I was working on a bench top programming harness last week and took some pictures and notes in case anyone else wanted to make one. There's bits and pieces of information all over but I have yet to see it all in one spot? Procedure is about the same for all PCMs, need power to PCM, grounds and the serial connection. So with this setup you can cut the harness and add plugs to make more PCM plugs for different PCMs.
I've heard some horror stories of bricking a PCM when doing a full reflash in a vehicle with other modules connected to serial line interfering and seems the safe way is the bench top method. Just tune changes don't seem to be an issue. Heard of some pulling fuses to other module circuits. I don't know all the possibilities and maybe we can come up with a list of does and don't when it comes to full flash?
So this is for the 0411 PCM that comes in LS1 engine vehicles. They are a little different so watch the wiring! Only 4 -5 wires needed!
1997 - 1998 only all in the Blue PCM connector.
Blue Pin 21 Ground and OBDII 4 and 5 ground.
Blue Pin 20 and 61 +12v Orange wire OBDII Port 16
Blue Pin 19 IGN +12V Pink wire - key on.
Blue Pin 58 Serial Green to OBDII Port 2
1999 up 0411 PCM - LS1, LB7, Early V6 and 4 cyl
Blue Pin 19 IGN +12V Pink wire - key on.
Blue Pin 20 +12V Orange wire - OBDII port 16
Blue Pin 60 Ground Black White Stripe - OBDII Port 4 and 5.
Blue Pin 58 VPW Serial Data Green to OBDII Port 2.
OBDII ALDL wiring for GM, some wires are same on all cars and some are different per manufacturer and vehicle with more modules.
Vehicle OBDII Connector Pin Assignments
Vehicle OBDII Socket
SAE J1962 Female
1. GM CAN (Low-speed, Single-wire). Not used for benchtop harness.
2. Serial data. Used for bench top harness!
3. Pin assignments have been left to the discretion of the manufacturer. Not used.
4. Ground black wire (chassis ground). Used for bench top harness!
5. Ground black/white wire (Siganl Ground). Used for bench top harness!
6. ISO 15765-4 CAN High. Not used for benchtop harness.
7. ISO 9141-2 & ISO 14230-4 K-Line. Not used for benchtop harness.
8. Pin assignments have been left to the discretion of the manufacturer. Not used for benchtop harness.
9. GM ALDL (OBD-I 8192bps) Not used for benchtop harness.
10. SAE J1850-VPW Negative. Not used for benchtop harness.
11. Pin assignments have been left to the discretion of the manufacturer. Not used for benchtop harness.
12. Pin assignments have been left to the discretion of the manufacturer. Not used for benchtop harness.
13. Pin assignments have been left to the discretion of the manufacturer. Not used for benchtop harness.
14. ISO 15765-4 CAN Low. Not used for benchtop harness.
15. ISO 9141-2 & ISO 14230-4 L-Line. Not used for benchtop harness.
16. Fused battery feed orange wire. Used for bench top harness!
There's 12 volt power supplies used on some commercial bench top harness but I have always stuck with a 12 volt fully charged car battery. TunerCat warns not to use an AC charger on laptop when flashing a PCM in car. EFI Live warns no AC charger to flash as well in car (IIRC when V2 is grounded with external data like wide band). While others say to keep AC charger on laptop while bench top programming. Since I have always used a full charge battery on bench or checked charging system and battery in car, and always start with a full charge on laptop battery and never had an issue I'm sticking to that.
Flashing in car:
Vehicle: All accessories off, car alarms off, OnStar off.
Laptop: Screen savers off, power management off, virus protection off, do not interrupt!
Here's a good use for an old ECM as an electronics project box. 12 volt is needed to PCM at all times, 12 volt is also needed to Ignition 12 volt power to PCM, some tuning flashes can be done without this but not a full program or VIN number change, this change is saved in vehicle PCM when key is turned off and 12 volt power is still applied. So in keeping with programming just like in a car we have Key On Power like the key switch.
I used lighted switches so I can see power on and key on.
Main power switch gets power and sends it to Pin 20 or 20 and 61 of blue PCM connector and to Key On switch and to OBDII Pin 16.
Key on power switch sends power to blue PCM connector Pin 19
Ground blue PCM connector Pin 21 or 60 and
Ground OBDII ALDL port 4 and 5.
Ground lighted switches.
Serial data from blue PCM connector to OBDII Pin 2
A look at inside wiring.
All done and ready for back cover and mount on the wall.
Here's the finished equipment ready for bench top programming. Up top is one I built awhile ago for LT1 PCMs.
Reply With Quote
Bookmarks