8111870a

So my 96 GT is in my garage, engine and tranny out. Getting ready to install my new engine.
Preparing for a base tune for break-in, I need to return my XCal2 to stock.
How do I get power to the PCM/OBD in order to return it to stock from the custom tune?
I tried just the 12v + wires and a couple of the big grounds, I get some power to the car, but not to the OBD port.
What needs to be hooked up to power the port and the PCM?
thanks

BraMas

I assume you have the engine wire harness off. If you do plug that back into the firewall plug (big square one) and I believe there is a power wire that connects under the fuse box that has to be on. Or just wait untill you have the engine back in the car with everything connected and load the tune up than

cliffyk

Here are the PCM connections needed to "bench flash" an EECV PCM:



Note that PCM pin 55 is a hot-at-all-times +12V connection this should be powered on first, then wait 30-45 seconds for the PCM to boot up. Next power up (connect to +12V) PCM pins pins 71 and 97.

+18V must be applied to pin 13, this is supplied by the flash tool through pin 13 of the OBD2 connector.

Here is an OBD2 to PCM tool for test bench flashing EECV PCMs:



There is nothing special inside the box--just a +12V input jack (pin 55 is powered as soon as the +12V power is connected, a switch to power pins 71 and 97, and an female OBD2 connector (to connect the flash tool) wired as described above.

I have the schematic diagram if anyone is interested...

8111870a

Thanks guys!
That helps tremendously. cliffyk you are awesome!
cheers!

cliffyk

You can get an OBD2 female connector on a 12" pigtail here for $10, then pick up an EECV 104 pin connector from a junk yard and wire it all up as shown below:



It's shown in the diagram with the Main power (SW1) and PCM power (SW2) closed and both LEDs on, in practice however both switches would be OFF until the PCM was connected--NEVER connect a PCM to the interface if either LED is ON. Here's the full sequence:

1. Make sure Main and PCM power switches are OFF;
2. Apply power to the interface, use +12V from a battery or a 12V 1.0A "wall wart";
3. Connect the PCM to 104-pin EECV connector;
4. Turn Main power switch ON (green LED lights), and wait 30 to 45 seconds for the PCM to "boot";
5. Connect your tuner to the OBD2 connector, and prepare it as needed to flash a tune;
6. When the tuning tool asks you to turn the ignition key to RUN, turn the PCM switch ON (red LED lights);
7. The tuner will upload the new tune as usual;
8. Turn the PCM power OFF when your tuner says to turn off the ignition or after the tune is loaded, depending on your tuning tool

That's it, done it dozens of times...


================================================== ==
Note: there was an issue with the connector diagram in my previous posting--now corrected the SCP - and + pins were incorrectly identified as pins 14 and 15, they should have been and are now labeled 15 and 16.

8111870a

Thanks again cliffyk, loads of good info, as always!

04cobrabuild

Is this picture also good for an 04 cobra?



Note that PCM pin 55 is a hot-at-all-times +12V connection this should be powered on first, then wait 30-45 seconds for the PCM to boot up. Next power up (connect to +12V) PCM pins pins 71 and 97.

+18V must be applied to pin 13, this is supplied by the flash tool through pin 13 of the OBD2 connector.

Here is an OBD2 to PCM tool for test bench flashing EECV PCMs:



There is nothing special inside the box--just a +12V input jack (pin 55 is powered as soon as the +12V power is connected, a switch to power pins 71 and 97, and an female OBD2 connector (to connect the flash tool) wired as described above.

I have the schematic diagram if anyone is interested...[/QUOTE]