2003 Volkswagen Golf 02 Sensor + Rattling Noise from engine

BILLYHUDSON94

MEMBER
2003 VOLKSWAGEN GOLF
1.6L
MANUAL

Hi,

I currently own a Volkswagen Golf 1.6 se match 03 plate, of recent the 'yellow warning/emissions light' has came on, the mechanic stated that the 02 sensor needs to be replaced. There is also a rattling noise when in idle and at low revs, when I accelerate more and get into higher revs the noise is no longer there. Is this a symptom of an o2 sensor of which needs to be replaced? Or could this be something completely different?

Many thanks for your time

1 Reply

CARADIODOC

MECHANIC
33,755 POSTS

This is impossible to tell over a computer, but the first thing to understand is diagnostic fault codes never say to replace parts or that they're bad. They only indicate the circuit or system that needs further diagnosis. Second, but possibly related, if the noise is related to an exhaust leak, between the pulses of exhaust gas flow, the momentum can draw in puffs of outside air, and that can lead to the O2 sensor detecting a false "lean" condition from the oxygen in that air.

The first thing is to have the fault codes read and recorded, then list the exact code number. There's dozens of codes related to oxygen sensors and they mean very different things. Some indicate an unacceptable condition, but that means the sensor is working properly.