We have a transformed car, a Bentley, which no longer has a motorized sunroof. The blind has also gone. However the car diagnostics exhibits a fault on the related, non-present devices and motors. We are using ODIS 5.0.6 to read from the car computer diagnostics but are lacking experience in that field. Is there a way I can remove the options from the car computer without having to keep the steppers as dummies?

  • I would bet the only way to do it would be to get it "tuned out" ... that means getting the computer tuned so as to not recognize these options. More than likely they are only soft "switches" which tells the computer to check for such things. You'd have to find a tuner who could do this ... I'm thinking they'd be fairly sparse for a Bentley. Another option might be to get a computer for a Bentley which doesn't have this option. I don't know how you'd go about getting either, so leaving as a comment. Jan 19, 2015 at 18:49
  • Thanks Paulster2. Fact is Bentley "universe" is rather proprietary and conservative so indeed tuners appear to be quite sparse like you said. Grabbing another computer is not an option due to time constraints though. My take is that official dealers must have what it takes to either disable or delete the appropriate options, i.e. the soft switches you mentioned. I'll post here anyway if I ever get the info by other channels. Thanks for the hint.
    – user9147
    Jan 20, 2015 at 9:03
  • As per new information I grabbed, even Bentley technicians are not able to disable any options. I've been told they have to ask the headquarters for an authorization to make the required change... Looks like so far we need to hope these faults won't prevent the car from running properly.
    – user9147
    Jan 20, 2015 at 9:37
  • I think your best bet is to go back to utilizing the steppers as you suggested in your question. Jan 20, 2015 at 12:18
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    From a quick Google search it appears that at least some Bentley cars use the VAS 5xxx (the Volkswagen official diagnostic tool), you may try buying a third party implementation of that device and see if you can manually recode the related ECU. disclaimer: though I often mention that product I have no affiliation with them, I'm just a satisfied owner of their product
    – user5106
    Mar 8, 2015 at 23:08

1 Answer 1


This may or may not apply to the Bentley

In general, stock ECU's are not programmable from an options standpoint. Writing to the ECU is not allowed, they are read only. Aftermarket ECU's take output from sensors and frequently stand in serial to the stock ECU so the aftermarket can modify information and act as a proxy to the sensor, essentially emulating the sensor and sending the ECU information that will thereby increase fuel from an injector and what not to increase HP, as an example.

Clearly, there is a safety issue allowing consumers and/or mechanics to modify the ECU as it may control factors that are related to a safe driving experience. The associated liability for a manufacturer is simply to high for a manufacturer to be motivated to risk allowing these modifications.

I know of no stock ECU that allows a write, even for a configuration file (which isn't to say that this doesn't exist). Modifying a field or 'feature' for an ECU is also something I have not heard of.

I do not see the feature you are wanting to disable regarding the monitoring of the sunroof motor having an impact on the operation of motorized mechanical inputs from the ECU coming into play.

I have taken ECU's for BMW and Mercedes and put them into vehicles that don't have the ancillary features of the previous vehicle. Such as a sunroof,etc. I have had no issues with this.

Again, I have no knowledge about the Bentley configuration specifically.

  • Thanks for the detailed insight. However I can say Mercedes ECU can be programmed and some options removed through Xentry, for instance. Provided you have the proper licence you can remove non-critical options like sunroof motors. We just have no such "grant" with Bentley. A CAN filter would then seem the most logical option though not the easiest.
    – user9147
    May 1, 2015 at 20:41

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