EFIDynoTuning Forum

BOOSTEDEVERYTHING wrote: ↑2024 May 30, 14:10 And the J1850 PWM PCMs are programmable usually. There were just certain ranger PCMs that were not. You could find someone with a good cable and have them try to reflash the pcm. Or maybe the dealership. Like I said…you have to have the correct cable and software and attempt to program it, if it will not program then it will need to be replaced. The new one looks and operates the same, it is just programmable. It may have been as simple as a couple jumpers or resistors that were just not installed on the older PCMs to allow for tuning. Or it could have been the type of eprom used in the older PCMs.

If you personally know a source for a rebuilt piece that wouldn't be *locked* I'm all ears. The few rebuilder/dealers I've contacted all state that what I will supplied with will be programmed to my trucks VIN, the pcm will be identical to what I have & NOT programmable.

I can let you know right now that the catchcode is JTC1

This like being stuck between a rock & a hard place.....
One doesn't know if the pcm IS one of the untuneable items, to find out one has to test it, one needs to spend a considerable amount of dollars to get the needed pieces to test it. If it IS untuneable then it has to be replaced with a tuneable item.....yikes

Take this from another approach...can this *white elephant* be replaced with a later pcm from the same equipped truck that would be MS-CAN/HS-CAN protocol & transfer the 98 tune to the later pcm...(assuming pin locations are near identical)

The adapter cable that I DO have is the vgate vlinker/usb adapter. It IS j1850 pass-thru capable but Forscan (that I make use of for my 2018 vehicle) is not feps capable.

jsa wrote: ↑2024 May 30, 15:18 Indeed there are a few multibank pcm's that need solder jumpers to allow J3 tuning. Easy enough to do.

Normally a change from UVPROM or EPROM to EEPROM would have a new hardware code, likewise a change from jumperless to jumpered.

Ok, I can understand that...similar to me having to jumper my computer motherboard bios to flash the bios.

I'll have to remove the pcm from its pocket in the engine bay firewall, I take it that the J3 port is located on the back end of the pcm chassis.

BOOSTEDEVERYTHING wrote: ↑2024 May 30, 12:23 The pcm in some of the old rangers were not programmable in any way available to the public at all and required replacement. A normal mongoose able or similar would be able to program the pcm if it is a programmable pcm.

LOL...oh joy of joys

I did reach out to one rebuilder FS1 (Flagship 1), the rep there did tell me a replacement for my truck would include all or any updates that were mandated, but the pcm is not built on a newer user friendly protocol. It would still be J1850 pwm.

^ Ahhhh.....there we go, that's the boat I'm in, the trucks pcm is the original item. The newer replacements you handled were they J2534 or FTDI based?

Given the current pcm as it presents itself...can it be programmed if one makes use of a J1850 adapter to *engage* pin 13 to send the 18v to begin the reprogram process?
If one is capable of doing this function what laptop based tuning program is needed to perform this function?

Quarterhorse went defunct 2 years ago? any of the items for sale are ridiculously expensive & other software items are also needed to do the programming process?

This essentially is my truck & its pcm

the *FEPS* requires a signal on pin 13, the adapter has to be J1850, Forscan is 2534 capable but not J1850
as far as I can decipher pin 13 on my FTDI based adapter is dead

*The Old Days

Ford’s first original-equipment tool was the New Generation Star (NGS). This tool started as an OBD-I tool and advanced to OBD-II. The giant capital-T-shaped tool is unmistakable. It used the same PCMIA cards (software memory cards) as the Tech2. Many seasoned locksmiths got one of these, because it was the only machine for a long time to perform passive anti-theft systems (PATS) functions. It was slow and had a small screen.

The tool worked well on the Standard Corporate Protocol (SCP) network. This network is known as J1850PWM in the SAE world. SCP used pins 2 and 10. This network was well-designed and ahead of anything else at the time. It was a two-wire network that allowed serial communication to the modules. It worked a lot like CAN. If one leg of the network were broken, the network would continue to communicate. However, the data rate was just 41.6 kilobits per second (kbps). To put the system’s slowness in perspective, dial-up internet speed was 56 kbps.

Naturally, programming pre-CAN Ford keys or modules was hampered by computer and internet speed. Ford made the switch to CAN from 2003 to 2007. The reason so many newer programming tools struggle with this system is because they’re too fast for the Pre-CAN system to handle.

The only odd part about the SCP network setup is the Flash EEPROM Programming Signal (FEPS), which is pin 13 on the OBD-II port. It’s nothing more than an 18-volt signal to the powertrain control module (PCM) to allow the module to accept the new programming. The FEPS circuit continued to be the Ford PCM programming system for years after. Even as Ford advanced through various CAN styles, FEPS remained. So, if you get a FEPS error when trying to program a PCM, it often is an error between the J2534 tool on pin 13 and the PCM.

Starting in 1996, Ford tried to move from the NGS to the World Diagnostic Solution (WDS). This was a tablet-based tool running Windows. It was big and bulky and not well-received, so it was more or less shoved aside and the NGS retained. However, a problem arose in 2003 when CAN came around, because NGS never was able to handle CAN. To account for that, the Vehicle Communication Module tool (VCM I) was created with a cradle to help with CAN on the NGS.

Brings me back to my original question.....what do I need where tuning this pcm is concerned?

The Vgate is limited to FTDI, its drivers are all FTDI, it is J2534 pass-thru capable, but not J3 capable. where the *control/programming* side is concerned the pcm doesn't recognize any scanner program that is interfaced by an FTDI adapter. I CAN monitor but not program.

I take it that the OBDLINK EX is the hardwired version.

Hi there:

the catch code is JTC1

it is listed in this pic from coretuning.net

What makes them awkward to retune?...I'm assuming it's because Forscan altho it can communicate by a J2534 adapter cannot program to this pcm which is PWM/FEPS because a J3 cable is needed?. my Forscan program & the Vgate adapter are FTDI based. At every attempt to run a *service* there is an interruption in the process due to the inability of the of the Forscan program & the pcm to communicate.