DIAGNOSTIC MANUAL

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Diagnostic Manual

FREQUENTLY ASKEDQUESTIONS (FAQ’S)

11) Question: What is OBD, and what are its benefits?

Answer:

OBD stands for "Onboard diagnostics," a computer based system built into modern vehi-

cles. OBDmonitors the performance of some of the engines' major components, including individual

emission controls. The system provides owners with an early warning of malfunctions by glowing

"Malfunction Indicator lamp" or ‘MIL’ on instrument cluster. By giving vehicle owners this early warning,

OBD protects not only the environment but also consumers, identifying minor problems before they

become major repair bills.

12) Question: How does one know the OBD system is working correctly?

Answer:

When the ignition is turned ‘ON’, the "MIL" lamp should ‘ON’ for few seconds, indicating

that the OBD system is ready to scan your vehicle for any malfunctions. After cranking the engine, if

the lamp should goes ‘OFF’ means the OBD system is working properly. But in case of Lamp remain

continuously ‘ON’ means there is emission related faults present in the electronic control unit memory.

The functioning of MIL lamp may also be checked by the traffic police using generic scan tools or

specific devices.

Caution:

Customer is advised to take his vehicle to a TATAAuthorized service center immediately for

diagnosis & repair. Delaying assistance could lead to more expensive damage.

13) Question: What does it mean if the light turns on while I'm driving?

Answer:

If the lamp comes ‘ON’ and stays, the OBD system has detected a problem. The vehicle

might have a condition that wastes fuel, shortens engine life, or causes excessive air pollution. If left

unaddressed, these conditions could also damage the vehicle and lead to increasingly expensive

repairs. For example, OBD can identify engine misfire (which can lead to severe or permanent en-

gine damage).

14) Question: What should be done if the light stays on?

Answer:

There is no cause for panic. The vehicle is just telling to seek attention soon. If the ‘MIL’ lamp

is continuously ON after cranking the engine, there is emission related faults present in the electronic

control unit memory. The functioning of MIL lamp may also be checked by the traffic police using

specific devices.

Caution:

Customer is advised to take his vehicle to a TATAAuthorized service center immediately

for diagnosis & repair. Delaying assistance could lead to more expensive damage.

15) What does it mean if the light is blinking?

Answer:

If the light is blinking, a severe engine problem such as a catalyst damaging misfire is

occurring & should be addressed as soon as possible. You can still drive safely, but should minimize

your time on the road. Try not to drive the vehicle at high speed or with excess weight (such as towing

or carrying heavy equipment).

16) What will the technician do in the work shop?

Answer:

A dealership should have a laptop based TML diagnostic tool or OBD II compliant generic

scan tool (a small, handheld scanning device) to diagnose the cause of the vehicle's problem. The

qualified technician will have the proper tools and know how to diagnose your vehicle.

The technician will connect the scan tool to the vehicle's OBD connector under the dashboard through

OBD cable & vehicle communication interface. The technician will check for DTC present in the elec-

tronic control unit & repair the vehicle based on manufacturer recommendations. OBD actually helps