Needing advice with several fault codes

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jmr10
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Needing advice with several fault codes

Post by jmr10 »

Hi,

I have a 2011 Citroen C3 that has a few fault codes;

U1401 - Alternator LIN network registering of a fault (on slave node of alternator LIN network)

P12B4 - Exhaust gas recirculation valve position incorrect - too closed (after-sales)

P0490 - Exhaust gas recirculation valve position incorrect - too closed

P0299 - Charge pressure regulation, air pressure below the setpoint

Just wondering if P0299 could be related to the EGR codes? And does anyone know things to check for code U1401?

Any help appreciated, thanks
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GiveMeABreak
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Re: Needing advice with several fault codes

Post by GiveMeABreak »

VIN please. Please post your VIN in full without spaces - it will be automatically masked from public view after submitting your post & will only be visible to staff.
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Re: Needing advice with several fault codes

Post by jmr10 »

VF7**************[VIN obfuscated, can be read by forum staff]
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Re: Needing advice with several fault codes

Post by GiveMeABreak »

These are the descriptors for the faults:
Fault Code: U1401
Description of Fault: Alternator LIN network: Registering of a fault on the slave node of the alternator LIN network. Faults in communication between ECUs on the LIN.
Conditions of activation of the diagnostics
:At least one of the following conditions must be fulfilled
- Ignition switched on
- Engine running
Conditions for Fault to clear:
  • Driving for 5 minutes
Downgrade Modes whilst Fault is active: -
Symptoms:
  • Jerking/stalling
  • Starting problem
  • Lack of power
Suspect Areas:
  • Engine ECU
  • Alternator
  • LIN network

Fault Code: P12B4
Description of Fault: EGR valve: Position incorrect (too closed) (Service). The position measured is greater than the reference by more than 15 % for 5 seconds.
Conditions of activation of the diagnostics
-Engine speed between 700 and 3500 rpm
Conditions for Fault to clear:
  • Driving for 5 minutes remaining under an engine speed of 3500 rpm at half load
Downgrade Modes whilst Fault is active: -
Symptoms:
  • Jerking/stalling
  • Smoke from the exhaust
  • Lack of power
  • Noise
  • Slightly higher fuel consumption
Suspect Areas:
  • EGR valve
  • Particle filter overloaded
  • Electrical harness
  • Connectors

Fault Code: P0490
Description of Fault: EGR valve: Position incorrect (too closed). The position measured is greater than the reference by more than 20 % for 5 seconds'
Conditions of activation of the diagnostics
-Engine speed between 700 and 3500 rpm
Conditions for Fault to clear:
  • Driving for 5 minutes remaining under an engine speed of 3500 rpm at half load
Downgrade Modes whilst Fault is active:
  • Reversible deactivation of the vehicle speed limiter
  • Reversible deactivation of the vehicle cruise control
  • Switching on of the warning lamp and/or warning message: Warning lamp MIL
Symptoms:
  • Smoke from the exhaust
  • Noise
  • Jerking/stalling
  • Lack of power
  • Slightly higher fuel consumption
Suspect Areas:
  • Exhaust gas recycling valve
  • Particle filter overloaded
  • Electrical harness
  • Connectors

Fault Code: P0299
Description of Fault: Charge pressure regulation: Air pressure below the reference value.
Description of the diagnostics
For an engine speed between 750 and 4500 rpm and an engine torque higher than 75 Nm, the turbocharged air pressure measured is 300 mbars lower than the reference value for 8 seconds (Thresholds weighted in relation to the engine speed, the load, the atmospheric pressure and the air temperature at the air flow sensor).
Conditions of activation of the diagnostics
The following conditions have to be met:
- Engine speed above 800 rpm
- Engine torque higher than 75Nm
Conditions for Fault to clear:
  • Driving for 5 minutes
Downgrade Modes whilst Fault is active:
  • Reversible deactivation of the vehicle cruise control
  • Deactivation of the request for regeneration of the particle filter from the diagnostic tool
  • Switching of the turbocharging pressure regulation to controlled mode
  • Switching on of the warning lamp and/or warning message: Warning lamp MIL
Symptoms:
  • Jerking/stalling
  • Noise
  • Lack of power
  • No automatic stopping of the internal combustion engine
  • Smoke from the exhaust
  • Slightly higher fuel consumption
  • Starting problem
  • Fluid leak/smells (diesel fuel, oil, etc.)
  • Loss of braking
Suspect Areas:
  • Atmospheric pressure sensor in the engine management ECU
  • Clogged air filter
  • Air temperature sensor at the air flowmeter
  • Leak between turbocharger and air mixer
  • Leak between air mixer and engine inlet (including EGR take-off)
  • Manifold air entry pressure sensor
  • Turbocharger
  • Turbocharger fixed geometry control electrovalve
  • Turbocharger fixed geometry position repeat sensor
  • EGR valve
  • Oil
  • Sump
  • Oil suction strainer
  • Oil pump
  • Lubrication circuit of the turbocharger
  • Vacuum pump
  • Vacuum circuit leak
  • Electrical harnesses
  • Connectors
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Marc
jmr10
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Re: Needing advice with several fault codes

Post by jmr10 »

Thanks, I will look into the EGR fault. Do you know if there is any common issues that I could check first for code U1401?
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Re: Needing advice with several fault codes

Post by GiveMeABreak »

The LIN network wire from the alternator to the Engine ECU should be checked:

On the Alternator there should be a 1 pin and 2 pin connector.
On the 2 pin black connector, Pin 1 (marked) is the LIN that goes (via an interconnection) to pin 37 on the 53 pin black connector at the engine ECU:
C3 a51 alt lin.png
1020 is the alternator
1320 Engine ECU
C3 a51 alt lin loc.png
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Marc
jmr10
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Re: Needing advice with several fault codes

Post by jmr10 »

Thanks, do you know what resistance/voltages to expect?
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Re: Needing advice with several fault codes

Post by GiveMeABreak »

If the connections are good, it may be the alternator, as the LIN is what the BSI (master computer) uses to communicate with other ECUs on this network. The BSI can interrogate the alternator and get certain information, such as make & model of the alternator, the excitation current, rotation speed, temperature etc. It's a data network so may need special equipment to read. If you have Diagbox or Lexia, you may be able to read some live data on it, but if it can't get anything from the alternator, it may need replacing - as per the fault diagnosis info above.
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Marc