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.
Output Diagnostic Test Mode (Function 03): Notes
When the Output Diagnostic Test Mode (DTM) has been selected with the (VAG 1551) Scan Tool, all fuel injectors, the idle air control valve, the EVAP canister purge regulator valve, and the wastegate by-pass regulator valve can be checked audibly or by touch.
Injectors are activated five times for two milliseconds. Avoid background noise when audibly checking injectors. The clicking sound from the fuel injectors is very soft and of short duration.
The Output DTM will be interrupted if the engine is started or if a speed pulse is detected.
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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.