I can't really understand the pinout change as a reason for stalled development. There are only 3 pins that are used for actual communication; RX,TX and GND. My best guess is that these 3 would be on the SCI Bus, as a way to communicate with the outside world, and the Pin 2 (PCI) bus would be for internal communications between the various servers (Brake controller, Dash, Radio, Speed control. etc.). This theory is up for revision; it is simply a guess at this time. I think the communications is referred to as J1850 Bus.
FWIW, here is a rundown from the Service Manual. I have the Diagnostic Manual set on the way, next week I may be able to make a better determination. I have some Max 232 Level translators and may go ahead an order the diagnostic connector shell and pins and try to make a bare-bones TTL to RS-232 cable and take a look.
Data Link Connector - White 16 Way
Cavity Circuit Function
1 N/C
2 D25 20VT/YL PCI BUS
3 N/C
4 Z12 20BK/TN GROUND
5 Z12 20BK/TN GROUND
6 N/C
7 D21 20PK SCI TRANSMIT (PCM)
8 N/C
9 D24 20WT/DG FLASH PROGRAM ENABLE
10 N/C
11 N/C
12 D20 20LG SCI RECEIVE (PCM)
13 N/C
14 N/C
15 D15 20WT/DG (EATX) SCI TRANSMIT (TCM)
16 A14 16RD/WT FUSED B+
Notes:
- EATX = Auto Transmission
- TCM = Transmission Control Module (Used on Auto Trans)
- Flash Program Enable = This is Chip Enable. Either taking this pin HI (5V) or LO (GND) will allow PCM Upgrade to be loaded. Avoid this pin unless you have verified this 3 ways from Sunday and are completely comfortable with "Flash Upgrade" procedure. This could render the PCM useless if the Flash isn't done properly.
- In the Circuit column, the first 3 designators (eg. D25) indicate the Circuit and where the connector is located, and the 2nd field (eg. 20VT/YL) indicate the wire gauge and color.
On Manual Transmission cars, there should be no extra circuit overhead needed to differentiate between pin 7 and 15 to deal with the TCM.
We can assume that if Chrysler changed the Pinouts in mid stream, they also deviated from Standard OBDII datastream interpretation, and introduced "Enhanced Parameters" to the mix. From what I can ferret out, they have gone with the General Motors VPW protocol; however, neither General Motors, Ford or Chrysler show a p1188 error code description on any of the online error code look-up tables that I have been able to find.
This may be another pointer to the effort that Chrysler made to obscure the data long enough to sell a corrected PCU to the customer as an "Upgrade" for primo bux....
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