Clutch Position Sensor Volvo V70

Clutch Position Sensor Volvo V70

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Discussion

Tunku

Original Poster:

7,703 posts

242 months

Friday 27th April 2012
quotequote all
Does anyone know what exactly the CPS does on a V70 that has no cruise control, no ignition lock out or anything else I can think of? It's a 2001 P2 V70 140hp Torslanda B5244S2 with manual transmission.
I replaced mine because it was showing an error on the driver message centre (no OBD code - needed Volvo kit), and it was contaminated by brake fluid. I put the new one in and driving the car does seem to be easier at low revs, more control over revs when clutch is half in, smoother when on no throttle slowing at parking speeds. Is this a placebo effect, or is the bloody CPS actually used on my car?

stevieturbo

17,746 posts

261 months

Friday 27th April 2012
quotequote all
It probably doesnt do anything important. But the simple fact it is there, and the ecu expects it to be there. If it isnt or is faulty, the ecu can revert to a limp mode which can affect how the engine runs

anonymous-user

68 months

Friday 27th April 2012
quotequote all
stevieturbo said:
It probably doesnt do anything important.
er, right. Well, actually competely wrong tbh, sorry ! ;-)


The clutch position switch is used (in conjunction with the NOVS calc (N over VS, or RPM over vehicle speed, which is a valuve that is gear dependant)) to swap the torque control modes around depending on driver inputs.

So with the clutch down, in neutral, at the traffic lights, the idle speed control will have full authority, and the dashpot controller and tip in control will be disconnected. Once in gear (NOVS telling the system what gear you are in) the torque ramps and OSMOD (active driveline torque oscilation damping) is engaged, and the negative torque tip out ramp and absolute value become gear dependant.


What this all means is that the car will now have the driveability attributes that the OEM has calibrated. With a failed CPS then the car probably defaulted to a 1st gear or possible neutral gear driveability functions. Not at all ideal for every other drive mode!

Tunku

Original Poster:

7,703 posts

242 months

Friday 27th April 2012
quotequote all
Max_Torque said:
stevieturbo said:
It probably doesnt do anything important.
er, right. Well, actually competely wrong tbh, sorry ! ;-)


The clutch position switch is used (in conjunction with the NOVS calc (N over VS, or RPM over vehicle speed, which is a valuve that is gear dependant)) to swap the torque control modes around depending on driver inputs.

So with the clutch down, in neutral, at the traffic lights, the idle speed control will have full authority, and the dashpot controller and tip in control will be disconnected. Once in gear (NOVS telling the system what gear you are in) the torque ramps and OSMOD (active driveline torque oscilation damping) is engaged, and the negative torque tip out ramp and absolute value become gear dependant.


What this all means is that the car will now have the driveability attributes that the OEM has calibrated. With a failed CPS then the car probably defaulted to a 1st gear or possible neutral gear driveability functions. Not at all ideal for every other drive mode!
Well, fk me! You are telling me that it does make a difference. It does feel like it does. Smoothness is the only answer I can give, and it feels like it accelerates better, which is odd, because the clutch is put to bed well before that. Pratting about at parking speeds is a lot better, it's more like a diesel now, like my old 740 was, lots of torque just at tick over so you can use the clutch with no throttle to go back and forth.

stevieturbo

17,746 posts

261 months

Saturday 28th April 2012
quotequote all
Max_Torque said:
er, right. Well, actually competely wrong tbh, sorry ! ;-)


The clutch position switch is used (in conjunction with the NOVS calc (N over VS, or RPM over vehicle speed, which is a valuve that is gear dependant)) to swap the torque control modes around depending on driver inputs.

So with the clutch down, in neutral, at the traffic lights, the idle speed control will have full authority, and the dashpot controller and tip in control will be disconnected. Once in gear (NOVS telling the system what gear you are in) the torque ramps and OSMOD (active driveline torque oscilation damping) is engaged, and the negative torque tip out ramp and absolute value become gear dependant.


What this all means is that the car will now have the driveability attributes that the OEM has calibrated. With a failed CPS then the car probably defaulted to a 1st gear or possible neutral gear driveability functions. Not at all ideal for every other drive mode!
Who would have guessed !!! lol

anonymous-user

68 months

Saturday 28th April 2012
quotequote all
Yeah, and in 2012 it's even worse! (more complicated)

A typical Ford/PSA/JLR product will now have

1) Clutch master cylinder position sensor (absolute pedal position sensor)
2) Clutch pedal bottom "depressed" switch
3) Clutch pedal top "home" switch


All in the aim of improving driveability! (and in a lot of cases furnishing Stop-Start capability)


The simple rule of thumb is "If it's fitted to your car, it's doing something" as OE's hate spending money on stuff they could delete (even if it's 35pence for a clutch switch!!)

stevieturbo

17,746 posts

261 months

Sunday 29th April 2012
quotequote all
If the need this many driver aids for basic stuff.....those drivers should buy automatics !

Obviously it is market led, but it is a surprised automatics arent more popular.

One of my cars was a very basic old automatic, and I loved driving it ( general commuting of course )

If I could get my van with a decent automatic that was as easy or better on fuel than the manual, I'd have one in a shot.
They dont even offer an auto though for my engine, and not a chance in hell would I buy one with the stty Fiat engine.

Tunku

Original Poster:

7,703 posts

242 months

Sunday 29th April 2012
quotequote all
Max_Torque said:
Yeah, and in 2012 it's even worse! (more complicated)

A typical Ford/PSA/JLR product will now have

1) Clutch master cylinder position sensor (absolute pedal position sensor)
2) Clutch pedal bottom "depressed" switch
3) Clutch pedal top "home" switch


All in the aim of improving driveability! (and in a lot of cases furnishing Stop-Start capability)


The simple rule of thumb is "If it's fitted to your car, it's doing something" as OE's hate spending money on stuff they could delete (even if it's 35pence for a clutch switch!!)
Thank you for your explanations Max_Torque. Quite amazing stuff. I cut my teeth on contact breakers and manually adjusting dwell angles etc. when tuning my first cars. Your last comment is confirmation that something on the car is using it! Thanks again thumbup