This is how to read the ECS trouble codes with an analogue voltmeter on a OBD1 3000GT,
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Find the datalink connector under the dash in the driver’s side.
A. 1ST GENERATION - connect + to pin 3, - to pin 12. Pin 3 is the third down on the left side, before the double space. Pin 12 is the lower right corner.
B. 2ND GENERATION - connect + to pin 3, - to pin 4 or 5. Pin 3 is the third from the top left side of the connector ( on the log side of the trapezoid), pin 4 and 5 are next to the right. -
Turn the ignition on.
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Look at the voltmeter. The code is repeated many times. Seven (7) short deflections is code =0, and means everything is wonderful.
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Other codes are: 1 long, 1 short = 11, G sensor bad.
2 long, 1 short=21, steering angular velocity sensor open
2 long, 4 short=24, speed sensor open
These codes don’t disappear until ingnition switch is off, even if you fix the problem.
- These codes disappear when you correct the problem:
6 long, 1 short=61, Front Right shock
6 long, 2 short=62, Front left shock
6 long, 3 short=63, Rear right shock
6 long, 4 short=64, Rear Left shock
MFI trouble codes are read in a similar manner, but different pins.
FIRST GENERATION - connect + to pin 1, - to pin 12.
SECOND GENERATION - Connect pin 1 to GROUND and watch the CHECK ENGINE light flashes for same sort of patterns - long flashes (1.5 sec) are tens digit, short (0.5 sec) flashes are ones digit. That gets you the same codes you would read on the Scan Tool.
You clear codes by disconnecting the battery for 10 seconds, reconnecting and idling the car for 15 min to make sure the codes don’t return
Contributed by ajudd
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Remove any serial diagnostic lead you have connected before you start!
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Set your multimeter to 20V, as the pulses are 10V each and this way you get a very clear reading
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Best way to get your multimeter to stay connected without having to hang upside down your steering column while doing this is to a. slide the diagnostic port backwards off of it’s mounting clip - this gives you about 10 cm of lead and b. buy 2 micro crocodile clips and then ‘crimp’ these onto the end of your multimeter
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Do 3. Means you can stand outside the car and check the readings while changing things
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Once you’ve fixed the problem you’ll need to disconnect the battery for 20 seconds to reset the codes. I know the original post said they will go away automatically but on my '91 they stayed until reset.
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Test your wiring loom using a multimeter on ‘connectivity beep’ mode. This is a great way of making sure all the wires reach where their meant to be going. Disconnect the plug from the top of the shock, disconnect the other end from the big square connector, insert a paper clip or safety pin into one of the micro sockets on the shock end and test the matching end with the other multimeter probe.
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If you don’t want to unbolt your suspension to remove the caps you can just prize off the plastic covers rather than unbolting the whole suspension.
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The wiring sequence for the little plugs that go into the top of the front shocks is
Blue
Black Green
White Red
where the Blue wire goes in the back of the plug where the vertical ‘notch’ is and going clockwise around the order is Blue, Green, Red, White, Black.
Hope this helps!
Alex
Contributed by 3000GT_PILOT
in addition to what has been written up there ^^^^^ i have drawn a little diagram of the strut wiring loom connections. sorry it had to be done on “paint”
EDIT: THIS IS AS IF YOU WERE LOOKING AT THE FRONT OF THE PLUGS
1994 3000GT TT, in the best colour…
RED ONES ARE FASTER