P0140 Oxygen sensor after the converter - no signal (bank 1, sensor 2)
P0140 means there is no signal from the oxygen sensor after the converter (bank 1, sensor 2) - it is "flat". The most common causes are an open circuit or a faulty sensor heater (often together with P0141). As long as there is no signal, the control unit cannot assess how the converter is working.
Does restoration help?
Most likely not the catalytic converter
Most likely not: the code points to the sensor or its circuit, not to the converter, and restoring the converter will not fix this fault. If P0420 or P0430 is present as well, we assess the converter only once the sensor and its circuit are in order.
A code shows where to look, but it is not a final diagnosis. We make the decision at the workshop after diagnostics and measurement.
Symptoms
- Check Engine light on; the car usually drives as before.
- As long as the sensor is not working properly, the control unit cannot correctly assess how the converter is working.
- The code soon comes back after clearing until the cause is fixed.
Most common causes
- A broken wire or damaged connector.
- A faulty sensor heater - a cold sensor gives no signal.
- A faulty sensor.
Order of checks
What to do
- 1
Read the codes and data
During the computer diagnostic we look at all the codes and the live sensor signal to find out whether the fault is in the sensor, its circuit or somewhere else.
- 2
Check the circuit
Wiring, connector, fuse and heater circuit - the fault may be there rather than in the sensor itself.
- 3
Then the sensor and the converter
If the circuit is in order, the sensor most likely needs replacing. We assess the converter separately - only if P0420 or P0430 is present as well.
FAQ
Questions about P0140
The sensor only starts working once it has warmed up. If the heater or its circuit is faulty, the sensor stays cold and gives no signal - so both codes appear.
Not because of this code. P0140 relates to the sensor and its circuit. We assess the converter only if P0420 appears after the repair.
P0140
Not sure what is wrong with your car?
Tick the symptoms or enter the fault code - in 30 seconds you get a first assessment of whether the part can be restored. If restoring is no longer worth it, we buy the old converter.
Request
Book a check or a job
Leave your contact details - we will get back to you, clarify the situation and agree on a time.
- Phone+371 29 007 007
- Phone+371 28 777 998
- WhatsApp+371 20 099 444
- Emailinfo@autokatalizatori.lv
- AddressJūrkalnes iela 62, A7 bokss, Rīga
