Resolved 1G No power to obd?

[mitsuowner1991]

Checked cig lighter fuse and it's fine. Any other ideas?

 

[rabenne]

The issue is somewhere between the last place you had voltage and the first place lost voltage.

So get out your meter and start following the circuit diagram. Check from one end to the other. It is between "last and lost".

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E-19 - DIAG CONN

 

[BLACK'98DSM]

I had a similar problem, turns out I had a loose ecu cable. Check those too since it's easy.

 

[steve]

Technically there isn't power to the 1G Diagnostic Connector. What are you trying to do/check?

 

[rabenne]

Interesting... thanks for the input Steve.
OP - https://www.ecmtuning.com/wiki/diagport-12pin

that talks a bit about the wiring of the diag port.

 

[steve]

There are other signals present on the DLC connector like the VSS, cruise control, and TCU is present but the ECMTuning like is correct W.R.T. the 1G ECU connections. The three pins are Data, Mode, and Ground.

The ECU uses pin 1 as a bidirectional data line. In the default mode the ECU outputs either current fault codes or a heartbeat on the data pin. In diagnostic mode (grounding the mode pin) the ECU switches to datalogger mode, inputting commands and outputting responses on the data pin. The ECU also uses the mode pin (and the timing check connector under the hood) for setting base idle speed and and setting the base timing via the CAS.

If the ECU doesn't output any voltage on pin 1 it's either not turned on (via the MPI relay) or it's dead.

See: https://www.dsmtuners.com/threads/1g-basic-ecu-mpi-circuit-function.435961/ for diagnosing this.