ECU errors P0494 and P0299

[krle59]

Peugeot 508 SW VF3**************[VIN obfuscated, can be read by forum staff] 2012. 252.000Km 1.6 thp 115KW
When driving, check engine started, engine showed lack of power.
Diagnostics showed errors P0494 and P0299 .
When the errors are eliminated, the engine runs normally, until it turns them on again while driving.
Does anyone have any idea what is going on and if these errors are related to each other or is it a coincidence.
I appreciate every reply.

[GiveMeABreak]

Here's a description of those faults for you:

Fault Code:	P0494
Description of Fault:	Fan assembly status signal: Coherence. Possibility 1: Incoherence between the reference value and the copy value; 5 s after the excitation of the cooling fan (Fan unit 1 or 2/3 speeds). Possibility 2: Lack of coherence between the reference value and the repeat value for more than 5 s (Variable speed fan assembly). Conditions of activation of the diagnostics The following conditions have to be met: - Engine management ECU in main triggering phase - Fan unit 1 or 2/3 speeds : Slow or fast speed activated - Variable speed fan assembly : Control unit active
Conditions for Fault to clear:	The following conditions have to be met: - Fan unit 1 or 2/3 speeds: 5 s after the excitation of the cooling fan, the return signal is at the high status - Variable speed fan assembly: Control unit closed (The return signal is at the low status for more than 5 s)
Downgrade Modes whilst Fault is active:	Activation value for the cooling fans sent on the CAN for the air conditioning set to the default value 126% Deactivation of the air conditioning Engine coolant temperature alert on the CAN
Symptoms:	Lack of power Engine overheating Possible stopping of passenger compartment cooling by the air conditioning
Suspect Areas:	Electrical harness Cooling fan unit control relay Electric cooling fan unit Engine fusebox Engine ECU

Fault Code:	P0299
Description of Fault:	Turbocharging circuit: Pressure too low. Turbo pressure too low: Turbo regulation at the minimum limit. The difference between the reference turbo pressure and the actual pressure falls below the threshold of -0,1 bars or -0,12 bars if there is an error in the camshaft dephasing system. No confirmation time Conditions of activation of the diagnostics The following conditions have to be met: - Engine management ECU in main triggering phase - Turbo regulation active - Atmospheric pressure higher than 0,8 bars - Engine speed above a threshold dependent on atmospheric pressure - Turbo pressure valid - No power step error
Conditions for Fault to clear:	The following conditions have to be met: - Must be within 8 s after the appearance of the fault (Deactivation of the turbo regulation 8 s after the appearance of the fault) - After engine restart (If the difference between the reference turbo pressure and the actual pressure exceeds the threshold of - 0,1 bars or - 0,12 bars if there is an error in the camshaft dephasing system)
Downgrade Modes whilst Fault is active:	Deactivation of the turbocharger regulation (Electrovalve forced wide open) No authorisation of checking of the power stage of the dump valve Reduction of load applied to revert to the behaviour of a naturally-aspirated engine (The maximum load is limited by the mapping : 110 % to 2000 rpm ; 40 % to 6500 rpm)
Symptoms:	Lack of power
Suspect Areas:	Turbocharger pressure regulation electrovalve Turbocharger discharge electrovalve Vacuum pump Air cleaner Air inlet line Turbocharger boost sensor Vacuum circuit Turbocharger pressure regulation capsule

[PaulC5]

When our C5 came up with P0299 it was the MAP sensor that was bunged up with oil. Using live data on a code reader showed its value did not alter much when the accelerator was pressed which gave it away. Fixed with a new sensor and cleaning out its connection on the manifold. Cleaning the old sensor with carb cleaner caused extra fault codes so cleaning was not a fix in my case.