billybaloneey

My 2017 owners manual...in the "Add-On Electrical Equipment" section says that an after market device such as a driver-behavior tracking device...aka...an OBD II module...connected to the DLC (Data Link Connector) port...may interfere with the vehicles systems. Before loosing my 2005 to the hurricane Harvey flooding...I used several different OBD II devices...one of which was the ELM bluetooth module for an Android app called Torque.

Wondering if anyone has had any problems using such a device plugged into the DLC (OBD II) port under the dash? Any first hand 2017 knowledge on the subject would be welcome.

(If this is something more oriented to the C7 techies...I'll remove this post)


Thanks,
Clint

Flame Red

I do not have a 2017, but I will tell you that many folks have reported OnStar diag reports stop working with some OBD2 modules, like the Range AFM disabler for example. Many threads here regarding the Range and the many problems (limp home mode) on the '17 model year.

I have one of the BT Code Readers that I use with Torque, but I only plug that in when I need to read or clear a code. I doubt that it will cause any issues as it does not insert stuff on the GM Bus normally.

I also have a Window Valet and never an issue with that I suspect because it only inserts when the engine is off and the bus in not busy.

One suggestion is to unplug all such modules before bringing the car for service.

eboggs_jkvl

I have a mods4cars convertible Smarttop control plugged into my DLC and has been for at least 6 months. I get my monthly OnStar reports and I have seen no hint of an issue with the product. The Range thing is an entirely different animal and I read it tosses DTC codes.

That's all I got on this.

Elmer

dmhines

I saw this issue in my 2012 Mustang with Ford Health reports. Devices that simply read data on Canbus will be no problem. But devices like Range are actually inserting a data stream onto the Canbus can definitely cause anomalies.

JonMN

Ditto on both points. No problem with the mods4 cars but routine problems with Range.

Bill Dearborn

The key word is may. Some devices are better designed and built than others. You are plugging it into a systems bus and it is expected to obey the bus electrical and software data link rules. If you plug in one and it screws up the bus some systems may not work properly. Same is true for all cars with a data link not just the C7.

Bill

Dethsupp0rt

I've had the occasional quirk with mine. I, too, use Torque with a OBDII bluetooth adapter. It works most of the time, but I occasionally get weird issues like a hunting idle, or even warning messages on the dash (last time was something relating to the suspension).

It's probably not advisable to have something plugged in all the time.

Steve Garrett

I have a Window Caddy in my port full time-nothing has ever happened with my C7.

DrDyno

I bought my 2014 in October of last year with 8400 miles on it, and opted for limited OnStar service, which I've had ever since. I have yet to receive a diagnostic report. Are the diagnostic reports mileage driven? I've only put 3,000 miles on the car since I bought it.

Additionally, for the past month, I've had a Range (V-8.2) plugged into my OBDII port all the time. I've noticed NO anomalies with the Range plugged in. The car is on a battery tender every night so I also have no fear of the Range draining the battery.

LT1 Z51

Depends on what the devices are doing?

Are they reading CAN Bus Messages? Are they sending CAN Bus Messages? Are they trying to "spoof" existing CAN Messages (this can cause Message collisions). Are they even on the CAN Bus? Are they always powered (and therefore causing battery drain)?

Speaking of these devices, once every OEM implements full Cyber Security measures they will be worthless. Every OEM is isolating the internal CAN Bus from the OBD-II Connector, only leaving a "diagnostic" CAN Bus to the first module (either a Gateway or BCM) which then "transfers" the messages to the real CAN Bus. Since that device can typically only forward back and forth the diagnostic range spoofing modules will no longer be possible thru the OBD-II port. Mercedes and Chrysler already do this today with some limited success.

Expect the CAN bus to no longer be accessible to non-OEM approved products in the near future. Well not without tapping into it some other way, assuming the message you are spoofing doesn't have CAN security on it (that's coming too).

Gearhead Jim

I've recently started using the Valentine radar detector "Savvy" connector which plugs into the OBD port on our 2017. It provides switched power for the detector, and it reads the vehicle speed so the Valentine will mute any warnings when driving below a speed I set. Supposedly it isn't sending any information "into" the car, just looking at the speed output and taking a little electricity from the port.

My most recent OnStar diagnostic report said they couldn't do the diagnostics and maybe I had something aftermarket plugged in, like those devices provided by insurance companies. Yep, kinda.
I am not bothered that OnStar can't read the car, if that's the only issue.

Valentine's website says:
SAVVY draws a small current from the car battery even with the ignition switched off. Use caution in vehicles with weak batteries, or that go for long periods without being driven.
• OnStar® cannot run its full diagnostic test if SAVVY or any other device is plugged into the OBD port. SAVVY does not interfere with any other OnStar function.
• Click here for a list of cars with SAVVY compatibility issues. (Note: No GM vehicles or Corvette on that list, except electric vehicles)


With the understanding that these devices may cause other problems, I'd be interested in more reports from members about what they have plugged in and what is or isn't going wrong.

Does it help to periodically unplug the device, either to prevent problems or remove problems that crop up?
If problems come up, what are they and what do you do to fix them?

I think the Range AFM disabler is more intrusive, because it's telling the car to do something instead of just "listening", and that something is different from what the car normally does.

Further comments about your actual experiences are appreciated...

george vee

I have this plugged in for 10,000 miles without issues

Zymurgy

That's just not true. I've had my Window Valet plugged in for over 2 years and I get my OnStar Diagnostics Reports without fail.

Gearhead Jim

Well, I'd rather have them be too cautious with their warnings than too confident.

joemessman

I have that Torque app with my bluetooth diagnostics and no problems. You will notice they use the verbage "may" cause problems.

Avanti

No loss with missing OnStar reports, in my opinion, if that's all you lose.