Electronic Transmission Range Selector Description

The Electronic Transmission Range Select (ETRS) subsystem selects the transmission range (Park, Reverse, Neutral, Drive, or Manual) by means of electronic control rather than by mechanical means. The ETRS feature is controlled in the Engine Control Module. All Transmission Range Selector Controls and Transmission Range Control Module DTC's will set in the Engine Control Module. The Engine Control Module communicates via HS GMLAN and the Powertrain Expansion Bus.

Transmission RPO: M3H

When a gear is selected, the Transmission will shift into the range commanded by the ETRS system. The ETRS system components will communicate on HS GMLAN and Powertrain Expansion Bus.

The Backup Park Lock functionality is internal to the Transmission, and forces the transmission into Park position under specified conditions. Under these conditions the vehicle is put in Latent Fault Mode, refer to Latent Fault Mode Description .

The A97 Transmission Range Selector Controls in the ETRS system has no mechanical linkage to the transmission. Instead, the A97 Transmission Range Selector Controls will provide electrical signals based on customer input to the Engine Control Module, where the customer shift request will be determined.

A97 Transmission Range Selector Controls Assembly includes:

• Park Button - Park button has two internal contacts. Single push button. Normally open switch that is closed when the button is pressed. Actuation is one push.
• Reverse Button - Reverse button has three internal contacts. Single pull button. Normally open switch that is closed when the button is pressed. Actuation is one pull.
• Neutral Button - Neutral button has three internal contacts. Single push button. Normally open switch that is closed when the button is pressed. Actuation is one push.
• Drive Button - Drive button has three internal contacts. Single pull button. Normally open switch that is closed when the button is pressed. Actuation is one pull.
• Manual/Low Button - Manual/Low button has one internal contacts. Single push button. Normally open switch that is closed when the button is pressed. Actuation is one push.

The vehicle is equipped with the following Electronic Transmission Range Selector Components: 

• A97 Transmission Range Selector Controls
• K20 Engine Control Module
• K71 Transmission Control Module