Data Link Connector Diagnosis Or No Scan Tool Data

NOTE: Perform On-Board Diagnostic (OBD) system check after completing any repairs. See ON-BOARD DIAGNOSTIC SYSTEM CHECK .

Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC SYSTEM CHECK . After performing OBD system check, go to next step.
Turn ignition on, with engine off. Connect a test light between Data Link Connector (DLC) battery feed circuit and ground circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 4. If test light does not illuminate, go to next step.
Using a test light connected to ground, probe DLC battery feed circuit. See WIRING DIAGRAMS article. If test light illuminates, go to step 9. If test light does not illuminate, go to step 10.
Turn ignition on, with engine off. Using DVOM connected to ground, probe class 2 serial data circuit at DLC. See WIRING DIAGRAMS article. DVOM should read zero volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step 7.
Turn ignition off. Disconnect PCM harness connectors. Turn ignition on, with engine off. Using DVOM connected to battery positive, probe class 2 serial data circuit at DLC. See WIRING DIAGRAMS article. DVOM should read zero volts. If voltage is as specified, go to next step. If voltage is not as specified, go to step 8.
Check for open in class 2 serial data circuit between DLC and PCM. Repair as necessary. If circuit is okay, go to step 11.
Check for short to voltage in class 2 serial data circuit. Repair as necessary. If circuit is okay, go to step 11.
Locate and repair short to ground in class 2 serial data circuit.
Locate and repair open in DLC ground circuits.
Locate and repair open or short to ground in DLC battery feed circuit.
Replace PCM. Perform PCM relearn procedures.