nikitis
1994 International 3800 - Thomas, T444E 165HP
I'm making this thread as an authoritative thread on what to do if you own a 1994-1997 International Harvester Bus or Tractor with a 3 Box internal computer and there are issues or if you want to know how to get them fixed in 2024 and beyond. At least what we know.
History:
The 3 Box is one of the first computers put into a Tractor Trailer / Bus. Prior to 1994 most IH machines were all mechanical. The 3 Box was the first attempt as computerizing the T444E and DT466 Engines.
What is a 3 Box?
Today most ECU's have all 3 of the functionality into 1 box, but originally these functionalities of the Injector Driver (IDM), Vehicle Personality Module (VPM), and Main Central computer (ECM) which links them all together where separate and on separate boxes. This later proved to be a larger headache for the dealerships and manufacturers, so now today all of these functions and more are built into one ECU. VPM contains vehicle personality settings like how hard to run the engine, speed control, etc. The VPM tells the ECM basically how hard should I run this engine? and the ECM runs the engine, and the IDM runs the injector controls based on what the ECM tells it.
How do we interface with these computers?
All of these that I'm aware of use J1708 Interface ports. This is an industry standard that predates an OBD2 port and uses 6 pins, is round, and gray in color. There was J1708 which were the first ports, then later around 1997 (on some rare machines) but mostly after the year 2000 came the J1939 port which is a 9 pin interface, round, same circumference as the J1708 but is green in color to help differentiate between the J1708 and J1939. OBD2 was around in 1997, but not on Tractors/Buses. Toyota was putting OBD2 in their cars in 1997, but not in larger trucks.
I have a 3 Box Bus/Tractor, and I have a permanent Warning Light on, what do I do?
First see if you can extract the codes. This can be done in one of 2 ways on a 3 Box. You can interface to the J1708 using a Nexiq 2 USB devices and a Windows 7 32-bit laptop, and possibly later. or a Bluefire, or any device reader designed to read from J1708, and pull the codes this way.
Or
If you don't have an expensive reader, there is a flash push button under the dash sometimes located next to the J1708 or in the center of the dash, if you insert the key, to the ACC position, and push and hold the button it will start a flashing code system on the gauge cluster. The Warning light will flash consecutively a certain amount of times at a certain quick speed, you must count how many times it flashes. This is the first number of the first code. Then it will pause briefly, then flash another set of times, that will be the second number, then a 3rd time, which is the 3rd number in the code. You will write these down on paper as they happen because they happen quickly. Then a pause and a flash of the Parking break light on the gauge cluster signifying a new code. Rinse and repeat to get the second code. This will continue until you see the parking break light flash 2 times, then you will get the inactive codes flashed at you or long term storage codes. Then after those are presented the parking break will flash 3 times telling you it's over.
Once I have the codes what do I do?
Look them up using the T444E diagnostics PDF which is floating around. Ask on here and you shall receive. Look up the term "Flash Code 223" as an example in the PDF to find out what the code means to give you a clue as to what is wrong with your Bus. From there ask around on how to fix and find out if it's something you can fix on your own or if you need assistance from a dealership.
I'm not getting codes from a Nexiq USB reader or Bluefire or any other devices, what's up?
This can mean one of two things on a 3 Box. Your ECM is dead or your VPM is dead or not powered or data lines are bad. Let's go over the scenarios for understanding purposes and diagnosis purposes.
Scenario 1: ECM is working VPM is not:
Your ECM could still be working even though you cannot read the codes. This is because the wiring in simple terms goes from ECM => VPM => J1708 Port. If the VPM is dead, the ECM won't be able to relay the codes through the port as the VPM is the front line interface for the J1708 port. But you can still get codes using the flash code push button method described above. This is evidence your ECM is in good shape because it's still able to deliver you the codes. This is the evidence you need to know the ECM is good, and that there is a problem with either 1.) The data lines from ECM to VPM are bad, or VPM to J1708 port are bad, or 2.) The VPM in the middle is dead, or not properly grounded and not getting power.
Scenario 2: ECM is broken, VPM is or is not:
If you cannot get data from the J1708 port, And you cannot get flash codes to work via the push button method your VPM is likely fine, but the ECM is dead or not powered. Flash code button method is in place to bypass the VPM if it's an issue to tell you the VPM is dead. If this does not work, then the ECM is shot, or the lines are bad to the ECM in two places which is unlikely so it's likely the ECM is shot.
