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.
2004 Chevrolet Optra (CANADA) L4-2.0LFACTORY OEM SERVICE PROCEDURE
Scan Tool Does Not Power Up
Scan Tool Does Not Power Up
Circuit Description
The data link connector (DLC) provides operating power for the scan tool at terminal 16. The ground for the scan tool is provided at terminal 4. The 16 pin DLC provides the serial data signals at terminal 7 - ECM, TCM, terminal 3 - speed sensitive power steering, terminal 12 - EBCM, and terminal 13 - SIR serial data. The scan tool will power up with the ignition OFF. The ignition must be ON in order for the scan tool to communicate with a control module.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
1. Fuse F16 supplies power to terminal 16 of the DLC.
4. The battery positive voltage and ground circuits of the DLC are functioning properly. The malfunction must be due to the scan tool.
Factory Service Tools
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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.