Power Steering Dangerously Light On Motorways

[Mat07]

Hello all,

 

I think C5s are supposed to have Progressive Power Steering ( "PPS" ), getting progressively firmer on higher speeds, but I think my C5 is not doing that, or not enough anyway. It remains very light, even at 70mph.

 

Yesterday on a double lane A road with just a slightly uneven surface it required constant concentration and effort to keep it on a straight line - very stressful, and even dangerous, IMPO. I had to reduce the speed and travel at between 60 and 65mph. And even on good motorways I would prtefer a firmer steering at higher speeds.

 

Googling about it today I couldn't find any info on C5s. On a American forum, someone mentioned that his Lexus PPS's "Vehicle-speed-sensing" could be malfunctioning, something to do with a "solenoid"? That poster wrote: "I really don't like this. You could sneeze hard and crash this sucker!"

 

Well put!

 

Is the Progressive Power Steering on C5s adjustable? Tunable?

 

Thanks in advance for any help,

 

Mat

[Parkesie]

A few generic causes of the symptoms youve got can be over inflated tyres tracking out of alignment/ a worn ball joint or wish bone bush/bearing.

[paul.h]

Welcome to the forum.

 

Which year and model of C5 is your car ? I've had a 2004 C5 hatchback and now a 2007 C5 estate and not found anything unusual about the steering, so possibly there is something wrong with your car/tyres and Parkesie has listed the things you need to check. What make and size of tyres do you have on all the wheels, are they worn evenly, and as already noted, are the pressures at the value shown on the front door pillar sticker and have you checked your tyre pressure gauge against another to check its accuracy (ones that are part of a foot pump can be way out) ? If you take your hands off the steering wheel does the car continue to go in a straight line or does it pull to one side ? Are the wheel bolts tight ?

 

If the tracking is out then the car could steer all over the place - I replaced a steering rack on a Saab once, and set the tracking as best as I could but until I had it set properly the car had a mind of its own at any speed and wet manholes and more than about 30 mph had to be avoided.

[Mat07]

Parkesie, these are all fine. The steering is not loose, it doesn't have a play. It is just too light, over-assisted, because this assistance doesn't decrease at higher speeds, as it is supposed to do with a Progressive Power Steering ( "PPS" ) system.

 

I'm starting to wonder if C5s do have PPS at all. I had assumed that all cars had it, for the past 10, if not 20 years. Perhaps not??

Edited October 30, 2014 by Mat07

[Mat07]

Hi paul.h,

 

Thanks,

 

2005, facelift model.

 

Good tyres, Michelin, correct size and pressure, worn evenly, with hands off the car keeps a straight line - as long as the road is absolutely flat, no side-wind, etc.

 

It is just too light, over-assisted at speed.

 

Does anybody know if C5s have PPS at all?

[madmadmax]

most spedo drives are now digital so yes it could have some kined of system, if you give me the lats 8 digest of yous vin number i can check to see if you car has variable power steering

 

 

the next thing to check is the torque sensor

 

have you noticed if the stering is lighter in one direction?

 

i would get it pluged in to see if its got any codes stored on the bsi

[paul.h]

According to the Haynes manual, there are 2 types of power steering, one using a pump driven by the auxiliary belt and one on some facelift models (2004 to 2008) using an electric pump/ecm fitted under the right front wing. The electric one provides power assistance when needed and can be varied in relation to vehicle speed/steering wheel angle rate of change. Both use the lds fluid from the suspension lds tank.

 

 

The following is from Citroen's procedures which suggest the power assistance is variable on both types of pump by varying the fluid pressure and on the belt driven one is by the pump or an electro valve - so there may be a fault to look for and a diagnostic check may be able to show the fluid pressure to see if it is being regulated or possibly show a fault with the pressure switch. There is also a thrust pad on the steering rack which could be replaced.

 

3.2. Power steering pump

Reducing flow power steering pump(engines EW7J4, DV6TED4 and DW12TED4).

The power steering pump is driven by the accessories drive belt.

The power-assistance varies as a function of engine speed(the flow decreases as the engine speed increases).

Regulation pressure : 100 to 5 bars.

Pulley diameter : 129 mm .

 

Constant flow power steering pump(engine version ES9A).

The power steering pump is driven by the accessories drive belt.

A proportional electrovalve, incorporated in the valve, modulates the steering assistance as a function of the vehicle speed.

Regulation pressure : 100 to 5 bars.

Pulley diameter : 129 mm .

 

Power steering electropump assembly(engines EW10 and DW10BTED4).

(12)LDS fluid reservoir.

(13)High pressure piping.

(14)Distribution valve.

(15)Steering mechanism.

(16)Low pressure piping.

(17)Power steering electropump assembly.

The flow provided by the power steering electro-pump varies as a function of the following parameters :

• Vehicle speed
• Speed of turning the steering wheel

Regulation pressure : 100 to 5 bars.

 

 

If you are going to go under the car make sure you use axle stands - see this post http://www.citroen-owners-club.co.uk/citroen/topic/15220-always-use-axle-stands/

 

[coastline taxis]

check your front ride hieght sensor for signs of siezing. The bhi unit should lower the front end of the car at 65 to 70 to increase handling. it cant if the r/h/sensor dosnt let the ecu no where its at

[madmadmax]

paul.h that is corect but you have to have a car that has that equiped other wise you have non verabul power stering. thers no point trying to falt fined a system thats not there.

 

a good call from costline on the hight sensors a bit of wd 40 or the like will work for that job

 

paul.h if you look on citroen service box you will fined a tab called caristristics in the tap is gives a full spec of the car and in that it will say UNVARIABLE POWER STEERING or VARIABLE POWER STEERING,  now if you use this vin 76601060 it will spec UNVARIABLE POWER STEERING so there are evedentley two types of power stering used.

