Anti-Polution Fault / ESP/ASR disabled

[mooseshaver]

Have had the above fault twice now, and appears to be caused by cheap supermarket fuel, only 5 litres left in the tank, and wet weather.
Once I've put a better fuel in the problem goes away.
Anyone else had this problem?
Its a 2.2 HDi, almost 5 years old.

[KevMayer]

I get 'ESP/ASR faulty' sometimes for no apparent reason. If I turn off and back on it clears.

I got 'Anti Pollution Fault' once when I disconnected the small pipe from the top of the intercooler to the small pressure switch.

Kev

[mooseshaver]

Thanks, will get someone to check that for me.

[Fella]

Had serious problems with ESP/ASR faults which caused ESP to go into reduced power mode. Fault could be cleared by switching off ignition etc.. Helps if you can observe which fault comes on first and triggers off the other two. Cause of my ESP/ASR faults was burst membrane in air intake regulator.

[mooseshaver]

Well its not cheap fuel. Have been putting the expensive BP stuff in and have had the fault four times on two tanks.
The limp home mode clears after a short stop. But anti-pollution fault stay untill perhaps overnight or a couple of days. Then they often come back.
Its always the ESP/ASR that appears first, then the Anti-pollution. But after its been off the ESP/ASR vanishes and the Anti-pollution fault stays.

[AndersDK]

EEloy fluid issue ? (low or empty)

[Fella]

C5 2.2 hdi. One to try is to replace air temperature sensor located in front of air filter sensor as the sensor rusts and breaks. I found local "cheapie Citroen" supplier when I asked "Oh yes I sell loads of these for C5s" will need replaceing sooner or later - reason is that air intake is nearside Britain and offside France so sucks up lots of water on our roads !.

[KevMayer]

I read somewhere that a faulty air intake sensor can lead to high fuel consumption. The economy of my 2.2 Hdi isn't impressive so I may try a new airflow sensor.

How much are they ?

[mooseshaver]

[quote="Fella"]C5 2.2 hdi. One to try is to replace air temperature sensor located in front of air filter sensor as the sensor rusts and breaks. quote]

Ok, me and cars don't get on too well. Is it easy for a simpleton to replace? It sounds electronic, so that must be like a computer which is really my area. I've looked in the engine before when filling fluids and breaking off the screenwash cap. What tools would I need? I have none so should buy some generic ones anyway, might as well get a few car ones.

[mooseshaver]

EEloy fluid issue ? (low or empty)

Nothing has mentioned the Eolys, I think that has different message, and I had it topped up at the last service (not a citroen dealer), less than 10000 miles ago. But I could be wrong. Will have a look in the manual later

[Fella]

The part is listed as Air Mass Sensor and is between air filter and turbo. Checks air temp and volume of air passing through to turbo so if one of the sensors not working has bound to have an effect. Has electrical connector plug coming out of it. Is a screwdriver job to replace. I think it cost me under £60. The cause of my C5 2.2 HDI ESP/ASR and anti pollution fault
was eventually traced to a swirl control diaphram split. This was after 8 visits to main Citroen dealer and a burst turbo. No amount of previous electrical diagnosis showed this. Cost £13 for diaphram and £73 labour. Replacement turbo cost a bomb !!

[KevMayer]

Fella. Your split diaphragm sounds interesting. Where is it fitted ?

Is the swirl system you mention the set of flaps which open and close to change the air inlet ducting ? The flaps are linked together and the system activated by a vacuum solenoid.

Is the diaphragm in the vacuum solenoid or in the inlet manifold itself ?

cheers, Kev

[Fella]

Took details off bill for repairs so cannot say for definate where located. The symptoms with my 2.2 hdi were that the ESP/ASR came on with a steady throttle at 35 mph and 60 mph. By watching the speedometer I was able to drive past these speeds but in traffic when concentrating on road "Bleep bleep" then safety mode (50 mph); stop, switch off wait 20 seconds, restart with power restored. As stated before not diagnosed by diagnostic system even contacted Citroen HQ but received no help. Problem became worse and I issued ulimatum to Citroen Glasgow where strip down revealed fault.

[KevMayer]

I believe that the ESP/ASR and Anti Pollution fault occur if the turbo gives an overboost.

The turbo has two modes and the switch between the two is controlled by a vacuum operated solenoid.

From start up, the exhaust gas blows on a small area of the drive turbine. As the boost pressure increases a switch on top of the intercooler is triggered at a particular high pressure. When this switch operates it triggers an electrovalve which operates the vacuum solenoid to reveal more of the power turbine to the exhaust gas flow. The exhaust gas flow rate decreases over the larger area and so a lower boost pressure or lower rate of boost results.

Now, if the pressure switch on the intercooler fails, like mine did, or if the vacuum operated solenoid were slow to change the turbine profile, then a short overboost may result. There must be another sensor which monitors boost pressure which sees the overboost and trips the limp home mode to prevent further overboost occuring. This generates the ESP/ASR and the Anti Pollution alarms.

Now this is my theory from my experiences with my 2.2 Hdi. If anyone doesn't agree then that's ok. If you know how it works let us know.

If what I propose is correct then let us know too.

cheers, Kev

[mooseshaver]

My Car has gone in for MOT, service number 6, suspension service, so I have asked the dealer to fix the anti-pollution fault too. Will let you know what they find.