Cutting the diag/idle trimpot out of circuit w/ fitting USB

[RB30-POWER]

Hey Guys/Matt

In your instructions you state to cut/remove the idle/diag trim pot when installing USB socket on these type 1 boards.

I done a test and when the pot is full counter clockwise the trim pot is 0 ohm resistance and more when rotated clockwise to add idle rpm and eventually entering diagnostic mode.

In diagnostic mode there is a 25rpm added to base idle rpm.

Would it be better to just join the wires when removing pot to keep the lower idle, as it should be set in the software anyway.

Or do you need to keep the ecu in diagnostic mode to retrieve the fault codes in the software?

I joined the two wires when i installed the board, but haven't actually looked if I can retrieve the fault codes throught the software yet.

Regards
Mick

[Matt]

Up to you. Depends how you wish the LEDs to be configured...

When you leave open you get DTC codes on the LEDs, but you get those in software anyway

When you close you get the normal O2 reported mixtures (as per factory manual) using the LEDs. But you get O2 sensor reported on software too but as a raw voltage

The idle RPM change is so minimal that you dont notice it that much anyway. On the bench I prefeer DTC codes (also handy if you got stuck somewhere and needed to find out because of dodgy AFM/CAS)