DLC Diagnosis Or No Scan Tool Data

WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.

Perform On-Board Diagnostic II (OBD-II) System Check. See ON-BOARD DIAGNOSTIC II (OBD-II) SYSTEM CHECK in SELF-DIAGNOSTICS - INTRODUCTION article. After performing OBD-II system check, go to next step.
Install Tech 2 scan tool on known-good vehicle. If scan tool display VCM data, go to next step. If scan tool does not display VCM data, go to step 17
Reconnect scan tool to vehicle DLC. Turn ignition on. If scan tool powers up, go to next step. If scan tool does not power up with ignition on, go to step 8.
Using scan tool, monitor Class II messages. If all modules on serial data circuit communicating, go to next step. If any module(s) on serial data circuit fails to communicate, go to step 6.
Using scan tool, check Class II Diagnostic Trouble Codes (DTCs). If any DTCs are stored, diagnose DTC. See SELF-DIAGNOSTICS - INTRODUCTION article. If no DTCs are stored, check for faulty fuses. Check for loose, corroded or damaged connectors or wiring harness. Repair or replace as necessary and retest system.
Check for VCM communication. If VCM is not communicating, go to next step. If no problem is found, see SELF-DIAGNOSTICS - INTRODUCTION article.
Turn ignition off. Disconnect components sharing serial data circuit, leaving VCM harness connectors connected. See SYSTEM WIRING DIAGRAMS article. Turn ignition on. If scan tool does not display VCM data, go to step 12. If scan tool displays VCM data, problem is intermittent. Check wiring harness and connectors for looseness, damage and corrosion. Repair or replace as necessary.
Using test light connected to ground, probe DLC connector terminal No. 16 (Orange wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 11.
Using test light connected to battery voltage, probe DLC harness connector terminal No. 4 (Black wire). If test light illuminates, go to next step. If test light does not illuminate, go to step 15.
Using test light connected to battery voltage, probe DLC harness connector terminal No. 5 (Black/White wire). If test light illuminates, go to step 17. If test light does not illuminate, go to step 15.
Check PWR AUX fuse in instrument panel fuse box. If fuse is open, go to step 13. If fuse is okay, go to step 14.
Inspect class II serial circuits for opens or poor connections. If problem is found, go to step 16. If no problem is found, go to step 18.
Locate and repair short to ground in Orange wire between PWR AUX fuse and DLC. See SYSTEM WIRING DIAGRAMS article. Replace fuse and go to step 20.
Locate and repair open in Orange wire between PWR AUX fuse and DLC. Replace fuse and go to step 20.
Locate and repair open Black wire between DLC and ground. After repair, go to step 20.
Locate and repair opens or poor connections in class II serial data circuits. After repair, go to step 20.
If scan tool does not display VCM data, Scan tool or cables are faulty. See scan tool manual for repair instructions. After repair, go to step 20.
Check for poor connections in class II serial data circuit (Dark Green wire) at VCM and DLC harness connectors. Repair as necessary. If repair was necessary, go to step 20. If no repair was necessary, go to next step.
Replace VCM. Program replacement VCM. Perform VDT password learn procedure. Perform CKP sensor variation learn procedure. See PROGRAMMING . Retest system.
Using scan tool, display CAPTURE INFO. Review CAPTURE INFO functions. If no DTCs are displayed, system is okay. If DTC(s) is displayed, go to testing procedure for affected DTC to diagnose problem. See SELF-DIAGNOSTICS - INTRODUCTION article.