Diesel engines are reliable, economical & long lasting, as generator, car, marine & truck users know.
However, they emit NOX (Oxides of Nitrogen), causing urban smog & poor air quality, affecting breathing.
Injecting Urea - Ad blue / DEF - before the exhaust slip catalyst significantly cuts NOx emissions when controlled by 2 NOx sensors located pre injection & post catalyst.
Pre injector sensor 1 measures pre Ad blue / DEF emissions, controlling Ad blue / DEF injection, then checked by post catalyst sensor 2.
Typically, sensor 2 will see a 90% NOx reduction to sensor 1 from 400ppm to 40ppm.
However NOx sensors cannot distinguish between NOx & Ammonia, created when Ad blue / DEF is injected to a hot exhaust - So, when you see a SCR performance fault warning light, it’s easy to misdiagnose what’s wrong, wasting time & causing expensive repairs - Typical problems are a faulty SCR or Ad blue / DEF injector or NOx sensor or slip catalyst but which, how to know & how much to fix?
You need 2 tools to understand what’s going on - your scanner & a handheld NOx tailpipe exhaust analyser like our KANE-EGA1NO - here’s how:
Use your scan tool to check sensor & Ad blue / DEF status.
Now use your handheld analyser to take a NOx tailpipe test.
This table shows what your scanner & NOX analyser are seeing and what to do next.
To explain further:
If scan tool sees sensor 1 measuring 400ppm & sensor 2 800ppm BUT your NOx analyser sees 400ppm, SCR or Slip Catalyst is probably faulty.
If sensor 1 sees 150ppm, sensor 2 sees 300ppm & NOx analyser sees 300ppm, sensor 1 is probably faulty.
If sensor 1 sees 600ppm, sensor 2 sees 400ppm BUT NOx analyser sees 10ppm, sensor 2 is probably faulty.
If sensor 1 sees 400ppm, sensor 2 sees 400ppm BUT NOx analyser sees 400ppm, Ad blue / DEJ injector is probably faulty.
If sensor 1 see 400ppm, sensor 2 sees 400ppm BUT NOx analyser measures 250ppm, SCR is probably faulty.
Quick, easy & right first time.
AD blue / DEF injection systems reduce NOx emissions but you can misdiagnose a fault, even with a scanner - You need to simultaneously use your scanner with our KANE-EGA1NO NOx tailpipe emissions tester to see what’s wrong, fix right 1st time, saving everyone time & money.
NOTE: Use your analyser long probe to check “engine out” NOx emissions before SCR system - High NOx emissions stop SCR functioning and indicate a possible engine issue.