Corsa stepper motor

My wife has a 1.o gls 1998 model corsa with the following symptoms -
stepper motor constantly resets and does not contact the throttle lever
and the Voltage fluctuates constantly thus affecting cold starting.

Does any one know what sensors drive this motor through the ecu or how
it operates on an electical level. The ecu light on the dash does not
show a fault . I have read that this could be a fault on the circuit
board in the ecu. Also do I have to get the ecu repragrammed/reset for
the adaptive learning of the motor or does it do this itself?

Any ideas

 

i'd check the throttle pot or position sensor for dirt first if fitted.


mike

 

Thanks for the TPS tip, it appears that when i start the engine with
the throttle a degree or two open the stepper motor works as it should.
Tried to clean the TPS and it worked for a second but reverted back to
sending the incorrect Voltage. I will probably just replace it but do I
still need to have the ecu reset?

 

these often give trouble - they have been modified and come with a modified
wiring harness when you buy from a dealer - don't know if you can get
pattern parts. Cost about £150 I think. No reset needed, easy to fit but
clean the throttle butterfly while you are there.

 

glad to help.

The throttle position sensor (TPS) is particularly sensitive to resistance -
this is how it operates! I found that my engine management light was
illuminated - when check the ECU was finding low voltage from the TPS (code
22). After replacing the sensor (really awkward job!) the fault continued. I
traced the problem to be in the engine wiring harness. There is a main
multi-plug under the plastic plenum on the left hand side which seems to get
very hot when the engine is running. I found that with this unplugged there
was no resistance between one side and ECU and other side and TPS. However
when plugged together there is a few ohms resistance present. When there is
a current across the leads the resistance may well increase
Anyway the fix : Take out all the pins and solder each one of the crimpings.
My has never given me any trouble ever since.

mike

 

Just to let yall know in a last ditch attempt flooded the throttle
position switch with contact cleaner and blew it out with compressed
air. Now it idles at 1200rpm without the stepper motor making
contact(motor still resets constantly) I will buy a new tps from
vauxhall at the weekend for a princly sum of £61.99 not including vat
and also check the wiring loom and connectors for resistance and
corrosion as suggested.

Thanks for all your help and advice

 

well if your going for broke and you don't need the motor .
crack it open and check the wiper is making good contact.
(it's only a variable resistor like a volume control anyway)
well i say that, though i've only ever done one vauxhall one,
but i have done other motors and there are two versions to my knowledge.
one is a wiper, the other is a spring ballbearing or brush.

worst case is you might find the track has been worn away, then sadly your
sunk.
however, to me, it sound like the wiper might just not be making contact and
need bending in a bit.

if the track is only worn in a tiny place then a bit of conductive paint
'might' get you out of trouble.

mike




Just to let yall know in a last ditch attempt flooded the throttle
position switch with contact cleaner and blew it out with compressed
air. Now it idles at 1200rpm without the stepper motor making
contact(motor still resets constantly) I will buy a new tps from
vauxhall at the weekend for a princly sum of £61.99 not including vat
and also check the wiring loom and connectors for resistance and
corrosion as suggested.

Thanks for all your help and advice