2000 C2
Over the past year my CEL has came on a few times and this is the fault code.
0154 02 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)

Car runs great so I have just erased the code each time - it seems to happen right after cold start up with cool ambient outside temp
My question is do I need to do anything? or just reset CEL and Keep driving it.

 

I think MkI has a TSB for o2 sensor wiring issue but I don't know the details. Do you have a scanner that can read O2 sensor voltage in real time? If you do, you can plot the pre-cat O2 sensors on both banks and compare their patterns. Then go wiggle the wire of the bank 2 pre-cat sensor and its connector and see if you have any signal drop out.

 

Once upon a time I cured an intermittent CEL -- related to a cam timing sensor in my '96 Mustang GT -- by disconnecting then connecting the sensor. I suspected there was some marginal corrosion at the connector that the simple act of disconnection and connection would remove.

Afterwards the CEL never came back. (The engine suffered from a number of oil leaks which required the engine be washed to remove the oil and one intake manifold failure which flooded the engine compartment with hot coolant that also required the engine be washed to remove the remains of the coolant. I believe all this washing exacerbated the development of corrosion at least at this one sensor connection.)

The #1 sensors and their connectors are rather exposed to the elements. This disconnect and reconnect only costs you the effort of getting under the car -- safely (I just back my cars upon on a set of Rhino Ramps) -- and letting the engine cool down before you go at the connector. Be sure you treat the connectors and sensor wring lead and harness connector and wring with care. They are old and you want to be sure you are gentle yet of course use sufficient force to effect the disconnect. Be sure too you properly reconnect the sensor. Might do both sides. The thinking is the other side might be nearly as bad and about the time you get the 1st side "fixed" the 2nd side will then trigger a CEL for the same reason.

 

Thanks for the advise gentleman - I will look at the wiring and connectors

 

Maybe use some deoxit too.

 

Actually it's not recommended to use any contact cleaner or similar products on the O2 sensor electrical contacts as it may damage the sensor. The sensor is actually connected (breathe) to the atmosphere air via the wire of the sensor.

https://books.google.com/books?id=nY...sensor&f=false

 

Wow. Good to know. I was just about to go through the engine and deoxit all the connectors I can reach.

Any others I should not clean?

 

The O2 sensor is a bit special.
No other sensors have this potential risks as far as cleaning the contacts is concerned.

 

Really none of the electrical connectors need "cleaning".

In some cases a disconnect and reconnect can cure a marginal contact problem as this removes some surface corrosion. The O2 sensors only operate (the narrow band ones at any rate) between 0 to 1V (max) so any corrosion at the connector can possibly affect the sensor reading.

 

Had my Indy test the sensor and it was bad - have replaced it with new OEM part $125 for sensor and $120 labor

 

Glad to hear it's that easy