2016 Ecodiesel 100% Full DPF P0428 Cat Temp Sensor RESOLVED

[krhd1113]

Hi all,
I recently got 100% full dpf see dealer warning. I connected my AlfaOBD to force a regen but it would shut down after about 5 minutes due to a cat temp circuit high P0428
the graph showed the cat temp steady around 630c then a straight shot up to 999.9c and shed idle down and quit the regen

instead of running out to replace the sensor at $200 cdn a friend advised to clean the egt in the manifold as this soots up and can mess up the cat temp sensor reading.
so I pulled off the passenger side plastic wheel well liner and I was staring right at it. You can see in the attached image the sensor above the dpf going into the manifold.
I soaked this with wd40 and got it quite easily (and I'm at 258,000km) I put a red solo cup with diesel and soaked it for at 30 minutes, wiped it off, hit it with the air nozzle and re-installed.
for good measure I put a high speed fan underneath my truck to cool the dpf - my thinking was I might keep it just a few degrees below that point of no return temperature that failed the temp sensor.... crazily enough this worked at holding down the temperature about 20 degrees and it slowed the climb up to 630 degrees significantly

anyway, I forced the regen and this time in completed! within 20 minutes my dpf was down to 10% soot load and all codes cleared.
The best part is this cost me NOTHING! $0.00 !!

obviously I am going to keep an eye on this now but for today my truck is back on the road and my wallet is no less empty as it was before this happened.
I hope this can help others who have had a similar issue

 

[nickdieselz]

The Exhaust Gas Temperature (EGT) sensors can indeed get fouled up with soot over time, especially with high mileage like your 258,000 km, which can result in incorrect readings like the 999.9°C spike you saw. Cleaning the sensor as you did is a good, cost-effective solution that can often prevent the need for a costly replacement if the sensor itself isn’t actually defective.

Your method of using a fan to control the temperature during the forced regen was also creative and shows that sometimes a practical workaround can save the day. Now that the DPF is down to 10% soot load and the codes are clear, it sounds like your truck is back in good shape.

Just be sure to keep an eye on those temperatures and sensor readings in case the issue resurfaces, and regularly monitor your soot load to avoid any further complications. This type of preventative care can go a long way in keeping the emissions system functioning without additional costs. Thanks for sharing, and this will surely help others who might face similar DPF or EGT issues!