 WILL switch ,also switch shuts off cruise ?
  3. need more info?

    my book is just wires with numbers..main harness has others inside..harness 14401 goes everywhere and i think its part of main harness but im in a book cant see .... my book shows pics of harness locations on 2.3,3.8,and 5.0 mustang,thats where i found harness change ,and most jumpers in the fine print.. can you describe in some detail or pic of complete harness?and any numbers from harness tags on this one and the old one
  4. circuit 199

    while im waiting for jr and your new info look at this pic from my 03 man,,,,,,,,,
  5. Ok guys here is the deal so it turns out there is a difference between a manual and auto O2 sensor harness. I took the O2 harness of my 89 vert AOD, and installed it and no more code 67. I guess that also means anyone that does an AOD to manual swap needs to switch out their O2 harness to get rid of their code 67 problem also the correct way.

    I want to thank hotcobra03, jrichker, HISSIN50 for all the help and time and advice.

    According to the Ford Factory manual jrichker sent me is how I found the problem and pin 30 is actually purple/yellow and turns into circuit 771.

    When the O2 harness connects there is a loop of some sort for man trans in the harness that the auto harness does not have so that causes something to read diff and give code 67 in an auto trans when using the man O2 harness.

    I am going to try and remove the one pin tomorrow and see if it works. Will let you know.

    Attached Files:

  6. awsome

    hey im still waiting on diagram link,,but remember back some replys i did say code 85 leeds to fuel control and o2s????????/ but hey does cruise work?????//
  7. have not driven car again yet. I just got the other O2 harness hanging under the car and plugged in to test it out. Tomorrow I will remove that pin and then take it out for a drive and post results. Still have to check EGR vaccum lines also because something is not hooked up right with those. And yes you did mention the code 85 which is why I took the canp soleniod off my 89 vert to eliminate that code. And I took my EGR off my vert but still got the code 33 so I know its a vaccum issue and not a mechanical or electrical issue with the EGR.

    I will post all updates and fixes as I get to them. The O2 harness pic is back in my last post. I highlighted the suspected pin that I will remove to see if it will work.

    Thanks again guys.
  8. need more or the pic?

    look closer at the pic...26 and 771 jump inside or around plug and pin into 199 pin 30 ,,,,, o2s use 90/94/687....
  9. dirty connector?

    where does wires go to from plug .......
  10. Ok here is the deal on the wire/pin in the manual and auto O2 harness.

    circuit 771 is purple / yellow stripe and is looped from one pin to another.

    You have to move one end of the 771 circuit, circuit 199 is not used for an auto trans it is used for a manual and that is why you get the code 67 with an auto.

    My digital camera does not want to download the photos but I made another wire diagram to try and explain what I found between the 2 harnesses I have laying front of me and tried on the car.

    Attached Files:

  11. need more of circuits

    ok you took circuits 771 to 26 and now its 771 to 199 and circuit 26 is now open?your harness in pic is for a you have the one for auto circuit 33 is w/pk .. i need complete circuits ends that is 1 end and pcm is another ..with knowing where 33 runs than you can see if circuits need more .and what is 26?
  12. On the manual harness there are only 2 771 pins even though the diagram shows 3 pins. The one highlighted in red is where it goes in the plug for a manual trans and the one highlighted in blue is where it goes in the plug for an auto trans.

    a manual harness is 771 to 199, with 26 open.
    so for an auto harness I moved it to 771 to 26 and left 199 open and no more code 67.

    pm me your email and I will send you the wiring diagram jrichker sent me and I used to trace this down its to big to send on here.
  13. Ok now that the code 67 is fixed, I decided to try to hook the EGR back up. I have a

    CM code

    33 - EGR valve opening not detected.

    I tried a known good EGR valve from another car still get code, also the ports on the back of the heads are plugged, vaccum line is hooked up.

    Will this code hurt anything?

    This is the same code I got with one of those EGR "simulators", the ones that turn the cel off but does not trick the computer into thinking the EGR is working.
  14. Code 33 - Insufficient EGR flow detected.
    Look for vacuum leaks, cracked vacuum lines, failed EGR vacuum regulator. Check to see if you have 10” of vacuum at the EGR vacuum connection coming from the intake manifold. Look for electrical signal at the vacuum regulator solenoid valves located on the rear of the passenger side wheel well. Using a test light across the electrical connector, it should flicker as the electrical signal flickers. Remember that the computer does not source any power, but provides the ground necessary to complete the circuit. That means one side of the circuit will always be hot, and the other side will go to ground or below 1 volt as the computer switches on that circuit.
    Check for resistance between the brown/lt green wire on the EGR sensor and pin 27 on the computer: you should have less than 1.5 ohm.

    See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)


    EGR test procedure courtesy of cjones

    to check the EGR valve:
    bring the engine to normal temp.
    connect a vacuum pump to the EGR Valve
    apply 5in vacuum to the valve.
    if engine stumbled or died then EGR Valve and passage(there is a passageway through the heads and intake) are good.
    if engine did NOT stumble or die then either the EGR Valve is bad and/or the passage is blocked.
    if engine stumbled, connect vacuum gauge to the hose coming off of the EGR Valve
    snap throttle to 2500 RPM (remember snap the throttle don't hold it there).
    did the vacuum gauge show about 2-5 in vacuum?

    if not, check for manifold vacuum at the EGR vacuum valve.
    if you have manifold vacuum then connect vacuum gauge to the EGR valve side of the vacuum valve and snap throttle to 2500 RPM.
    should read about 2- 5 in vacuum

    The operation of the EGR vacuum regulator can be checked by using a test light applied across the wiring connector. Jumper the computer into self test mode and turn the key on but do not start the engine. You will hear all the actuators (including the EVR vacuum regulator) cycle. Watch for the light to flicker: that means the computer has signaled the EGR vacuum regulator successfully.
  15. Attached Files:

  16. According to Joel5.0, an EGR code disables the EGR system and tells the computer not to add additi0nal spark advance that a functioning EGR needs. Other than a reduction in fuel economy, that is supposed to be the only problem. Some guys have reported a slight ping at cruse, but that varies from car to car.
  17. So unless I change that spacer to one with a hole that matches up to the intake, I should not be to worried about the code 33?
  18. Ok so I pulled the upper intake and took the spacer out and got a new gasket and marked out the center hole from the gasket onto the spacer and took a 7/8 wood flat bit and drilled a hole in the spacer so it matched up to the gasket and put the intake back together and cleared the computer and ran it to operating temperature and checked the codes and got


    :hail2: and :cheers: to all of you guys that had input and patience to help figure all these issues out.

  19. Posted via Mobile Device thats so cool ! Saved money and learned. Stangnet rocks, i got awsome help here and im hooked.