Good power source MQ exceed

[Greytriton]

I've recently fitted 2 accessories which required 12V power, ignition power and earth. They are the boost gauge and throttle controller. For convenience I used the power from the pins of the OBD2 plug. Works just fine but I'm wondering if it's the source of my infrequent U3FFF error message.

As this truck is push button start, can anyone recommend a more suitable easy to get at source of power for these devices. The OBD2 plug location was simply the most convienient.

Anyone have a schematic I can use?

[Greytriton]

I think I found my answer.

The diagnostic socket has a dedicated 15A fuse to pin 16 from F12.

So should be plenty of uninterrupted juice.

[Greytriton]

Now I need to find the power source which pin on the diagnostic socket is ignition switched. Currently connected accessories power there also.

Looking at the supply though on pin 16 basically you can power some ok shit there. What I did was attach the wires on the rear of the diagnostic socket by stripping some insulation and soldering. Then the diagnostic socket is still available to use for example with the scan gauge.

I think the error I have U3FFF is related to the full EGR block.

Can anyone shed any light on U3FFF?

[Cowboy Dave]

I wouldn't be connecting anything at all where you have. The canbus/obd setup is very voltage sensitive. If your dealer tries to reflash/update your ECU and cops an unexpected voltage drop it is unlikely to end well.

On the previous models there were several vacant slots for relays that had ignition/accessory/constant power which could be accessed with a standard blade crimp pushed in the open slots.

[RHKTriton]

The words 'diagnostic socket' should say it all!

There are usually quite a few spare sources on the fuse block.

A much safer way to tap sources for your requirements is to use the piggy-back fuse units that
plug into an occupied position and provide a fused tail as well as maintain the original fuse.

[Greytriton]

Yes I understand what your saying but the pin 16 is a direct line to F12 15A supply so is not in connection to the CAN circuit. It's only diagnostic equipment supply.

Either way I put a plug socket as any accessory bar the tachometer would be removed at service time.

I do however would feel safer with an alternative supply