NOx Sensor Testing

A quick video showing how to check the NOx Sensor circuit to determine whether the issue is in the loom or the sensor. The test was carried out on a Renault Midlum but can be adopted for other manufacturers.
Light vehicle Technicians can do the same test. Just expect 12V as a supply voltage not 24V.

[@doriancharles608]

Thanks!!!!!! keep them coming finally some who works on European trucks who presents in english great job man

[@trucktechtips638]

Many thanks, definitely more to follow.

[@paulw2791]

Finally, someone else using a picoscope on a truck! I work on Cummins in the States and just got a 2204a. Thanks for the video and keep them coming please! If you know any others on youtube making videos with a picoscope on a truck please share!

[@trucktechtips638]

Many thanks for the comment Paul. There will be plenty more Pico videos to follow.

[@trevorfarren2186]

Fantastic outline of the procedure, definitely going to subscribe

[@trucktechtips638]

Many thanks. Should be creating more videos soon.

[@thelazystrummer]

Perfect diagnostic methods. Will be subscribing 😁

[@trucktechtips638]

Thank you 😊

[@affieuk]

Clearly explained, thanks for this. I'll be testing those points on my sensor.

[@trucktechtips638]

Thank you.

[@ianaristotlethompson4186]

Very informative. Thanks.

[@trucktechtips638]

You're very welcome.

[@John-zh2zy]

Thank you the video is super helpfull and in good detail

[@trucktechtips638]

You're welcome! Thank you.

[@advancedleveldiagnostics]

Great job, Thanks for sharing! Is there a way to test the actual sensor, not just the module?

[@trucktechtips638]

Hi, there are a number of NOx/O2 sensor tester kits available in the market. My friend has one. I will find out the make and model and let you know.

[@vladmoloce8915]

Do you have a video for 5 pins as well? My nox sensor 2 has 5 pins. Yours in video is with 4 pins. I changed the nox sensor and now is failed again. P229 FO9 NOx sensor 2 (cylinder bank 1) has a malfunction. There is a component fault. --NOx sensor 2 (cylinder bank 1) has a malfunction. No signal change: Voltage level is too low.--The switchover between the maximum and minimum values of NOx sensor 2 (cylinder bank 1) is too slow. There is a signal below the permissible limit value. .. i changed one nox sensor and i suspect to by problem with wiring and not nox sensor. Thanks

[@trucktechtips638]

Hi there, what vehicle is it fitted to? Some 5 wire NOx sensors do no use the 5th wire. So they only have a positive, negative, CAN Hi and CAN Lo. Sometimes you can get downstream NOx sensor issues if the SCR catalyst is not performing as it should.

[@abdalgadermohamed5636]

beautiful

[@trucktechtips638]

Thank you! 😊

[@mattiel9156]

Would you recommend getting a 2 or 4 channel picoscope? thank you !

[@trucktechtips638]

Hi, I would always recommend going for more channels if possible. This means you can measure power/ground and signal at the same time when you are looking at most sensors. Really depends on your budget. I have both, I started with the two channel which cost me £150 ($195). Relatively cheap, but got me used to using the software.

[@DavyDiag]

Can please give a little info on the scan tool you used? ie: make Ancel...model?

[@trucktechtips638]

Hi Neil. It's an Ancel X6 HD, they retail about £450.00 ($545.00). You get what you pay for with scantools. We haven't had any success with it on Iveco. DAF, engine and SCR faults but no ABS. Volvo, Renault, Dennis pretty good to be fair. The tool allows for 1708 CAN diagnosis which is helpful on these models.

[@DavyDiag]

@@trucktechtips638 Thankyou

[@nikolajovanovic3676]

Is it the same procedure on the Iveco Stralis 450 E5 2007? The problem is that after replacing the sensor, it reports an error: LONG TERM NOX SENSOR FAILURE DTC:45F. By replacing the sensor (from another manufacturer), it reports an error :NOX SENSOR FAILURE DTC:1A3! Three new sensors have been changed and all three are showing errors. I ask for help and advice. Thank you!

[@trucktechtips638]

Hi there. So there are a few things to consider. Firstly you need to make sure that the NOx sensor that you have fitted is the exact component for your vehicle. Different manufacturers may have CAN High and Low swapped round. Secondly are there any other DTCs stored? Do you have any for EGR for example. The EGR also assists with the reduction of NOx. If there is an issue with this system NOx levels will be higher than normal. Thirdly, does you vehicle have a pre and post NOx sensor or just a post NOx sensor. Potentially the SCR catalyst could be an issue although this is only in extreme cases. Just a few things to consider.

[@nikolajovanovic3676]

Thanks for the reply, problem solved. The problem was in the SCR catalyst. Thank you!

[@merlindxb4333]

Hi as an aside is there a way of using the NOx sensor to detect Nitric Oxide at parts per million as a stand alone test set, the real one cost $885. I have a iNO generator on my workbench bench and want a test sensor

[@trucktechtips638]

What an interesting question. I scraped a pass at Chemistry at school so take my answer as one not coming from an expert. In theory, yes, your commercial NOx sensor can measure in the region of 0-1600ppm. The term NOx that is used is only the collective term for Nitrogen Monoxide (Nitric Oxide) and Nitrogen Dioxide I believe. The iNO generator you have is this a respiratory machine? Have a look at this article I found about NOx sensors. There is a fair bit of reading in it but it discusses what the sensor is actually doing. dieselnet.com/tech/sensors_nox.php#:~:text=The%20NOx%20measurement%20range%20is,%C2%B110%20ppm%20%5B3899%5D%20.

[@VIP-ry6vv]

This is the difference between a real mechanic and someone who just replaces parts. Anyone can replace a part.

[@AndyRRR0791]

Interesting measurements but I bet if you disconnected the NOx module while the truck was running you'd get a DTC that was shouting that something was wrong with the comms to that unit so most of these measurements could be short-circuited, so to speak.

[@trucktechtips638]

True, but what if it wasn't on the CAN. I had a NOx fault where the issue was a voltage drop on the earth. Loading the circuit at the sensor proved it. Comms issues are not always relating to comms wires.

[@nickayivor8432]

👍

[@sintopaul9980]

Can you explain about 6 wire socket nox sensor Man truck

[@trucktechtips638]

Hello there. I haven't specifically seen the MAN 6 wire sensor, but I have seen 5 wire sensors which contain 2 earths, 1 positive and CAN High and CAN Lo. I will have a look out for one and do a video on it. Thanks for the question.