I have a early 99 that melted the wiring harness around the ipr and fuel heater driver wires and it damages about half the wires in the harness. I cut the bad out soldered new wire in and now I got some issues. The truck runs but the icp ebp map reading aren't right and move around to much. I've checked rechecked and ohm readings on the harness and it's good. When I ohm from the 5v reference to battery ground I get around 350 ohms it's suppose to be 1000 or more. I also can unhook them and it will ohm out to like 9.2k ohms. I can hook them all back up besides the map sensor and be over 1000 ohm but if I plug in the map reading stays at 350 ohms even after I unhook it. To get it to get a high reading you gotta unhook the harness at pcm or 42 pin. The pcm is a awa3 I also have a s0d4 that I plugged in and it held a 1.5k ohm reading so I think it's shorting out in the pcm. Can the s0d4 work with the early 99?

 

I am running a different alpha coded PCM (tuning strategy) from what I was running originally. It runs fine. The most important number on the two PCMs is the "DPC" number up on the plug. They should match. That code denotes your hardware setup on your chip/card inside (as I understand it). The alpha code is the software version/tuning strategy (as I understand it).

I grew up near Perryville. Not far from you.

 

I have (had) the AWA3 for my e99 f250 manual. Swapped it out with a CLB5 (99 manual 450/550/650) so that I could keep the A3 as a spare. Runs great but am sorting out a Wait to Start light constantly on issue (have another post on this in process).


The SOD4 sounds like it is a PCM from a much later year. On this site, there are a few posts that have a list of all the PCM tags, which includes year and some details about what they applied to. When I checked the CLB5 on the list, it seemed it was near the end of those that went with the 99 MY.


As noted above the "DPC" is most important to match. The AWA3 is DPC 401 (odd numbers for manual trans), so at a minimum that needs to align. DPC 421 may also be a fit, but that will have to be confirmed. When I was ordering another PCM so that I could keep the AWA3 as a spare, I learned from the vendor that there are all sorts of things to consider for replacement. So heads up.

 

The SOD4 is from a 94.5-95 manual. There are a lot of differences between the two PCMs in question. At a minimum, repinning the PCM connector and installing the correct Manifold Absolute Pressure sensor are in your future. Also, the stock calibration on the older PCM will not run the split-shot injectors correctly. It's possible to do, but you'd be better off with the correct PCM or one from a 1995-2001.

 

Thanks for the info. I knew it was from a obs truck and wouldn't run splits but didn't know pin out was different. Is there a way to test the pcm 5volt reference cuircuit for shorting to ground? If the pcm got 12 volts send to it threw the 5volt reference pin 21 on the 42 pin connector could it cause the issue of having a off and on 350 ohm reading to ground on that circuit when the map sensor is plugged in and stays at 350 ohms with all sensors unhooked including the map sensor

 

You can test the 5V reference for short to ground easily. Put the black lead on the negative battery terminal, and touch the red lead to the pin on the plug for the 5V reference. It should be open. Use the 20 Ohm setting and make sure there is no key in the ignition (no power to circuit).

 

Nicmike. I have done that on all the sensors where the pin 21 goes on my truck it's a brown wire with white stripe. On my map sensor when I plug it in and check the icp or ebp sensors pin 21 brown with white strip wire my ohm readings go below 1000 ohms they stay around 350-500. If I unplug the map sensor the readings don't go back up. If I unhook the icp ebp tps baro and cam sensors it still won't go above 1000. If I unhook the pcm or 42 pin it clears out and goes back up over 1000. The truck does run but not good. And also does odd things like if you unplug the ebp sensor and start it. It romps like the icp sensor is bad. When it's idling the icp is around 2000. If you hit the throttle it drops to 500ish and goes crazy.

 

I revisited the list earlier today and realized that ascending tag names do not correlate to increasing model years.


A question about strategies - how does one review the written code associated with them? Is the code published somewhere?