View Full Version : Lamba O2 Sensor Fault

04-06-2017, 10:55 PM
Hopefully my experiences with my lambda sensor will help someone else out there.
At 71755 miles my A4 Avant S-Line 2.0 TDI 177PS came up with the following error code after putting up the engine warning light on.

01: Engine (J623-CGLC)
1 Fault Found:
5120 - Oxygen (Lambda) Sensor B1 S1
P2196 00 [237] - Signal too High (Rich)
MIL ON - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 7
Mileage: 115140 km
Date: 2017.03.16
Time: 15:10:41

Engine speed: 1517.50 /min
Normed load value: 0.0 %
Vehicle speed: 84 km/h
Coolant temperature: 90 C
Intake air temperature: 13 C
Ambient air pressure: 970 mbar
Voltage terminal 30: 14.820 V
Unlearning counter according OBD: 40
Air mass: actual value (mg/stroke): 574.9 mg/stroke
Mean injection quantity: 0.00 mg/stroke
O2 sensor 1 bank 1: adjusted oxygen value: 0.06112
O2 sensor 1: bank 1: voltage raw value O2 signal: 843.4 mV
O2 sensor 1 bank 1: voltage reading Ri-signal: filtered.: 1001.6 mV
O2 sensor 1 bank 1: duty cycle O2 heater: 45.74 %
Particle filter: difference pressure: 29 hPa

As I have Ross-Tech cable I cleared the fault and waited while investigating on the internet.

Apparently there are several things that can give this error as well as a faulty sensor, mostly air leaks making the system think it's running rich.
The main thing I was watching the MPG which stayed the same throughout the time before I changed it. As the MPG was steady as a rock it pointed to the sensor being faulty and not over fueling.
The problem returned after about every 200 miles several times, each time I cleared it and carried on monitoring.
A genuine Audi replacement is 178, wow. I opted for a Bosch one at 68 and 14 for a Lambda socket from Halfords.

Within 30 mins of starting I had a new sensor fitted and working. The only thing that I can see between the Audi and Bosch sensors is the Bosch has a longer lead on it. So basically you pay an extra 110 for a shorter cable that fits exactly, instead of having to cable tie it up out of the way.

I hope this helps someone

Happy driving

01-07-2017, 09:10 PM
I have a similar problem on an 07 A3 2.0TDI 170 that I've just bought. It's not showing exactly the same codes as yours but along similar lines. Do you think replacing the sensor would also fix this?
1 Fault Found:
009766 - Linear Oxygen (Lambda) Sensor B1 S1 Pump Current Trim Circuit
P2626 - 008 - Open - Intermittent - MIL ON
Freeze Frame:
Fault Status: 10101000
Fault Priority: 2
Fault Frequency: 4
Reset counter: 40
Mileage: 232086 km
Time Indication: 0
Date: 2017.07.01
Time: 13:24:30

Freeze Frame:
RPM: 1312 /min
Torque: 0.0 Nm
Text: 31.88
Text: -0.04 V
Voltage: 4.20 V
Text: 784 C
(no units): 108.0

01-07-2017, 11:25 PM
I'm afraid I can't give you an answer with any certainty.
The way I read it though the pump circuit is part of O2 sensor itself.
But looking at it 70 for a potential 'cheap' fix compared to paying Audi service prices for them to tell you the same error code and then 170 plus labour for the job,I'd give it a go.



08-07-2017, 12:39 PM
Thanks for the reply. I've just fitted a new sensor this morning and the same fault has come up without even starting the engine. I've cleared the codes and it immediately comes back up.:aargh4: