I have a 1994 7.3 idi and the overdrive light is flashing upon starting the truck. Is there a way I can pull the code and how? Thanks!

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Bought a code reader and got a code for throttle position sensor and transmission temperature.

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Is there anyway a throttle position sensor can make a truck lack power pulling hills?

 

yep, on driverside of injedtion pump. it needs to be set to get trans to shift correctly.
dont ask me how though, i tear out the autos and put manuals in.

 

The code for throttle position sensor won't. In a diesel truck the sensor is monitoring the injection pump lever posistion. Once any transmission code is set, you are in limp mode. Your transmission will shift very firmly in limp and continue to operate at max pressure until you shut your truck off. Limp mode was designed to allow you to get off of the road when the od light flashes without needing a tow. In your owners book it will tell you to only drive a short distance if the od light flashes and go have the truck checked out or repaired ASAP. The throttle position sensor code is an easy problem to fix.

The transmission temperature code is a much larger concern.

The temperature code means your transmission overheated. Overheat will make a truck lack pulling power whether the engine, transmission or axle overheats. Overheat will quickly ruin anything. The od light flashes when transmission fluid temperature rises above 280 degrees to signal the driver there is a problem that needs immediate attention.

Hopefully no damage was done. Contact us if we can help.

 

The transmission seems fine other than the firm shifting and I was less than 5 miles from home the transmission I wouldn't think had time to overheat but I will check the smell and color of the fluid.

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I would love to put a manual transmission in the truck but too much money to get that done yet...

 

what did you get for a code reader ?

 

For my house just a cheap one from AutoZone but the one that is at work is a genesis system and i was told it will do a lot more but haunt tried it yet

 

Your truck has Ford's EEC-IV system. It's a system that had a very long service life, and uses a simple 2 digit system for service codes.

A code reader that can accurately display the actual code number is the best type.

If you have the actual code numbers and want to post them, I can double check them in our data base. I know some Autozone code readers don't work correctly on all vehicles. I haven't heard them advertise they will read your codes lately either....

Good luck

 

The codes I got were 26 and 23

 

Yes, that's what they mean. However, if you don't follow the exact procedures for the specific vehicle when reading codes, you will actually get both false code 26 and 23 results on your code reader.
Auto Zone may have found this out the hard way...

The exact procedures for all On Board Diagnostics is beyond what I can post. They are covered in a diagnostics book with 5000 or so pages and updated with service bulletins as needed.

What I can do is tell you 2 things to avoid getting false 26 and 23 codes when running a key on engine off test with your code reader. On a 94 diesel, the throttle has to be held wide open until codes begin to output, then released. The truck must be at normal operating temperature before reading codes in key on engine off mode to get accurate results. If your truck wasn't warmed up first and the throttle signal wasn't triggered as above to your truck's PCM (computer) than re-run your self test.

Not sure what Auto Zone's diagnostic stuff is capable of on vehicles it can read codes on. In a nutshell when you read codes, you are prompting your PCM to go into self test mode. There are 2 modes with different types of code outputs. There are key on engine off with hard fault code output and codes stored in memory output mode on your truck. Also engine running self test modes with code output. Both modes require you to perform the specific prompts for the vehicle to run self tests and get accurate results.


As popular as advocating a swap to a manual transmission is, there are downsides to doing it. They just have different problems. One is they are prone to cracked cases. Cracked manual transmission cases were outlined in a Ford TSB covering 89 and up trucks with 7.3 engines. Dual mass flywheel, clutch and syncro failures, slave cylinder and linkage problems were others. Eventually Ford or the aftermarket provided a fix for most problems whether you prefer a stick or automatic transmission. Cases are one exception, new oem or a used replacement is the only option.

Again, If your truck wasn't warmed up first and the throttle signal wasn't triggered as above to your truck's PCM (computer) than re-run your self test. Good luck.

 

i am having the same problem with mine only i already replaced the throttle possition sensor and some others but am have the same problem i would really like to get it fixed although it is like it has become an everyday normal thing. im just afraid of breaking something in the tranny.