DeNOX & Urea ad blue issues - 308 1.6 D

[finbarr1102]

VF3**************[VIN obfuscated, can be read by forum staff]

Hi, My daughter (informed me after the fact) that she hit something on the road which scraped under the car and then the engine light came on. I did look under the car and could not see any obvious damage so may have been a coincidence. I used Diagbox to find code which pointed to NOX sensor but was intermittent so when I cleared it it went but came back on occasion. Recently the urea light came on so I put some fluid in (not full) to get the light out which worked fine. Some weeks later the urea light came on again but this time I filled it up with fluid. I reset urea on the onboard computer and expected the light to go out after a while but it did not. I went to Diagbox and reset all errors thinking this would resolve problem but it did not. After a bit of driving I have just checked with Diagbox and got the following codes.

U029D 87
P2200 87
P20F6 00
P20E8 00
U0074 88

The urea tank pressure in the detail of the P20F6 code shows the urea tank pressure to be 5.44 so not sure the tank is an issue. Another factor to consider is the car had not been used for a year before I bought is so I am now wondering if the urea could have crystalized a bit during this time.

Regards, Finbarr

[PaulC5]

I do not know what the definitions of these codes are, maybe you could post them to help us provide help.

Have you checked if the NOx sensor on the exhaust is ok and its wiring is ok since it may have been damaged when the underneath was scraped ?

Many of us put Wynns crystal clean in the adblue tank when filling it to help avoid crystals forming.