E4OD Issue - O/D Light flashing

Discussion in '6.9L IH & 7.3L IDI Diesels' started by peacetank, Jan 5, 2009.

  1. peacetank

    peacetank Registered User

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    Here is a brief description of my most recent ambulance purchases:
    I have a 1994 E-350 ambulance w/7.3 IDI (along with the others). I bought it, the '92 ambulance, and a suposidly good spare engine and E4OD tranny for $850 in 2007. The ambulances, wich both run, have sat at the ambulace company since 2004. The '94 has only 30k on the rebuilt engine and tranny, while the '92 has 162k on the origional engine.

    I have finnaly been able to get the '94 ready to temporarily replace my ailing truck. I have changed all of the fluids, including the transmission fluid and filter. I drove the '94 on the highway for the first time the other day. (Keep in mind it has only been on the road for about a week since '04.) Everything was fine when I parked it, but when I started it back up again the O/D light was flashing steadily and the shifting was harsher than normal (indicating the tranny has increased presure). I do not know if this has anything to do with my problem, but my speedometer has always bounced all over the place. In an effort to fix that problem, I replaced the speed sensor in the rear end. It seemed to help the problem but not fix it (it now starts bouncing at 40 mph instead of 15). I have also replaced the TPS in an effort to fix my tranny problem with no results. Where do I go from here? Does the bouncing speedometer have something to do with my problem?

    Although not really related to my problem, I also replaced the stock tranny cooler and upgraded to 5/16" lines.
     
  2. discbrks

    discbrks Registered User

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    Does the odometer work? I might be completely wrong here - but I'll say this. I had a loose connection on my odometer, which also works the speedometer. The harness came loose, causing the speedometer & odometer to quit... and so the trans. started shifting hard. Maybe the speedometer is the cause?
     
  3. peacetank

    peacetank Registered User

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    The odometer does work - I don't know how accurate it it, but I can't help but think the speedometer might have some connection with the tranny problem. As I mentioned, the problem didn't occur until I hit highway speeds then parked it.
     
  4. argve

    argve Resident Fruitcake Staff Member

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    is the tach working correctly?
     
  5. david85

    david85 Full Access Member

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    Does this year of van have a speedo cable? I know the F series changed over to pip signal for the speedometer in 1992, but not sure about the E series.

    I also second the question about the tach (if so equipped).
     
  6. peacetank

    peacetank Registered User

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    It has no tach - it's an econoline van. My latest idea is that there is a bad connection where the wiring harness plugs into the tranny. One of the terminals had a little corrosion, and the Ford book says that if one of the wires looses signal, it can result in the symptoms that it has. I'm going to look into that.

    It has no cable - like I said I replaced the sensor on the rear end.

    :smash: This is why automatic transmissions and electronics (even worse - the combination of both) are bad! :peelout
     
  7. david85

    david85 Full Access Member

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    Loose connections anywhere in the wiring will cause problems. But you are right about the connection on the side of the transmission (passenger side one that feeds the solenoid body). Its a very common problem.
     
  8. jdchristian3

    jdchristian3 Full Access Member

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    have it towed to a trans shop. DONT drive it. when the OD light flashes you have major issues. if driven, it could cause failure. it needs to be scanned and logged while driving, so all sensors are watched.
     
  9. peacetank

    peacetank Registered User

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    I have not driven it since, but my Ford service manual says that a flashing O/D light is caused due to the following "condition:"

    "Voltage through EPC circuit is checked and compared after a time delay. An error will be noted if tolerance is exceeded during KOEO and continuous Self-Test." --- It says this is caused by an "EPC circut failure or shorted output driver."

    This is the only thing in the book I could find out about a blinking O/D light. Do you know of the more serious conditions that would cause the light to blink?​
     
  10. GenLightening

    GenLightening Yeah, it's a CHEVY!

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    You need to pull the codes from the tranny. Also, even though you don't have a tach, you should still have the sensor for it, as the computer needs that signal to work. You might check the connector for it. It sits to the right of the oil fill tube, a large nut with 2 wires coming out of it. Also check the connections at the trans, both sides. If none of that works, you may need to open the rearend up to check the signal ring for the speedo.
     
  11. LCAM-01XA

    LCAM-01XA Full Access Member

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    Eh, it depends - flashing OD light means the PCM has entered limp mode, which usually means 2nd gear and full line pressure. If trans ain't slipping and fluid don't smell and/or look burned up chances are tis electrical issue, in which case the trans will not get damaged if driven. His wallet will definitely take a serious damage if he has the truck towed to a trans shop tho, it seems there are very few honest mechanics left out there so he'll likely get slapped with at least an hour's worth of work even if it takes them just 5 minutes to located a loose harness or plug and fix it. I'm a firm believer that shops are for people who don't have the equipment/tools for the job, don't know have the knowledge/skills to perform the job, or are just too darn lazy to even be bothered with diagnostics let alone performing any repair...
     
  12. peacetank

    peacetank Registered User

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    Don't worry - it won't be going to any tranny shop - besides, I have a spare tranny anyhow (I just hope its good and I hope I won't need it). I will try to have my dad pull the codes on Wed, which should get things narrowed down.

    I'm still not sure why the spedo isn't working properly after replacing the speed sensor - will check the signal ring.
     
  13. david85

    david85 Full Access Member

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    Also follow the wiring harness back from the VSS connector. Some have reported damaged wires that can cause problems like you are having.
     
  14. tuckerd1

    tuckerd1 WAR DAMN EAGLE!

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    Flashing OD light can mean several things. I'm no expert so I won't try to list them. But my 93 has had the flashing light many times since it was new. Every time but once it was a slipped Torq Conv code. Once it was for a TPS gone bad. I would usually disconnect the batteries and see if the bad code cleared. It did until I finally rebuilt it at 187,000 miles.

    If it shifts through all gears, even though hard, disconnect the batteries to clear the bad code and try it again. If flashing light comes back, get a code reader. You can get a code reader for ~$40.
     
  15. peacetank

    peacetank Registered User

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    So far - So good

    I disconected the batteries like you suggested, and so far... so good. I took it for a nice long test drive, and the light never came back on and shifting is back to normal, so I'm hoping that the TPS that I replaced was the problem. My speedo is still going crazy, however.
     

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