mbfan03

Hey guys I took my car into mercedes service 3 times for a cel and these codes came up. they first told me it was my o2 sensors so i changed them and the light came on again after 50 miles i took it back and they told me it was my o2 sensors and i told them they changed them already so bench tested them and they said they were ok, and then they blaimed the wiring was bad for the air pump and also the air pump was dead, i went ahead and changed the air pump my self, these codes still pop up. what should i do? i need to get rid of this cel i feel like mercedes is missing something or the techs are dumb.

P0140 O2 Sensor Circuit No Activity Detected (Bank 1 Sensor 2)
P0141 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)
P0160 O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 2)
P0161 O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

this is a new one
P0105 Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction

john89011

I think when you replace the air pump you need to replace the relay to the pump sice the relay shorted your pump. Disconnect your current pump because it will short that one out too. Go to the dealer, there was a recall on the relay to the pump. They should be able to replace it for you at no charge. This is the secondary air pump you're talking about right?

mbfan03

thanks for the replay i had the recall done already and after that everything went down hill i feel. yes the air pump on the passengers side in the front on top

Zeppelin

Is your car under warranty? Take it back to the dealer. If not, then looks like 02 sensor failure or wiring. What sensor did the dealer replace?

mbfan03

The Car Is Under The Mercury Waranty The Dealer Changed The 2 After Cat And One Before Cat.