Weird one for you

[Benscab123]

So, to explain my situation..........
2010 1.6hdi gp
I have p1434 and p1435 along with p0401 and pO100.
Ocassionaly I was getting a turbo overboost, but this seems to have stopped now . Car stinks of what is either diesel fumes or exhaust fumes (I can’t tell which).
The car itself seems to run just fine, no limp mode, no misfire etc. But surely if there is a problem with the additive injection system it would not be regenerating ? Thus should be putting the car into limp mode ?
Can anyone help me with this please ?
Thank you.

[GiveMeABreak]

P1434: Particle filter additive system: Excessive temperature or open circuit. Basically saying excessive temperature on the power stage of the additive pump. Whilst you have this code the pump will stop doing its job and the additive ECU will stop calculating additive injected of course.

Ultimately, your particulate filter will start to clog if you do shorter journeys / interrupted driving where the conditions for natural regeneration cannot occur. Suspect is the additive pump.


P1435: Additive system: Additive system fault. The diesel fuel additive ECU (ADDGO)has a problem with communication on the CAN network. Same down grade conditions as I described for the previous fault. Suspect is still the Additive Pump.

P0401: Air system fault: Measured quantity of air higher than the setting. It's saying there is a discrepancy for 10 seconds between the air flow setting and the measured air flow.

The fault will go when the vehicle is driven for 5 minutes, remaining below an engine speed of 3000 rpm. This will resulting a lack of power, increased diesel consumption and noise. The MAF diagnostics for coherence will be deactivated whilst this fault is present.

There are a lot of potential causes for this fault, but I've emboldened the last point as it may have something to do with the particle filter getting blocked (because of lack of regeneration due to the additive pump fault).

• Electric exhaust gas recycling valve
• Air mixer
• Air flow meter
• Air leak after the compressor
• Air flow sensor information incorrect
• Vacuum problem
• Variable geometry of the turbocharger jammed in the "maximum turbocharging" position
• Turbocharging pressure sensor
• Clogging of the exhaust gas recirculation circuit

P0100: Flowmeter signal: Air flow not plausible. There is a negative difference of 200 to 300 mg/stroke between the measured air flow and the air flow reference value for 2 (for an engine speed higher than 1500 rpm).

These are the downgrade modes activated whilst this fault is present:

• Use of the flow calculated
• Inhibiting of the diagnostics and air flow sensor plausibility
• Cut-off: Cutting of the EGR butterfly (turbo air cooler), EGR valve and bypass butterfly (inlet air heater) in all operating modes
• Cutting of the "exhaust heat recovery" function
• Change to "easy move" torque invalid (Deactivation of automatic mode for the electronic parking brake)

Suspects:

• Electric exhaust gas recycling valve
• Air flow meter
• Air intake
• Turbocharging pressure sensor
• Electrical harness
• Leak of air downstream of the turbocharger

So I would check your additive pump first and then the MAF.

[Benscab123]

Thanks for your very detailed information Marc, much appreciated.

[Benscab123]

What I don’t understand is, I’ve done about 25,000 miles with these faults and the cars still running fine.

[Benscab123]

Replaced additive pump and P1434 and 1435 have now gone off. Going to replace the maf sensor next and see if that gets rid of the other 2. Thanks Marc.

[Stickyfinger]

Strong hint, ONLY use OEM MaF sensors....