Scan Tool Does Not Power Up

Diagnostic Instructions Perform the Diagnostic System Check prior to using this diagnostic procedure: Diagnostic System Check - Vehicle Review the description of Strategy Based Diagnosis: Strategy Based Diagnosis An overview of each diagnostic category can be found here: Diagnostic Procedure Instructions Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
X84 Data Link Connector B+	1	1	—	—
X84 Data Link Connector Ground	—	1	—	—
1. Scan Tool Does Not Power Up

Circuit/System Description The X84 Data Link Connector (DLC) is a standardized 16 cavity connector. Connector design and location is dictated by an industry wide standard, and is required to provide the following: Scan tool B+ voltage at terminal 16 Scan tool ground at terminal 4 Common ground at terminal 5 Diagnostic Aids The scan tool will power up with the ignition OFF. Some devices however, will not communicate unless the ignition is ON and the power mode master device sends the appropriate power mode message. If the B+ circuit, ground circuits, and connections of the data link connector are functioning properly, the malfunction must be due to the scan tool. Reference Information Schematic Reference Data Communication Schematics Control Module References Connector End View Reference Master Electrical Component List Description and Operation Data Link Communications Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Testing

1. Ignition/Vehicle OFF, all access doors closed, all vehicle systems OFF, and all keys at least 3 m (9.8 ft) away from vehicle. It may take up to 10 min for all vehicle systems to power down.
2. Verify a test lamp illuminates between each of the X84 Data Link Connector ground circuit terminals listed below and B+. Terminal 4 Terminal 5 ⇒ If the test lamp does not illuminate Repair the open/high resistance in the ground circuit or ground connection. ⇓ If the test lamp illuminates
3. Ignition ON/Vehicle In Service Mode.
4. Verify a test lamp illuminates between the B+ circuit terminal 16 at the X84 Data Link Connector and ground. ⇒ If the test lamp does not illuminate and the circuit fuse is good 4.1. Test for an open/high resistance in the B+ circuit. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.2. Verify the fuse is not open and there is voltage at the fuse. ⇒ If the test lamp does not illuminate and the circuit fuse is open 4.1. Test for a short to ground in the B+ circuit. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 4.2. Refer to the scan tool user guide. ⇓ If the test lamp illuminates
5. Refer to the scan tool user guide.