Date: Thu, 12 Apr 2007 23:45:33 +0100 From: Colin Stamp <col.dustbinnospamp.plus.com> Subject: Re: 9-3 viggen - Throttle Motor. Full PWM in Closing Direction
On 12 Apr 2007 14:20:02 -0700, "pzi" <pzinospamnet> wrote: >On Apr 11, 4:09 pm, Dave Hinz <DaveH...nospaml.com> wrote: >> On 11 Apr 2007 08:30:34 -0700, pzi <p...nospamnet> wrote: >> >> > I get check engine light with two fault codes: 1260 and 1251 after I >> > took the cylinder head off to change the head gasket. >> > The first one 1260 is the "Throttle Return Spring. Too Low Force" and >> > the second one 1251 is "Throttle Motor. Full PWM in Closing >> > Direction". I understand the first one but what is PWM in the >> > second? >> >> Take a look at the spring on the left side of your throttle assembly, >> where the cable from the pedal goes in to it. There's a spring there >> which can be adjusted. lift up the tail on the left /bottom (little tab >> of spring sticks out), rotate the black plastic assembly in the >> direction that adds spring tension. Start with one notch. Not sure I >> can describe the base setting of mine without pictures. >> >> > When this happens I feel a bit of rough operation of the accelerator >> > pedal. I think this may be the accelerator pedal wire dirty or >> > damaged. Strange is that this does not happen all the time - all >> > clear for 30 min of driving and then it is. I read the codes and >> > clear them and its ok for next 30 min. Any other ideas? >> >> I'd say that since you have the means to read and clear the codes, >> adjust the mechanical problem that you can, and see if the other code >> goes away. The throttle assembly isn't too much of a PITA to replace >> but it's not cheap. The local specialist told me "sometimes resetting >> it takes care of things" but obviously that doesn't address the root >> cause of why it jumped a notch in the first place. >> >> Let us know what you find, please. More data we have on this beastie >> the better. >> >> Dave Hinz > >I took the electrical connectors apart (limp solenoid, 10pin throttle) >sprayed with electrical cleaning spray and put them back and the ride >to and from work went without any faults at the cpu. >I was very gentle with the car and did not accelerate too much like I >did the first time (full throttle to say 100mph). I will try that >again on the weekend when I don't need the car to commute to work. >Thank you all for comments - I feel like I am learning from you guys! > >Also, Is there a good description of the Saab throttle body operation? >I am kind of lost with butterflies, limp homes, etc. I am interested >in the limp home mostly since I may have distrubed it. > >cheers - Peter Well basically, it's like this... The cable from the pedal operates the pedal arm. This turns sensors so the ECU knows how much power you want. The ECU then controls the throttle motor which actually opens the throttle disk (the butterfly). The pedal spindle and the throttle spindle should be separate from one-another normally, so with the ignition off, you should be able to move the pedal arm and the throttle spindle won't follow that movement. In limp-home mode, the solenoid does something which locks these two spindles together, so the throttle just follows the pedal position, and the motor can't make any difference. I've just had a look in the manual, and what I didn't realize before is that the throttle body actually latches itself into limp-home mode when the solenoid is triggered, and it needs to be manually re-set. If you just clear the error codes without re-setting limp-home mechanism, "trouble codes P1263 or P1251 will be generated". So, it looks pretty certain that your throttle body is latched into limp-home mode. Here's the procedure to reset it. http://www.stamp.plus.com/temp/Limp_home_reset_1.jpg http://www.stamp.plus.com/temp/Limp_home_reset_2.jpg When you've finished, moving the pedal arm with the ignition off shouldn't cause the throttle spindle to move. Cheers, Colin.
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