Quote:
Originally Posted by rondeo
"The DP reading fluctuates wildly"
Sensor or sensor wiring faulty?
"Is 700 km further than usual between regens"
Depends on driving conditions. 300 + I'd say.
"How does the ECU decide when to regen, and how long to keep it going?"
I guess it is based on DPF_SOOT and DPF_LOAD.
DPF_SOOT is a calculated value based on various engine operating parameters.
DPF_LOAD is inferred from the differential pressure measured across the filter.
I guess the time taken will depend on how long it takes for filter temp to reach 600 degrees and on the measured differential pressure.
Check the hoses and the sensor. To check the sensor I guess you'd use a DVM and a hand operated vacuum pump. Or get another from a wrecker which is what I did to carry as a spare.
You also play around with it and learn how to test it.
I'd say the wiring is more likely to give an intermittent fault though, not sure. |
Thank you. "wildly" may have been overstating it. I am using the Dashboard display in Forscan Lite, and because the increments are quite wide, the needle on the gauge really jumps around sometimes.
DPF_SOOT and DPF_LOAD are not showing in Forscan, so the only PID relating to the DPF is DP. I would really like to see what SOOT is doing to have some understanding of why the CEL is coming on. I might try using Forscan on the laptop to see if more PID's show up.
At first I thought it was the hoses, as the first info I saw in Forscan was a few km after a regen and showed low DP readings. But it appears that the DP sensor is working because the readings increased, and then went back to zero after the regen.
Time to have a look under the car. At least it is running well and the fuel consumption is normal, so it appears whatever is causing the CEL to come on is not serious.