Scenario 3: ECM is working, VPM is working, but no data.
If you get nothing from the J1708 port and it's not your reader device, and the VPM is working, but ECM is not working, it could be an aged or corroded line. Twisted pair is used between VPM and J1708 and also ECM to VPM. They require 2.0 ohms and can go up to 2.9 ohms in testing on a multimeter, much over 2.9 ohms and you will have data communications issues. 2.9 is still bad and could still have issues, you want to be under 2.0 ohms of resistance, so if you are over 2.0 you may want to replace the lines. Make them as short as possible to reduce resistance. Test ohms resistance again after replacement. You can test by unplugging the VPM which is extremely difficult to reach. They did not want people accessing the VPM. The ECM is a little easier but still difficult to pull out. Rarely the VPM is the issue electronically but was in my case. Usually the ECM is more likely the culprit. Assuming Lines are replaced from ECM -> VPM, and VPM -> J1708 and under 2.0 ohms of resistance and both devices are working you should now be able to communicate over the J1708 port. If you still cannot, verify ground and power pins on the J1708 port. You can google search for the pinout for which pins those are.
Scenario 4: Both VPM and ECM tested good, lines are tested good.
Verify power to the relays. Most buses and Tractors have 3x 5-port relays mounted to the IDM box on buses, and some tractors may be located elsewhere but should be 3 of them. A main ignition and power line goes to these relays and they can go bad. Replace all 3 relays to rule them out. We can go further into relay testing but that's not the focus of this article. Relays are cheap enough, just replace them so it doesn't strand you down the road costing you an expensive tow. Replacing relays is a good start, and if there is still an issue, check the fuses next. There are two fuses usually at the battery box itself on the positive line. Find the fuses and ensure they are good, replace if bad and test. Next check the fuses in your main fuse box panel which is inside in the middle of the dash on Buses. Ensure all fuses there are good. If everything is in order after replacing dead fuses all should work.
Scenario 5: The IDM is broken, but ECM and VPM is good.
In this case you will be able to get codes from a J1708 reader and from push button flash code method. But your engine will not start. ECM should tell you easily via codes that the IDM is bad and may need to be replaced. If the IDM is bad in the 3 Box system, the engine will not fire the injectors properly and the engine will not start. This will have to be sent back to be remanufactured in 2024 and later years because there are no new IDMs.
There may be another scenario I have failed to mention, but these are the ones I'm aware of and cover pretty much the whole 3 box wiring and encounters one will encounter.
I have determined I have a bad ECM/VPM/IDM, what do I do?
This is a good question, and one that in 2024 is a pickle, but not completely out of options. There many many buses made out there, and the 1994-97 buses are international trucks really, so all of the trucks with the same model number as your bus, i.e. 3800, 4800, etc, should share the same 3 box system, but with different firmware. Replacement parts exist in hardware and is the same, but will require to be flashed by Navistar/International dealerships so they can talk to each other and to have your VIN parameters put into them.
There are NO NEW PARTS! Zilch, nada. There are ebay replacements. Some will work some will not, even with a matching part number. This is because some devices get flashed with newer firmware. When a device is made it's released with a firmware version, and a part number is tied to that firmware version, but if during it's lifetime it was firmware updated, the part number will only reflect the old firmware so by buying on ebay a part such as a VPM, it may come with an updated firmware and still require flashing the ECM/IDM to match. A program is likely going to be required to get a 3box up and running again and that has to be done using NavKal by a dealership which pulls the firmware "calibrations" together on all 3 boxes as the same time. So you are taking a risk if you buy on ebay. Ebay is still good to get the hardware, but expect that you may have to haul it to a dealership to get it programmed to make it work with your other 2 boxes.
Navistar Hardware Replacement Program:
Navistar/International does have a program in place still for us 3 Box users, even past their 15 year part guarantee. There's too much demand still for users needing these fixed/repaired and still in use so as of 2024 this program is still in play, however there is something you NEED to know about this program.
