Body Function Controller (BFC) Diagnostic System Check
CAUTION:
Body Function Controller (BFC) Pink 24-pin connector C3 contains power and ground sources. When removing BFC, always disconnect connector C3 first before disconnecting connectors C1 and C2. When installing BFC, always reconnect connectors C1 and C2, then connector C3 last.
- Connect scan tool to DLC. If scan tool can be powered up, go to next step. If scan tool does not power up, go to SCAN TOOL INOPERATIVE .
- Attempt to communicate with Body Function Controller (BFC). If scan tool communicates with BFC, go to next step. If scan tool does not communicate with BFC, go to step 4 .
- Check for BFC DTCs. If DTCs exist, perform appropriate test under DIAGNOSTIC TESTS. See BFC DTC DEFINITIONS table under SELF-DIAGNOSTIC SYSTEM. If more than one DTC exists, start with lowest number of DTCs. If no DTCs exist problem may be intermittent. Check for poor connections, poor grounds or faulty circuits.
- Using scan tool, attempt to communicate with other modules along the class 2 serial data line (PCM, IPC, etc...). If scan tool communicates with other modules, go to next step. If scan tool does not communicate with other modules, go to SCAN TOOL DOES NOT COMMUNICATE WITH COMPONENTS .
- Check BFC BATT fuse (10-amp) located in left instrument panel junction block. If fuse is blown, go to step 11 . If fuse is okay, go to next step.
- Turn ignition switch to LOCK position. Disconnect BFC connector C3 and remove connector combs. Using test light backprobe between ground and BFC connector C3 terminal B1 (Orange wire). See WIRING DIAGRAMS . See Fig 1 . If test light comes on, go to next step. If test light does not come on, go to step 12 .
- Using test light connected to battery voltage, backprobe BFC connector C3 terminal B10 (Black/White wire). If test light comes on, go to step 9 . If test light does not come on, go to next step.
- Repair open in Black/White wire between BFC and ground. After repairs, go to step 16 .
- Using DVOM, measure resistance in Purple wire between BFC connector C3 terminal B2 and DLC terminal No. 2. If reading is 5 ohms or less, go to step 15 . If reading is greater than 5 ohms, go to next step.
- Repair open in Purple wire between BFC and DLC. After repairs, go to step 16 .
- Repair short to ground in Orange wire between left instrument panel junction block and BFC. Replace BFC BATT fuse. After repairs, go to step 16 .
- Using test light connected to ground, probe both sides of BFC BATT fuse. If test light comes on at both sides, go to next step. If test light does not come on at both sides, go to step 14 .
- Repair open in Orange wire between left instrument panel junction block and BFC. After repairs, go to step 16 .
- Replace left instrument panel junction block. After repairs, go to step 16 .
- Replace BFC. See BODY FUNCTION CONTROLLER (BFC) under REMOVAL & INSTALLATION. After repairs, go to next step.
- Reconnect all disconnected components and connectors. Using scan tool, clear any DTCs. If any DTCs reset, preform appropriate test under DIAGNOSTIC TESTS . If DTCs do not reset, system is okay at this time.