Bench Flashing OBD II LT1??

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01-12-2014
dave w

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Bench Flashing OBD II LT1??

I'm wondering if anyone has a write up / pin out for building an OBD II LT1 Bench Flash tool? I'm curious because the OBD II schematics (attached below) shows two Serial Data pins (C4) Blue 7 and (C4) Blue 30. I've noticed (C4) Blue 20 is an Output / Field Service Enable is connected to the ALDL Connector. I'm not sure if (C4) Blue 20 is needed for bench flashing an OBD II LT1 PCM? I'm not sure if (C4) Blue 20 and (C4) Blue 30 are needed for bench flashing an OBD II LT1 PCM?

If the OBD II schematics (attached below) are correct, then Bench Flashing the LT1 OBD II PCM needs the following pins connected to the PCM?

(C2) Black Pin 15 Battery
(C2) Black Pin 30 Switched Ignition
(C2) Black Pin 31 Battery

(C4) Blue Pin 01 Ground
(C4) Blue Pin 03 Switched Ignition
(C4) Blue Pin 07 Serial Data

The links below are to the bench flashing tool offered by EFI Connections:
http://www.eficonnection.com/eficonn...spx?ItemId=716

http://www.eficonnection.com/eficonn..._extension.jpg

I'd like to build my own, and save a few $$!:thumbsup:

dave w
01-12-2014
EagleMark

2 Attachment(s)

These are from TC and someone that came over when Monodax died had donated them. Thanks to (I forget who?)!
01-12-2014
dave w

Quote:

Originally Posted by EagleMark

These are from TC and someone that came over when Monodax died had donated them. Thanks to (I forget who?)!

Thanks Mark!:thumbsup:

The only difference I see with my pin out posted above vs. the .pdf pin out is (C2) Back pin 6, which in the schematic I posted is a reference ground for the TPS and transmission temperature sensor. I don't see any concerns adding ground to (C2) Black pin 6.

dave w
01-13-2014
Buzz

Quote:

Originally Posted by dave w

... shows two Serial Data pins (C4) Blue 7 and (C4) Blue 30 ... I'm not sure if ... (C4) Blue 30 are needed for bench flashing an OBD II LT1 PCM? ...

I believe the following is true ... however, I work with LSx engines only ... I don't touch the LT1 ...

C4 pin 7 is Serial Data to the DLC. C4 pin 30 (and probably pin 29) are UART coms - these are typically coms with a TAC module or a traction control system
01-13-2014
EagleMark

My bench flash wiring for OBDI LT1 is to serial. I was told this is wrong by a well known tuner who had published info as to it going to the other pin, but it has been working for years that way. When I looked at wiring diagrams it was corrrect and the other wires (UART?) were wired to other modules first then PCM.