What I say is, that technically seen I would first replace the the
oxygen sensor again, as this is a most probable cause of the problem.
Then I say, that the OVP relay is not impossible to cause the problem,
and you could chance to replace that first (it costs only half, but in
the end, it may have cost you one and a half).
You never know how long time things last. Both items will normally have
a very long lifetime, but if something is wrong with them, the fault
will typically appear in the beginning of their lifecycle (if it is a
new origininal item, warranty should cover).
You can also try to troubleshoot (if you have the means) by measuring
the the oxygen sensor signal at the input to the computer. When engine
is running correctly, the voltage should fluctuate between 0,2 and 0,8
In your case the voltage should go towards 0,8 volts to indicate too
- If so, you should suspect the EHA or the wiring to it.
- If not (the voltage is near 0 volts), you shold suspect the oxygen
sensor or the wiring (short circuit or open) to it.
The above assumes that supply voltages to the computer are OK (through
the OVP relay).
To measure inputs/outputs of the computer, you can take the computer
out of its case, put it on so it is isolated from chassis (on a piece
of cardboard) and reconnect the cable. The pins from the plug can be
measured at the printed circuit board. The oxygen sensor input is pin
Be careful not to harm the computer.