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 FAQ #231
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C4, DS4 and C4 Picasso - Common Problems
What are the common problems across the C4/DS4 range?

The various engine components such as sensors, injectors, fuel pump etc. are supplied by a computerised fuse box in the engine compartment. This means that if it develops a fault - usually intermittent, it can cause various fault codes to be stored in the engine computer, ABS computer, parking brake computer etc etc.

Now you don’t know which faults are true and which ones you must ignore. Experience is your only hope, so if you have random symptoms or fault codes, it may be worth replacing the engine bay fuse box, also known as the BSM, PSF or similar acronyms.

All the above can also be caused by a failing battery. If yours is 4+ years old, change it 1st.

Broken Dipstick?

There is nothing as disconcerting as pulling out to find the end missing. After all it's that bit on the end that makes the whole thing a viable tool. With out the end, it's just, ...a stick.

So you've lost the end, and dipping seems pointless now. To the point that you'd probably not even bother any more. But don't give up just yet. There is hope. You are not alone.

It's a common problem unfortunately, and one of the biggest worries is "What of my end? Where is it, and will it do any damage?" Here's what to do:

Procure a new dipstick, carefully slide it into the tube. If it seats right down into it's normal parked position without having to use excessive force then all is well. The broken end will have dropped into the sump. It can't do any damage down there so don't worry about it.

If however you feel resistance then the broken piece is stuck in the tube and will need to be fished out or pushed down. Don't be tempted to use the new dipstick to ram it down, as this will probably break the new one too. Alternatively use some stiff flexible wire to poke the end back down into the sump. If neither of these methods work then you will need to remove the dipstick guide tube and attack from the other end.

Citroen Pneumatic Suspension

[C4 Picasso C4 Grand Picasso]

There is much talk about this problem. No doubt you have already trawled the net for a glimmer of hope - like many others, to little avail.

The pneumatic system as employed by PSA on these vehicles is sadly fraught with problems. Thankfully Citroen have recognised the problem and will pay toward the cost of repairs - Click Here -

However if you would prefer to return the car to conventional springs, Eurocarcare charge to the rescue with a foolproof conventional spring conversion kit..

Premier Members of C4owners can get the kit at a special discounted price.

Vacuum circuits

Turbos, throttle flaps, EGR valves, air heat exchangers, swirl valves – some of the many actuators who’s movement is controlled by a vacuum circuit.

They can be difficult to diagnose quickly. A faulty actuator or solenoid valve will affect the operation of the component it is associated with BUT it may also affect the operation of other actuators because it can cause a loss of vacuum available to other actuators, so you can easily be mislead by the symptoms.

Some actuators only work under certain driving conditions which are difficult to re-create in the workshop. It is possible to test all the solenoid valves, their electrical and vacuum circuits and actuators but it is time consuming and requires a vacuum gauge and pump and also the relevant diagnostic computer.

A visual check of all the pipework is advisable because the pipes can rub on moving parts or get burnt. If the fault is permanent, you can use a vacuum gauge to great effect, testing for sufficient vacuum at the reservoir and testing for vacuum at the actuator, but you always have to remember that a lack of vacuum can mean more than one thing- a leak, faulty actuator or faulty solenoid valve or electrical circuit. Access to parts can be awkward, particularly some turbos, and you do need to know which way round various systems work- some turbos need full vacuum for full boost and some require vacuum to be applied to open a waste-gate, some turbo waste-gates are operated by turbo pressure and have no external control. Substitution of parts is sometimes the easiest way but be careful that the part is identical as there are a few distinctly different solenoid valves. It is worth checking that pipes are the right way round on solenoid valves – it is usually marked on the valve which is the vacuum and which is the outlet.

Turbo problems

Have you had your engine management light come on or experienced a lack of power or strange noise from your car? It could be that you are suffering from a common turbo fault.

On the slightly earlier engines there has been a problem with compression gases leaking past the injectors and causing a build up of carbon around the injector, an audible blow from the cylinder and even foul acrid fumes getting into the cabin.

With the later engines the same leak of compression gases is occurring but the carbon is ending up in the engine oil via the rocker cover, piston rings or valve stems. Over a period of time even with proper servicing the oil quality is degraded and carbon blocks the oil strainer affecting the turbo spindle bearings.

This can and has caused complete failure of the turbo and a knock on affect of throwing lots of oil and broken bits of turbo into the complicated air induction system. When all this happens, the turbo and oil strainer need replacing and the induction system stripping and cleaning. Obviously this is an expensive business.

Prevention of course is always better than cure so you should always have oil changes carried out in line with the service schedule.

If your vehicle is still in its warranty period then this matter should be taken up with your dealer.

Grinding, 'graunching' noise when parking/turning

Many cars with Macpherson strut front suspension will suffer this one at some time or other. Due to the design the front suspension including coil spring must rotate with the wheel when steering. To facilitate this the coil spring is mounted on a roller bearing. Over time these bearings seize/rust/dry up/fall to bits. When this happens the spring is fighting against the seized bearing. If the bearing wins the coil spring will wind up like a clock spring and try to return the steering back to centre. If the spring suddenly wins it'll unwind with a big Twang or 'Boing' (in extreme cases a blood curdling Ping). The lead up to all this is general grating noises when parking etc. The cure is of course to replace the bearing.

Or, it could be a broken spring.

Why on earth is my heater / aircon hot on one side and cold on the other?

The air conditioning and heating seems to be cold on one side and hot on the other. This can be intermittent, choosing it's moments, which renders diagnosis frustratingly difficult. Alternatively, the dual climate control air distribution can become somewhat vague in operation. The cause of all this is due to the failure of a small piece of plastic. One of the flaps that controls air distribution mounted within the heater housing is driven by a beautifully under engineered plastic bar which after a period literally twists off.

However there is a cheap fix for this - Click Here -

Loss of power or intermittent no-go - HDi variants

Another fairly predictable fault due to lack of maintenance. The Fuel filter will be dirty and require replacement. The recommended change intervals are to long and you should look to change it every 25,000 miles or so. It's far cheaper to replace it than be stranded at the road side requiring recovery to a garage.

Heavy Fuel Smell

Smelling diesel inside the cabin can be caused by leaking injector seals. These should be checked and replaced a.s.a.p. as the fuel can leak into the sump, diluting the engine oil and potentially leading to very expensive 'turbo runaway'. There is a guide on site to injector replacement.

It could also be caused by a faulty valve on the charcoal canister system on the fuel return line. There is a tutorial on how to check and test it.

Erratic or surging whilst idling - petrol injection models

Some of the petrol models suffer a vibration or rough idle. This can commonly be sorted by replacing the stepper motor (also referred to as an idle speed motor, idle valve or motor) It might be worth trying to remove the unit and cleaning the solenoid. The fault usually returns after a while so the best cure is to just change it.

I go over a pothole or sleeping policemen I get a clunking noise!

The anti roll bar link (rod) ball joints have probably become worn or the 'drop links' have failed. Like any worn ball joint, the ball will rattle around inside it's cup when agitated. There is no cure other than to replace the rod. The vehicle will have an Anti roll bar running laterally across the suspension from one side to the other. The rod links the bar to the lower suspension arm or track control arm.

Thanks go to Mick and the team at Eurocarcare.net for some of the above.

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FAQ Posted by Dave_Retired.
Info Created: 03 December 2014
Last Updated: 14 June 2015