Instruments cease to function obd2

hardware installation for the RaceCapture Plug & Play, including custom installations
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drcbike
Posts: 3
Joined: Thu May 24, 2018 5:37 am
Location: Goodyear, az

Instruments cease to function obd2

Post by drcbike »

Installed RC track. All can bus instruments (speedo, tach, fuel level and water temp) cease to operate when obd2 adapter is plugged in.
2005 lotus Elise. Basically a 2004 celica engine and ems.

RC track cable can be disconnected and instruments still don't work. Issue appears to be the obd adapter.

Suggestions?
-drc-
Don Clinkinbeard

brentp
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Post by brentp »

Hi,

We can help. Do you have the legacy OBDII adapter, or the regular CAN cable? Also, when you say "CAN bus instruments" - you mean the gauges in the RaceCapture app, or the actual physical dashboard of the vehicle?
Brent Picasso
CEO and Founder, Autosport Labs
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drcbike
Posts: 3
Joined: Thu May 24, 2018 5:37 am
Location: Goodyear, az

instruments cease to function obd2

Post by drcbike »

Legacy OBD2 adapter that came with the unit.

The cars dash instruments cease to operate. The data shows up in the race capture display.
-drc-
Don Clinkinbeard

brentp
Site Admin
Posts: 6281
Joined: Wed Jan 24, 2007 6:36 am

Post by brentp »

Ok, that is curious. So, you can get data in the RaceCapture app such as RPM, TPS, and so on, but you instruments stop functioning.

The Lotuses of that year have an interesting hybrid system of legacy OBDII protocol support, but with also the CAN bus wires connected, which provides a feed of data from the ECU (going to the dashboard).

We talk about it quite a while ago here:
https://www.autosportlabs.com/pre-obd-i ... -can-data/

RaceCapture makes CAN bus requests to the legacy adapter, and then the legacy adapter translates it to legacy OBDII calls.

The CAN bus requests is also present on the CAN bus pins on the OBDII connector, and nearly all pre-CAN bus cars *do not* have these pins connected, so there's no issue.

It seems that the messages coming from RaceCapture might be conflicting with the data going to the instrument cluster.

We have a couple of options:

1) disconnect the CAN bus pins in your OBDII connector underneath the dash, so the CAN messages from RaceCapture cannot be seen by the ECU, which would prevent any conflicts.

2) Disable OBDII and only use the data provided by the ECU to the instrument cluster, as described in that blog post (above).

In the meantime, please try this:

connect the OBDII adapter, but turn off the OBDII feature under setup. Don't delete your channels, simply turn the switch to Off and then write the settings.

This should prevent CAN traffic from going to your car.

When you do this, let me know if your instrument cluster comes back to life, even if you're otherwise plugged in.
Brent Picasso
CEO and Founder, Autosport Labs
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drcbike
Posts: 3
Joined: Thu May 24, 2018 5:37 am
Location: Goodyear, az

Post by drcbike »

(In the meantime, please try this:

connect the OBDII adapter, but turn off the OBDII feature under setup. Don't delete your channels, simply turn the switch to Off and then write the settings.

This should prevent CAN traffic from going to your car. )


ok Brent, RPM and fuel level (and i suspect the rest) come back on the instrument panel when I turn off the obd2 function. RCT does not show the instrument cluster data under this condition.
-drc-
Don Clinkinbeard

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