Poor Navigation Radio Voice Recognition Performance - keywords inoperative microphone onstar

This PI was superseded to direct GMTAC chassis/electrical consultants to forward the case to the GMTAC OnStar team for parts handling. Please discard PIC4745A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Some customers with Navigation Radio (U3R) on a 2008 Cadillac DTS may report poor or no operation of the navigation radio voice or speech recognition system when using the "push to talk" button on the steering wheel controls. The system may fail to detect the command or will confuse the command, thus responding as something other than what was requested by the user. The customer may also report that the OnStar voice recognition when using the hands-free calling (White Phone Icon) button on the inside rear view mirror assembly works properly. This will indicate that the concern is isolated to an internal audio pass-thru function within the OnStar module and not the fault of the navigation radio, microphone or its inputs.

Significant voice or speech recognition improvements can be achieved by installing a 220 ohm resistor in series of the audio output signal circuit (#7043 (gray/blk)) from the OnStar module (VCIM) to the Navigation Radio System. A pre-assembled pigtail, along with detailed instruction can be obtained by contacting GM Technical Assistance who will ship one as needed to those dealers that have a customer condition/concern as outlined above and for the vehicle/RPO application(s).

A technical service bulletin is in development.

Note: Any addresses or Points of Interest (POI) stored prior to the modifications to the audio output circuit MUST be deleted and re-stored to insure improved overall performance

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.