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Diagnostic Manual
technicians to do their job more quickly and reliably, helping you avoid unnecessary repeat customer
visits to the workshop.
17) Can the OBD system be repaired, deactivated, or modified?
Answer:
Any alteration or changes in vehicle configuration that changes the vehicle from a certified
configuration to a non-certified configuration is considered tampering which may affects the threshold
emission levels of vehicle also. This applies to both vehicle owners and repair facilities and is, there-
fore, an offense. Replacing a catalyst with a straight pipe is one traditional example of tampering.
Likewise, overriding the OBD system through the use of high tech defeat devices or non-certified
computer chips, for example, would also be considered tampering.
18) What should one do if the light goes out before taking the vehicle to the shop?
Answer:
Usually nothing, if the problem that caused the lamp to come ‘ON’ is addressed, the OBD
monitor will turn the lamp ‘OFF’. This is not an indication of a faulty OBD system. In fact, the system is
doing its job by verifying that a problem temporarily existed but has since been corrected. The vehicle
needs no special attention unless the light comes on again.
19) What else one can do to make sure the vehicle is running well and to minimize its
environmental impact?
Answer: Today's vehicles are highly sophisticated and efficient. OBD helps to ensure these vehicles
are running well under emission limits, but you still need to maintain your vehicle according to the
manufacturer's recommended schedule of routine maintenance and keep an eye out for your ‘MIL’
lamp. Always turn off the engine before refueling and always make sure the gas cap is securely tight-
ened. You'll save money on fuel and repairs while helping to do your part to protect the environment.
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FREQUENTLY ASKEDQUESTIONS (FAQ’S)