[paul.h]

This is copied from the characteristics for our 2007 C5 2.2 hdi VTX estate which shows it has unvariable power steering but it has electrohydraulic steering which should be variable - but it is confusing :

 

 

 

STEERING - UNVARIABLE POWER STEERING

SUSPENSION - NORMAL SUSPENSION

ACTIVE SUSPENSION - HYDRACTIVE SUSPENSION 3 PLUS AUTO ADJUSTMENT

DYNAMIC STABILITY CONTROL SYSTEM - ELECTRONIC STABILITY PROGRAM

STEERING (OPERATION) - ASSISTED ELECTROHYDRAULIC STEERING

[Mat07]

most spedo drives are now digital so yes it could have some kined of system, if you give me the lats 8 digest of yous vin number i can check to see if you car has variable power steering

 

 

the next thing to check is the torque sensor

 

have you noticed if the stering is lighter in one direction?

 

i would get it pluged in to see if its got any codes stored on the bsi

 

Thanks madmadmax,

 

Last 8 numbers: 76713342

 

I think it equally light in both directions, but i'm not sure. I'll check that next time I'm on a higher speed road.

 

Yes, I'll talk to our local Citroen specialist garage one of these days, to get it plugged.

 

By the way, when a garage plugs a C5, do they have to look for specific codes? Or everything wrong with the car will just pop-up? I'm asking this because last year they did plug it, but because of a different problem (some "Engine Management" fault warning). If the steering had already a problem back then would the steering code be also listed automatically and clearly visible when plugged? Or would the steering code be in some other place/screen or whatever? if you know what i mean.

 

Thanks again,

 

Mat

Edited October 31, 2014 by Mat07

[Mat07]

 

According to the Haynes manual, (...)

 

Wow, thank you paul.h!

 

But I'll need time to understand all that!

 

Don't worry i won't try to fix that myself. I'm just a car user. I may print your reply and take it to our local garage, along with all the other useful posts here.

Edited October 31, 2014 by Mat07

[Mat07]

check your front ride hieght sensor for signs of siezing. The bhi unit should lower the front end of the car at 65 to 70 to increase handling. it cant if the r/h/sensor dosnt let the ecu no where its at

 

That is very interesting too. Thanks coastline taxis. I'll ask my garage to check that.

 

Would a problem in that area have a code as well, if plugged?

[coastline taxis]

yes it will come up  front ride height sensor no signal or out of range. best way is to just remove the link bar and grease it

[paul.h]

If you use a garage that is not a Citroen specialist or Citroen dealer, then they may not have the required diagnostic equipment to check for anything other than engine management emission related fault codes. Specialists would use Citroen Lexia diagnostic equipment which will access all of the car. So it could be your garage may not be able to look for suspension or steering problems with their diagnostic equipment and last year when you had the engine management fault, if there was a steering/suspension fault then it would not have shown.

 

Remember to use axle stands if you go under the car and particularly if you touch the height sensor/its link rod since the suspension can quickly drop to a low level, only a few inches above the ground.

[madmadmax]

any garage should be abel to read the bsi for fault codes but there are some that only have low level stuff

 

hears your car mat07

 

STEERING UNVARIABLE POWER STEERING

SUSPENSION NORMAL SUSPENSION

ACTIVE SUSPENSION WITHOUT HYDRACTIVE SUSPENSION

DYNAMIC STABILITY CONTROL SYSTEM

ELECTRONIC STABILITY PROGRAM

STEERING (OPERATION) ASSISTED ELECTROHYDRAULIC STEERING

Edited October 31, 2014 by madmadmax

[paul.h]

In case this helps, from the VIN the car is a petrol C5 II 5 door hatchback 2.0 i 16v 143 manual gearbox 5 with the EW10A engine.

[Mat07]

yes it will come up  front ride height sensor no signal or out of range. best way is to just remove the link bar and grease it

 

ok, thanks coastline taxis.

[Mat07]

(...) Citroen specialist (...) Citroen Lexia diagnostic equipment (...)

 

Remember to use axle stands if you go under the car and particularly if you touch the height sensor/its link rod since the suspension can quickly drop to a low level, only a few inches above the ground.

 

The garage i use is supposed to be a Citroen specialist, buy i don't know if they have this equipment. I'll try to ask.

 

I won't try to do the job myself, but very good of you for spreading the word on this huge and surely fatal risk!

[Mat07]

any garage should be abel to read the bsi for fault codes but there are some that only have low level stuff

 

hears your car mat07

 

STEERING UNVARIABLE POWER STEERING

SUSPENSION NORMAL SUSPENSION

ACTIVE SUSPENSION WITHOUT HYDRACTIVE SUSPENSION

DYNAMIC STABILITY CONTROL SYSTEM

ELECTRONIC STABILITY PROGRAM

STEERING (OPERATION) ASSISTED ELECTROHYDRAULIC STEERING

 

Thank you madmadmax, that is very useful.

 

And really surprising. I remember my father in the 1970s talking about progressive power steering in American cars. I had no idea in this day and age cars would still fail to have it. Specially a car that is supposed to have 5 stars NCAP. A non-progressive steering, or "un-variable" in Citroen's language, is much less safe on higher speeds, even dangerous. I guess Citroen just plays by NCAP's rules to get their 5 stars, and save money in everything else... Shameful really. Some accidents may have happened already because of it, or even many accidents, who knows? Fatalities? Again, who knows?

Edited November 1, 2014 by Mat07

[coastline taxis]

If the citroen specalist dosnt have lexia diagnostic then hes not.

[Mat07]

If the citroen specalist dosnt have lexia diagnostic then hes not.

 

I see. Thanks again coastline taxis.