U029D 87 Fault in communication with Nox sensor

[Autoholm]

Hello

C4 blue hdi 1,6 2016 Win: :
VF7**************[VIN obfuscated, can be read by forum staff]
Første reg:
06-01-2016
Motorkode:
BH02

I would be very happy if someone could help me.

I did change the Nox sensor and repair with diagbox9.125 but still get the same U029D.
There is current in the wire/connection 12 volt and 2,5 volt.

Any idea?

Thanks in advance
peter

[GiveMeABreak]

On some vehicles this fault without the 87 at the end is referred to in a technical bulletin and required updating of the engine management software, so I can't say for sure if this would be the same with the '87' on the end, but here is the full fault code info:

Fault Code:	U029D 87
Description of Fault:	Emissions control CAN network (Downstream NOx sensor) : Missing information. Fault in communication with the NOx sensor: Information absent.
Conditions for Fault to clear:	At least one of the following conditions must be fulfilled - After switching the ignition off and then back on - Driving for 5 minutes
Downgrade Modes whilst Fault is active:	Activation of the cruise control or speed limiter function impossible Deactivation/cut-off of the cruise control or speed limiter Switching on of the urea solution warning lamp, then message, then inhibiting of restarting of the engine. The following warnings: "Stop and Start" warning lamp, Warning message, Engine diagnosis warning lamp
Symptoms:	-
Suspect Areas:	Fuse Passenger compartment fuse box Downstream NOx sensor Electrical harness Urea pump - gauge module Connectors Engine ECU DeNOx system relay Supplies protection and management unit

[Autoholm]

Thank you very much. I will try updating, and tell you how it goes.

[GiveMeABreak]

Be aware that this can only be updated from Citroen's Servers, so you will need an account with paid access or will need to get the dealer to apply it (if it is relevant to your vehicle). Best of luck.