C4 picasso bluehdi u029e 87 error code - has anyone had this? What was the solution please?

[Mexico14]

Error code u029e 87 when put on the diagbox. Cleared the code then it come back again.
Any idea what needs to be fixed?

Pressure of urea was reading at 0.5 bar it's usually 4.
Temperature of urea fluid was reading - 40. It's usually the ambient temperature.

[GiveMeABreak]

This fault can have several fixes depending on what has caused it. In some cases the CAN / Power / Earth wiring can cause loss of communication, requiring a new harness. In some cases a new tank is required and in other cases a software download to the engine ECU may be required. It depends on the vehicle, the system fitted and the results of the investigation / Diagnosis in connected mode.

This is the fault descriptor for your Engine:

Fault Code:	U029E 87
Description of Fault:	Fault in communication with the deNOx system: Absence of communication. Fault in communication with the deNOx system ECU. Possibility 1 Datastream absent Possibility 2 DeNOx system ECU absent Conditions of activation of the diagnostics: At least one of the following conditions must be fulfilled - Ignition on - Engine running The time of appearance of the fault code is 3 seconds
Conditions for Fault to clear:	Driving for 5 minutes
Downgrade Modes whilst Fault is active:	Lighting of the urea solution warning lamp, then message, then prohibition of restarting the engine. Engine diagnosis warning lamp
Symptoms:	-
Suspect Areas:	Engine ECU Urea pump - gauge module Electrical harness Connector Urea relay Fuse

[Mexico14]

Thanks Marc.

I put the car through an IMO car wash a couple of hours before the fault appeared - could that have caused it?

If a new tank is required, Is this is the fault that citroen have made a contribution towards the cost of fixing?

Where it mentions conditions for Fault to clear.. If I drive for 5 minutes that should clear the fault?

[GiveMeABreak]

Most certainly the water could of exacerbated the issue - if for example the wiring was wearing through and becoming exposed - any water like on one of those Carlos Fandango car washers that sprays water and bubble gum flavoured suds underneath and upwards of the vehicle causing a short.

As for Citroen contribution, your vehicle is coming up for 7 years old now, so unlikely. However, I'd allow the car to dry out and time for any water to work it's way out of any wiring - especially if it has got into the wiring sleeving. It may resolve itself, but a bit of a coincidence after the car wash to be honest, so may indeed by the cause. I'd avoid those things if possible as they will get water everywhere you don't want it.

Driving for 5 minutes may clear the fault, but I would leave the car to dry out for a while - it's certainly hot enough at present and see if that solves the issue.

[Mexico14]

This morning car wasn't wanting to go in to eco mode at first, although the mpg seems a fair bit improved over the usual average. Maybe a 15% increase. However the dreaded 700 mile countdown has reared its ugly head on my dash.
Should the empty /refill option in diagbox reset the countdown in this instance?

[GiveMeABreak]

Only if there isn't another problem....

[Mexico14]

When you say only if there isn't another problem... Is that limited to adblue related problems only?

With the temperature sensor reading minus 40. I guess the system thinks the adblue is frozen and thus won't try and pump it. Doesn't the tank have a heater?

Is the temperature sensor available as a standalone part?

[GiveMeABreak]

Adblue tanks have a heating system to prevent crystalisation if the temperature drops. There are heating elements in both the tank and along the supply to the injector near the catalytic converter.

If you harness is damaged then there may be no power to the tank, which will affect the heater too. I'd recommend you get it to your dealer and let them determine where the issue is.

[Mexico14]

Performed a pressurisation and effectiveness tests of the denox system. Doesn't look good.

[GiveMeABreak]

Ok, so in the case above, you most likely have a UREA injector problem.

The Adblue injector is at the top / side of the catalytic Converter. Urea can crystalise, which is why the adblue tank has a heater and the harness to the injector is heated to help prevent this in colder weather. However the Urea can still crystalise at or near the injector over time. Often when the injector is dismantled, you can see white crystals that restrict the flow. See pictures below:

When this happens of course, the engine management system via the NOx sensor, notices that the level of NOx is not as it should be and will put a warning up.

When the injector or the supply to it becomes blocked it will likely also cause back pressure - so this could be the second issue as per your screen shots.

As it turns out, my sister's C5 Aircross has a similar problem - Adblue warnings and the countdown, despite topping up the Adblue. It was at the dealership this afternoon awaiting a new injector.

[Mexico14]

That's interesting Marc. This product problem would be independent from the urea tank issue in guessing? What sort of cost is it to get this fixed?

[GiveMeABreak]

Basically it's another Adblue 'issue' apart from the tank problems. The problems with the tanks themselves can be rusting / crystallising, pump failure, necessitating a new tank. Then there's the NOx sensors that can fail, then the harnesses and then the actual injector failing as I mentioned above due to the crystallisation issues.

The Urea injector for your car is about £200 from Citroen, plus fitting if this is found to be the cause.

[Mexico14]

Hopefully it's the Injector rather than the tank!
I've overlook another fault code U1318 86 which on closer inspection has the exact same "date" as the U029E 87 fault code! The date is given as 1038937 - do you have any idea what this translates to in the standard calendar?

I think this may help pinpoint the problem.

[GiveMeABreak]

Here's the code, but that date looks invalid to me....

Fault Code:	U1318 86
Description of Fault:	Communication fault with the built-in systems interface: Communication not valid. Communication fault with the built-in systems interface: Frame too short. Fault confirmation time less than 1 second. Conditions of activation of the diagnostics - At least one of the following conditions must be fulfilled: - Ignition on - Engine running
Conditions for Fault to clear:	Driving for 5 minutes.
Downgrade Modes whilst Fault is active:	Irreversible deactivation of the vehicle speed limiter Irreversible deactivation of the vehicle cruise control Request for immediate restarting of the internal combustion engine Inhibiting of starting of the forced particle emission filter regeneration by after sales Deactivation of the gear change indicator Deactivation of the "Stop and Start" function Request for restarting of the electromotor sub-assembly ECU Absence of automatic stopping of the internal combustion engine Inhibiting of the calculation of the charge status permitting authorisation of stopping (of the engine) for the "Stop and Start" function Invalid engine torque information for the electric handbrake function Inhibiting of the network voltage maintaining device voltage reference value Inhibiting of the ancillary drive belt diagnostics Request to prohibit activation of the starter Warning Lamps: "SERVICE" warning lamp "Stop and Start" warning lamp
Symptoms:	Engine hesitating, cutting out Lack of power Malfunction of the Stop and Start switch or its LED Grinding / Squealing / Grating Absence of automatic stopping of the internal combustion engine Deactivation of the speed limiter Deactivation of the cruise control Activation of the cruise control or speed limiter function impossible Starting problem
Suspect Areas:	Configuration of the built-in systems interface Configuration of the engine management ECU Engine management ECU downloading Downloading of the built-in systems interface Electrical harnesses

[Mexico14]

I've cleared the U1318 86 and it hasn't returned. Performed some additional tests.

Urea pipe heating test: failed
Urea reservoir heating test: failed
DeNOx system relay control test: no fault
Check the bleeding of the denox system: test interrupted pressurisation syntax error @+:syntax error: @+incorrect

Also tool some readings whilst engine running.