16514 - Oxygen (Lambda) Sensor B1 S1 fault code

[Crasher]

OK, I want you to do a resistance measurement on the lambda heater. It is the two white wires at the plug.

[smithy602179]

what should i expect on resistance . and do i need ignition on/off ? plug connected ? hot/cold engine . as you can probably guesss i not done this before lol

[Crasher]

I can't remember the figure, I will have to look it up but it is plug disconnected, engine cold and not running.

[smithy602179]

cheers crasher will check it now . brb hope you had a good xmas

just been out to car (thought better half had it ) done the resistance test on the 200 setting and got the result of 6.5

[martin1810]

Lambda heater resistance should be between 1 - 10 ohms roughly, with the engine cold. If you have VCDS lite, can you not look at lambda values in measuring blocks. Sounds like you have a wiring fault. This should show up with vcds. I don't have lite, so I am not sure what it can show.

[smithy602179]

oh where to start looking for the wiring fault .prob under ecu????

[pvcprinting]

Hi folks,Sorry to jump in on this thread, but also having the same trouble with my 2004 A4 1.8T CabrioletWas going to do the resistence check as outlined here but when i took a look at the plug i note that i dont have 2 white wiresI am assuming the plug you refer to is the plug that comes from the front lambda sensor and goes into a plug that sits underneath the coolant expansion tank?Mine is a 5 wire typeWhiteGreyBlackBlueRedwires present

[Crasher]

The heater (Z19) resistance wires are always white on the sensor side of the plug and red/white (- from the ECU) at pin 4 and green/yellow at pin 3 (+, from fuse 34 in the dash side fuse board) on the car side of the plug for an A4 2004 with an AMB engine so if you unplug the sensor at the connector you mention, measure the resistance across pins 3 and 4 down to the sensor.

[pvcprinting]

The heater (Z19) resistance wires are always white on the sensor side of the plug and red/white (- from the ECU) at pin 4 and green/yellow at pin 3 (+, from fuse 34 in the dash side fuse board) on the car side of the plug for an A4 2004 with an AMB engine so if you unplug the sensor at the connector you mention, measure the resistance across pins 3 and 4 down to the sensor.

Measured across pins 3 & 4 with engine cold and got a reading of 3.5 OhmsMeasured for Voltage from pin 4 to ground and got a reading of 0 (zero) Volts when engine turned over

[Crasher]

red/white (- from the ECU) at pin 4 and green/yellow at pin 3 (+, from fuse 34 in the dash side fuse board)

Pin 4 is the modulated earth and pin 3 is the fuel pump running power supply.