1.) The way this program works is, you have a Warning Light, you determine from flash codes you have a bad ECM/IDM/VPM or one of the 3 box items. You call a local dealership, you give them your VIN, they look up your 3 Box Bus / Tractor, and find every part is in RED on their screens. This means no parts available. Some dealers will stop there. Interrupt them, and tell them to check the foot note on the ECM/VPM/IDM parts, it will tell them about a program that exist to service these items, the dealership guy on the phone will go "Huh, interesting, that's unusual", the program details will have the correct address to send the items to, to be remanufactured" which is a place called "Flight Systems", and it will tell them that they will program it. This is NOT TRUE. Flight systems is the company that made the 3 Box systems hardware, and that division has split off into many divisions, and a division called "Dorman" now remanufactures them, if you called Dorman and reach that remanufacturer division on the phone they'll still call themselves "Flight Systems".
2.) Dorman (Flight Systems) ONLY DOES HARDWARE!!! Remember, YOU are educating the parts dealer as these are 27-30 year old parts, they have NO IDEA what needs to be done. YOU MUST EDUCATE THEM on this process!
Dorman will receive the broken parts sent to them by the Dealership. YOU cannot send it to Dorman for repair, their replacement program does not cover the costs if YOU send it to them, it must be from a Dealership. And Dorman will fix the units like brand new, and ship them back to the Dealership BLANK!
3.) If you do not educate the foreman on your issue about this process properly what will happen next is they will get the VPM/ECM or ICM back, Blank and state "What am I supposed to do with a blank module?" And refund your money and you are left with a broken Bus/Tractor in an unrepaired state.
4.) Once the dealership gets the blank unit back. All 3 box computers are required to be plugged in for programming, and firmware needs to be updated on ALL 3 boxes so they can communicate. Dealerships are to use NavKal software to do this. Tell them they need to use NavKal. THEY DON'T KNOW HOW TO DO THIS!
You can provide the Dealership foreman/mechanic the Navistar Internal Knowledge base article IK2600143. Tell them to look that article number up and it will explain how to program them. Once their mechanic looks it over he'll understand what he needs to do and will have learned something new, and you'll have a working 3 Box Bus/Tractor again in the year 2024 and beyond!
I hope this was informative and will assist anyone else with an International Harvester Bus/Tractor from the years 1994-1997 and a 3 Box system up and running again.
History:
The 3 Box is one of the first computers put into a Tractor Trailer / Bus. Prior to 1994 most IH machines were all mechanical. The 3 Box was the first attempt as computerizing the T444E and DT466 Engines.
What is a 3 Box?
Today most ECU's have all 3 of the functionality into 1 box, but originally these functionalities of the Injector Driver (IDM), Vehicle Personality Module (VPM), and Main Central computer (ECM) which links them all together where separate and on separate boxes. This later proved to be a larger headache for the dealerships and manufacturers, so now today all of these functions and more are built into one ECU. VPM contains vehicle personality settings like how hard to run the engine, speed control, etc. The VPM tells the ECM basically how hard should I run this engine? and the ECM runs the engine, and the IDM runs the injector controls based on what the ECM tells it.
How do we interface with these computers?
All of these that I'm aware of use J1708 Interface ports. This is an industry standard that predates an OBD2 port and uses 6 pins, is round, and gray in color. There was J1708 which were the first ports, then later around 1997 (on some rare machines) but mostly after the year 2000 came the J1939 port which is a 9 pin interface, round, same circumference as the J1708 but is green in color to help differentiate between the J1708 and J1939. OBD2 was around in 1997, but not on Tractors/Buses. Toyota was putting OBD2 in their cars in 1997, but not in larger trucks.
I have a 3 Box Bus/Tractor, and I have a permanent Warning Light on, what do I do?
First see if you can extract the codes. This can be done in one of 2 ways on a 3 Box. You can interface to the J1708 using a Nexiq 2 USB devices and a Windows 7 32-bit laptop, and possibly later. or a Bluefire, or any device reader designed to read from J1708, and pull the codes this way.
