TheProud Angel

Hi,

I dont know what to do anymore! I need a smog check and I already changed the two O2 sensors on my CLK350 2006. I drove cycles and cycles to get the monitors ready. all of the sudden the P0140 and the P0160 came back on my OBD. I deleted the codes and drove again, thought might just a hick up ... nope ... still coming back on. I dont know where to look anymore. Has someone an idea?

P0160 O2 sensor circuit no activity detected 2 bank sensor 2
P0140 O2 sensor circuit no activity detected Bank 1 sensor 1

Also my OBD is showing me Catalyst Mon = Inc.
Sec. Air system = Inc

I don#t know what to do anymore! someone has an idea?

Thanks in advance!

Bankroll

The odds of both sensors being bad at the same time is a red flag that it is something other than the sensors., Unless you bought some Ebay fakes. Damaged/melted wiring, or leaking exhaust. Make sure the O2 heater fuse is OK. Damaged ECU. Need to have it properly diagnosed with scan data.

TheProud Angel

Thank you for your post.. mmhhh will check the wires ..
Fuse and relay are good. Tested. I bought them on amazon if I’m honest. I will try to clean the old once. Does someone has experience with cleaning the O2 sensors?

Rudeney

Amazon is full of fake parts. I avoid them and ebay for anything "critical".

TheProud Angel

I know but I’m about to sell the car so I don’t want to spend so much money on parts. I cleaned the old o2 sensors maybe that will help. Any experience with cleaning them and plug them back in?

TheProud Angel

ok I sent them back. bought bosch the same I had before. deleted the codes and know they showing up again.. P0140 and P0160. do I have to drive the cycles first to get rid of them?? do you know that?

Thank you.

Rudeney

Actually, those codes indicate that the sensors are unplugged. have you checked the wiring?

TheProud Angel

mmhh there is this plugin connection so there isn’t anything what can go wrong plug in and that’s it or what wiring do you mean? I’ll double check the connection plugin‘s

Rudeney

The harness that the O2 sensors lug into end up at the ECU. Along the way, they run precariously close to the exhaust pipes and manifold. If a clip breaks, they can contact the hot pipes and melt.