power steering

[ucb]

A1 dci 2014 power steering fault light on at start-up.

 

Typically, when the car has been stood for a few days at start up the power steering light comes on. After maybe 1 or 2 mins at idle the light goes out and power steering is restored.

Typical voltage readings that apply are Battery voltage                              
                                
at switch on there was no fault                                
                                
Battery charges to                     14.7            
                                
Switch off - battery drops to  after  a rest period                    12.7            
                                
engine off and full lights                     12.2            
                                
recovers after a period to                     12.4            
                                
A few days later:-                                
                                
at 12 degrees                    12.4            
                                
Cranking                    9.9            
                                
Then charging quickly to to                    14+        still no fault    
                                
After 7 days                                
                                
11/6/22023                                
                                
Temp                    18.5            
                                
ignition off voltage                    12.32            
                                
ignition on                    12.05        warning light  on    
                                
Cranking                    10 ish            
                                
seconds after start                     14.6            
                                
warning light out after about a minute steering ok                                
                                
idle voltage after 2 mins                     14.7            
                                
switch off and after 5 mins battery volts at                    12.86         

 

I ready some say it is due to a poor battery which may be but if the pump's specification for operating voltage is a nominal 12volts then I would expect the operation parameters be up to 15volts (  ie maximum charge from the alternator) and so taking the lower operational voltage to be a similar figure down to 9/10volts.

 

Any help with this one please and maybe some one has a wiring diagram to also indicate the cable terminal point?

 

Many thanks 

[Magnet]

Keeping it simple Bri, it sounds as if the battery has done its time. It’s voltage under load is the important parameter. 
Note - down to less than 10v at cranking. 
Kind regards,

Gareth. 

[ucb]

On 6/12/2023 at 7:49 PM, Magnet said:

Keeping it simple Bri, it sounds as if the battery has done its time. It’s voltage under load is the important parameter. 
Note - down to less than 10v at cranking. 
Kind regards,

Gareth. 

Gareth

Many thanks for your reply. Yes, battery may well turn out to be the issue but If the rated voltage for this unit is 12v and it must be capable of 15v to cover for a "charging" cycle" is it possible that its lower end spec would be 9v  ie operating voltage spec 12v+/- 3v. And so it should not "fault" out at 9v ?  Also if the battery is low why do other components not fault out?

 Battery may be cheaper than the pump?

Bri

[Magnet]

Bri, where does your stated 12v   +/- 3 volts come from? 
Kind regards,

Gareth. 

[ucb]

Gareth

 

Rule of thumb ish. The vehicle supply is a nominal 12v, if all is well a resting battery should be 12.8v. The charging system should quickly go to 14.5 ish to maybe 15v and then be controlled by a volts regulator. And so I expect that the steering pump will be cable of 15v at least and if it will handle (by specification) a plus 3v increment it would also handle a 3v down below the nominal 12v to 9v. I havent been able to get a full manufacturers spec on the pump, its all based on "general" practices.  

[Magnet]

Hello Bri,

To say it as I see it the +/- tolerance is correct only on the plus side, and I think your minus tolerance belief is based only on your assumption. 
Kind regards,

Gareth.