I have AWM engine and have two codes : 1. Sensor Heating: B1 S1: Open Circuit and 2. Sensor Heating; B1 S1: Performance too Low.

There are two o2 sensors. One with four pins(brown) and one with three(black). Which one is B1 S1?

Also, I have a multimeter, but not sure about which pins to check. Can you guys post a pin out diagram or tell me which two pins to check the resistance across?

 

you should have 4 o2 sensors, 2 before the cat and 2 after.
b1 s1 means; bank 1 sensor 1, meaning the very first sensor.

 

That would be true if he had a v6. AWM is a 1.8 motor. b1s1 is the o2 sensor mounted closest to the turbo. I will check my bentley tomorrow and see if there's a pinout for you.

 

Just trace the wiring from the first sensor to its connector on the firewall under the coolant overflow tank and replace it.

 

Never mind. I found it. Here it is for future reference:

On AWM engine, there are only two O2 Sensor (two per bank, pre and post cat, 4 cylinder engines only have one bank).

The pre-cat one (B1 S1) has a six pin connector which is black in color. There are two rows of 3 pins each. To check heating element resistance connect ohmmeter to the two middle pins in each row.

The post cat has four pins in single row and the connector is brown. Both of these connectors can be accessed by removing coolant reservoir.

 

my bad.

 

Does anyone know if that is the same for the AEB (1.8T) engine?
B1S1/front/upstream black, B1S2/rear/downstream brown?

 

According to ECS the AEB is reversed.