Or
If you don't have an expensive reader, there is a flash push button under the dash sometimes located next to the J1708 or in the center of the dash, if you insert the key, to the ACC position, and push and hold the button it will start a flashing code system on the gauge cluster. The Warning light will flash consecutively a certain amount of times at a certain quick speed, you must count how many times it flashes. This is the first number of the first code. Then it will pause briefly, then flash another set of times, that will be the second number, then a 3rd time, which is the 3rd number in the code. You will write these down on paper as they happen because they happen quickly. Then a pause and a flash of the Parking break light on the gauge cluster signifying a new code. Rinse and repeat to get the second code. This will continue until you see the parking break light flash 2 times, then you will get the inactive codes flashed at you or long term storage codes. Then after those are presented the parking break will flash 3 times telling you it's over.
Once I have the codes what do I do?
Look them up using the T444E diagnostics PDF which is floating around. Ask on here and you shall receive. Look up the term "Flash Code 223" as an example in the PDF to find out what the code means to give you a clue as to what is wrong with your Bus. From there ask around on how to fix and find out if it's something you can fix on your own or if you need assistance from a dealership.
I'm not getting codes from a Nexiq USB reader or Bluefire or any other devices, what's up?
This can mean one of two things on a 3 Box. Your ECM is dead or your VPM is dead or not powered or data lines are bad. Let's go over the scenarios for understanding purposes and diagnosis purposes.
Scenario 1: ECM is working VPM is not:
Your ECM could still be working even though you cannot read the codes. This is because the wiring in simple terms goes from ECM => VPM => J1708 Port. If the VPM is dead, the ECM won't be able to relay the codes through the port as the VPM is the front line interface for the J1708 port. But you can still get codes using the flash code push button method described above. This is evidence your ECM is in good shape because it's still able to deliver you the codes. This is the evidence you need to know the ECM is good, and that there is a problem with either 1.) The data lines from ECM to VPM are bad, or VPM to J1708 port are bad, or 2.) The VPM in the middle is dead, or not properly grounded and not getting power.
Scenario 2: ECM is broken, VPM is or is not:
If you cannot get data from the J1708 port, And you cannot get flash codes to work via the push button method your VPM is likely fine, but the ECM is dead or not powered. Flash code button method is in place to bypass the VPM if it's an issue to tell you the VPM is dead. If this does not work, then the ECM is shot, or the lines are bad to the ECM in two places which is unlikely so it's likely the ECM is shot.
Scenario 3: ECM is working, VPM is working, but no data.
If you get nothing from the J1708 port and it's not your reader device, and the VPM is working, but ECM is not working, it could be an aged or corroded line. Twisted pair is used between VPM and J1708 and also ECM to VPM. They require 2.0 ohms and can go up to 2.9 ohms in testing on a multimeter, much over 2.9 ohms and you will have data communications issues. 2.9 is still bad and could still have issues, you want to be under 2.0 ohms of resistance, so if you are over 2.0 you may want to replace the lines. Make them as short as possible to reduce resistance. Test ohms resistance again after replacement. You can test by unplugging the VPM which is extremely difficult to reach. They did not want people accessing the VPM. The ECM is a little easier but still difficult to pull out. Rarely the VPM is the issue electronically but was in my case. Usually the ECM is more likely the culprit. Assuming Lines are replaced from ECM -> VPM, and VPM -> J1708 and under 2.0 ohms of resistance and both devices are working you should now be able to communicate over the J1708 port. If you still cannot, verify ground and power pins on the J1708 port. You can google search for the pinout for which pins those are.
Scenario 4: Both VPM and ECM tested good, lines are tested good.
Verify power to the relays. Most buses and Tractors have 3x 5-port relays mounted to the IDM box on buses, and some tractors may be located elsewhere but should be 3 of them. A main ignition and power line goes to these relays and they can go bad. Replace all 3 relays to rule them out. We can go further into relay testing but that's not the focus of this article. Relays are cheap enough, just replace them so it doesn't strand you down the road costing you an expensive tow. Replacing relays is a good start, and if there is still an issue, check the fuses next. There are two fuses usually at the battery box itself on the positive line. Find the fuses and ensure they are good, replace if bad and test. Next check the fuses in your main fuse box panel which is inside in the middle of the dash on Buses. Ensure all fuses there are good. If everything is in order after replacing dead fuses all should work.
Scenario 5: The IDM is broken, but ECM and VPM is good.
