DESCRIPTION & OPERATION
| WARNING | Vehicles are equipped with air bag supplemental restraint system. Before attempting any repairs involving steering column, instrument panel or related components, see SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG SYSTEM in AIR BAG RESTRAINT SYSTEM article in RESTRAINTS. |
| CAUTION | When battery is disconnected, vehicle computer and memory systems may lose memory data. Driveability problems may exist until computer systems have completed a relearn cycle. See COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION before disconnecting battery. |
There are two data lines that can be accessed with a scan tool. The 800 circuit data line is a Class 1 data line. It allows the Sensing and Diagnostic Module (SDM), HVAC programmer and Electronic Brake Control Module (EBCM) to communicate by transmitting data. The 835 data line is the data line that the HVAC programmer, HVAC control head and radio communicate on. A scan tool can be connected to the DLC, allowing the scan tool to communicate with the data lines. System operations can then be monitored for diagnostic purposes.
COMPONENT LOCATIONS
| Component | Location |
|---|---|
| Data Link Connector (DLC) | Behind Driver Side Of Instrument Panel, Right Of Steering Column. (Scheme 1) |
| Diagnostic Energy Reserve Module (DERM) | Below Driver Seat. (Scheme 2) |
| Electronic Brake & Traction Control Module (EBTCM) | Driver Front Of Engine Compartment, On Strut Tower. (Scheme 3) |
| HVAC Programmer | Behind Passenger Side Of Instrument Panel. |
| Powertrain Control Module (PCM) | Behind Passenger Side Of Instrument Panel. (Scheme 4) |
| Radio | Center Of Instrument Panel. |
| C200 (116 Terminals) | Behind Center Of Instrument Panel. (Scheme 5) |
| S226 | In Body Harness, Near DLC. (Scheme 1) |
COMPONENT LOCATIONS
Scheme 1
Scheme 2
Scheme 3
Scheme 4
Scheme 5
TROUBLE SHOOTING
- Check for an open or short in circuit 800, circuit 835 and circuit 1807. See «WIRING DIAGRAMS»(/buick/lesabre/vii-1992-1999/remont/communication-devices/#data-link-communications-system) .
- Visually inspect for obvious signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. These circuits may be intermittent or resistive when loaded and should be checked by monitoring the voltage drop with the system under load.
- Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary.
SCAN TOOL DOES NOT COMMUNICATE WITH A CLASS 1 MODULE
To perform diagnosis (Scheme 6)and (Scheme 7).
Scheme 6
Scheme 7
SCAN TOOL DOES NOT COMMUNICATE WITH AN ENTERTAINMENT OR COMFORT MODULE
To perform diagnosis (Scheme 8)and (Scheme 9).
