CODE 21 & 24
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CODE 21 & 24
I get code 21 & 24 with new sensors plugged in. I get code 51 & 54 with new sensors unplugged. I got the same 21 & 24 codes before installing the new sensors. Any hints? The reader gives me an 11 which tells me the PCM is good. The PCM is brand new. Can the TFI module cause incorrect feedback to the PCM? Everything is new, except the TFI, and the truck cranks but will not start. I previously changed the coil and the truck started right up, ran for a day, and now will not start. It does try to start but won't quite catch. Timing is spot on.
Lead Driver
Joined: Aug 2006
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From: Sand Lake, MI
21 and 24 are showing because you can't and haven't run it up to full temp before running the self test.
You'll need to post your Model year/engine and include trans info to give people something to work with for your other questions. Not many differences across the models but there are a few that do make a difference as to info provided when troubleshooting.
Easiest way if only one truck can be creating a signature including that information, that way it is included in every post you make.
And while it is a good sign it is possible to get a "system pass" return from a computer that is suffering issues.
You'll need to post your Model year/engine and include trans info to give people something to work with for your other questions. Not many differences across the models but there are a few that do make a difference as to info provided when troubleshooting.
Easiest way if only one truck can be creating a signature including that information, that way it is included in every post you make.
And while it is a good sign it is possible to get a "system pass" return from a computer that is suffering issues.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
You should be getting three digit codes. Ford started to transition from two digit to three digit codes around 1991. A 1993 model year truck with a 5L engine and E4OD will most likely display three digit codes. It's not impossible to get two digit codes, just unlikely given the model year.
How did you pull the codes? with a reader or counting flashes.
How did you pull the codes? with a reader or counting flashes.
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Not true. From 1985-1995 the code can be both 2 and 3 digit. OBDI is a non-standard system and varies from manufacturer to manufacturer. Basically, each manufacturer did what they wanted during this infancy of electronic control. In 1996 they finally all agreed to a basic standard, sort of.
Fleet Owner
Joined: Oct 2005
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From: Kentucky
Not true. From 1985-1995 the code can be both 2 and 3 digit. OBDI is a non-standard system and varies from manufacturer to manufacturer. Basically, each manufacturer did what they wanted during this infancy of electronic control. In 1996 they finally all agreed to a basic standard, sort of.
Read the threads on this forum closely, this is a VERY common mistake people make on this vintage truck. That's why I point out the transition date and reasoning why the codes may be interpreted wrong.
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That's my point exactly. It's a Ford, so there are always exceptions. When they run out of parts on the assembly line, they grab the next best thing. It could be from a Pinto. If you don't bring the VIN#, assembly date, and the part with you to the parts store, you are a fool.
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Fleet Owner
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From: Kentucky
There are always exceptions and who is to say the original computer is in the truck? I'll stick by my statement and again question how you retrieved the codes?
It's not the first time someone was hell bent on retrieving two digit codes when the truck was displaying three digit. It's a VERY common mistake. It's a moot point if a code reader was used and it would prove you have an exception to the loose rules.
All of us would be happy to help you, but we need to know some more details.
It's not the first time someone was hell bent on retrieving two digit codes when the truck was displaying three digit. It's a VERY common mistake. It's a moot point if a code reader was used and it would prove you have an exception to the loose rules.
All of us would be happy to help you, but we need to know some more details.
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Fleet Owner
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From: Easton,Ks
Not true. From 1985-1995 the code can be both 2 and 3 digit. OBDI is a non-standard system and varies from manufacturer to manufacturer. Basically, each manufacturer did what they wanted during this infancy of electronic control. In 1996 they finally all agreed to a basic standard, sort of.
#1 No F-series truck had a 3 digit code before 1989 then only the F53 had the 3 digit code with the E4OD until 1991.
No Ford F-series truck had 2 digit code after 1994.
#2 OBD1 on Ford trucks was by only one manufacturer namely Ford.
OBD1 was on Ford trucks from 1985-1998.
So it was a very standard system on Ford F-series & E-series trucks.
So your information source is totally wrong.
I also have a 1993 F-series truck with an E4OD and it has 3-digit codes.
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You're basically proving my point about the standard as there is none or there would be one set of codes for all transmissions, etc. There are so many conditions and exceptions it makes ones head spin. And GM has their OBD1 codes, Ford has theirs, etc. You can take a Ford OBD2 code and it is similar to most other manufacturers. And I did make a mistake on the trans. I looked up the model # of my PCM and the trans is an AOD. After whispering this error to the truck, it still wouldn't start... I had a 1985 Ford Ranger V6 4x4 long bed and that vehicle had 8 different possible universal joints. If that's what you call sane engineering, you can have it. I've always maintained that Ford makes the strongest truck available, but God help you if it breaks down.
4wd Low
Joined: Jan 2021
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You should be getting three digit codes. Ford started to transition from two digit to three digit codes around 1991. A 1993 model year truck with a 5L engine and E4OD will most likely display three digit codes. It's not impossible to get two digit codes, just unlikely given the model year.
How did you pull the codes? with a reader or counting flashes.
How did you pull the codes? with a reader or counting flashes.
Lead Driver
Joined: Oct 2016
Posts: 6,185
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From: Houston/Sugar Land
Hey Chris this thread is at least 6 years old but to clear it up for you, counting flashes is still two or three digit codes (never both) depending on year. We all have replied to old threads BTW
4wd Low
Joined: Jan 2021
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I am just working on my truck as we speak and I was referencing the forum to try and figure out what some of these codes meant in my vehicle and when I read that I knew that to be wrong at least from everything I had learned so far on my own so I wanted to comment on it for future people such as myself looking back at these old posts old threads and see if I could possibly save somebody a little bit of time and hardship I do have a question for you I was driving to work one day and my truck was in here I went around a corner I went to accelerate out and my truck still showed being in gear but it was not catching I guess is the word is this what is commonly known as gear slippage if so what is the best way to test and/or diagnose this I had recently done the rear differential fluid but other than that no work has been done to transmission since I've owned it this truck only has a hundred and fifty five thousand on it and it is a 93 Ford F150 5.0 rear wheel drive any help is much appreciated