In this case you will be able to get codes from a J1708 reader and from push button flash code method. But your engine will not start. ECM should tell you easily via codes that the IDM is bad and may need to be replaced. If the IDM is bad in the 3 Box system, the engine will not fire the injectors properly and the engine will not start. This will have to be sent back to be remanufactured in 2024 and later years because there are no new IDMs.
There may be another scenario I have failed to mention, but these are the ones I'm aware of and cover pretty much the whole 3 box wiring and encounters one will encounter.
I have determined I have a bad ECM/VPM/IDM, what do I do?
This is a good question, and one that in 2024 is a pickle, but not completely out of options. There many many buses made out there, and the 1994-97 buses are international trucks really, so all of the trucks with the same model number as your bus, i.e. 3800, 4800, etc, should share the same 3 box system, but with different firmware. Replacement parts exist in hardware and is the same, but will require to be flashed by Navistar/International dealerships so they can talk to each other and to have your VIN parameters put into them.
There are NO NEW PARTS! Zilch, nada. There are ebay replacements. Some will work some will not, even with a matching part number. This is because some devices get flashed with newer firmware. When a device is made it's released with a firmware version, and a part number is tied to that firmware version, but if during it's lifetime it was firmware updated, the part number will only reflect the old firmware so by buying on ebay a part such as a VPM, it may come with an updated firmware and still require flashing the ECM/IDM to match. A program is likely going to be required to get a 3box up and running again and that has to be done using NavKal by a dealership which pulls the firmware "calibrations" together on all 3 boxes as the same time. So you are taking a risk if you buy on ebay. Ebay is still good to get the hardware, but expect that you may have to haul it to a dealership to get it programmed to make it work with your other 2 boxes.
Navistar Hardware Replacement Program:
Navistar/International does have a program in place still for us 3 Box users, even past their 15 year part guarantee. There's too much demand still for users needing these fixed/repaired and still in use so as of 2024 this program is still in play, however there is something you NEED to know about this program.
1.) The way this program works is, you have a Warning Light, you determine from flash codes you have a bad ECM/IDM/VPM or one of the 3 box items. You call a local dealership, you give them your VIN, they look up your 3 Box Bus / Tractor, and find every part is in RED on their screens. This means no parts available. Some dealers will stop there. Interrupt them, and tell them to check the foot note on the ECM/VPM/IDM parts, it will tell them about a program that exist to service these items, the dealership guy on the phone will go "Huh, interesting, that's unusual", the program details will have the correct address to send the items to, to be remanufactured" which is a place called "Flight Systems", and it will tell them that they will program it. This is NOT TRUE. Flight systems is the company that made the 3 Box systems hardware, and that division has split off into many divisions, and a division called "Dorman" now remanufactures them, if you called Dorman and reach that remanufacturer division on the phone they'll still call themselves "Flight Systems".
2.) Dorman (Flight Systems) ONLY DOES HARDWARE!!! Remember, YOU are educating the parts dealer as these are 27-30 year old parts, they have NO IDEA what needs to be done. YOU MUST EDUCATE THEM on this process!
Dorman will receive the broken parts sent to them by the Dealership. YOU cannot send it to Dorman for repair, their replacement program does not cover the costs if YOU send it to them, it must be from a Dealership. And Dorman will fix the units like brand new, and ship them back to the Dealership BLANK!
3.) If you do not educate the foreman on your issue about this process properly what will happen next is they will get the VPM/ECM or ICM back, Blank and state "What am I supposed to do with a blank module?" And refund your money and you are left with a broken Bus/Tractor in an unrepaired state.
4.) Once the dealership gets the blank unit back. All 3 box computers are required to be plugged in for programming, and firmware needs to be updated on ALL 3 boxes so they can communicate. Dealerships are to use NavKal software to do this. Tell them they need to use NavKal. THEY DON'T KNOW HOW TO DO THIS!
You can provide the Dealership foreman/mechanic the Navistar Internal Knowledge base article IK2600143. Tell them to look that article number up and it will explain how to program them. Once their mechanic looks it over he'll understand what he needs to do and will have learned something new, and you'll have a working 3 Box Bus/Tractor again in the year 2024 and beyond!
I hope this was informative and will assist anyone else with an International Harvester Bus/Tractor from the years 1994-1997 and a 3 Box system up and running again.
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