Faulty code P0234

[KennyW]

Hi All,


The above fault code came up after a check with Diagbox.

Clicking on code the following was listed:


Charge pressure regulation
Permanent Fault
Air pressure lower than the settings

along with the following data

Engine speed 2912 RPM
Coolant temp 78 c
Speed 133 KPH or 70 mph
Turbo Pressure reference value 2.53 Bar
Turbo Pressure 2.97 Bar


This occurred during acceleration and changing from 5th to 6th gear.

Cleared fault and has not returned since.

Possible cause small hole in a hose in turbo and related piping.

No obvious change in vehicle performance.

Kenny

[Paul-R]

Is this the X7?

[GiveMeABreak]

P0234 - Delphi ECU

Boost pressure regulation: Air pressure above the reference value

Engine speed between 2000 and 3000 rpm - Engine torque below 300 N.m
The measured turbocharged air pressure is 450 mbar above the reference value (For 6 seconds).

Code activated when the following conditions are in force:
- Engine speed above 1500 rpm
- The actual engine torque is higher than 100 Nm

Fault disappearance Conditions: Driving with engine hot for 5 minutes, with several accelerations at full load for 10 s followed by foot-offs.

Back up Modes in effect whilst the fault is active:

• Deactivation of the request for regeneration of the particle filter from the diagnostic tool
• Deactivation of the EGR function
• Cutting of the exhaust heat saver function
• Prohibition of regenerations of the particle emission filter and stopping of those in progress
• Deactivation of the kick-down for automatic gearboxes
• Limitation of performance
• Request for emergency closing of the turbocharged air cooler by-pass
• Deactivation of the tight spot for the cruise control

The engine management lamp may be lit along with the 'service' lamp.

Possible Symptoms:

• Noise
• Diesel fuel consumption a bit higher
• Lack of power
• Engine hesitating, cutting out
• Smoke from the exhaust

Suspect Areas:

• Supercharging pressure sensor (Sensor drift ; Connectors ; Electrical harness)
• Manifold air entry pressure sensor
• Turbo air cooler by-pass unit
• Electrovalve of the turbo air cooler by-pass unit
• Position indicator of the turbocharging air cooler bypass unit
• Turbocharger
• Turbocharger electrovalve
• Position indicator of the turbocharger

[KennyW]

Thanks Marc,

Yes, it is the X7 Paul

As usual a list of possible fault areas but nothing specific.

Where do you start ?

In the list of symptoms, I have not noticed any of them mentioned.

Kenny

[GiveMeABreak]

That's the trouble - any one of these can cause the same symptoms - so a matter of either ignoring it and letting the fault develop (if it ever does - may just be temporary) and see if it then triggers any other codes. Easy enough to clear following the guidance though - 10 full load applications , and foot-offs after the engine is up to temp.

[KennyW]

Thanks Marc,

No returned yet.

Kenny