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 Diagnostics: Notes
A scan tool is used to retrieve and clear DTCs. Scan tool also has several features that can be used to help locate an intermittent condition. When scan tool is used for system tests, it will display values actually seen or commanded by various systems (i.e., BCM, PCM, instrument cluster, EBCM or SDM). This will usually include following types of information:
- Analog Data Input
Displays analog input seen by system. - Inputs/Outputs
Displays digital values as seen by system, and provides indication of whether input or output has cycled. - Special Functions (Output Controls)
Allows for outputs of system to be set at a desired value (ON or OFF). - Clear Codes
Will erase DTCs for system currently selected (if problem still exists in system, DTC may immediately reset).
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.