Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Scan Tool Does Not Power Up: Description
Data Link Connector (DLC) provides operating voltage for scan tool at terminal No. 16 (Orange wire) and ground at terminal No. 4 (Black wire). DLC provides serial 2 data signal data at terminal No. 2 (Purple wire) and signal ground at terminal No. 5 (Black wire). Scan tool should power up with ignition switch in LOCK position, although many modules will not communicate unless BCM detects ignition ON signal and send appropriate power mode message.
- Check CIGAR/DLC (15-amp) fuse located in fuse block. If fuse is blown, go to next step. If fuse is okay, go to step 3 .
- Replace CIGAR/DLC (15-amp) fuse. Recheck fuse. If fuse is blown, repair short to ground in Orange wire between DLC connector terminal No. 16 and fuse block. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. If fuse is okay, go to next step.
- Check continuity between ground and DLC terminal No. 4 (Black wire). See Figure . If continuity exists, go to next step. If continuity does not exist, repair open or high resistance in Black wire between DLC and ground.
- Check for poor terminal contact at DLC connector terminals No. 4 (Black wire) and No. 16 (Orange wire). Repair as necessary. If terminal contact is okay, go to next step.
- Connect scan tool to another vehicle. If scan tool operates on another vehicle, check for poor connection between scan tool and DLC. If connection is okay, check for faulty scan tool. See scan tool manufactures instructions and repair as necessary. If scan tool does not communicate with another vehicle, check for faulty scan tool. See scan tool manufacturer's instructions and repair as necessary.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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