Date: 11 Apr 2007 11:45:34 -0700 From: "pzi" <pzinospamnet> Subject: Re: 9-3 viggen - Throttle Motor. Full PWM in Closing Direction
On Apr 11, 11:18 am, Colin Stamp <col.dust...nospamp.plus.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? > >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? > > PWM is "Pulse-Width Modulation". It's the method the ECU uses to > control the amount of force the motor applies to open and close the > butterfly. Both codes seem to be different levels of the same problem > - the ECU is having to drive the motor harder than expected to close > the throttle. Full PWM would mean that the ECU has had to turn the > motor power up to maximum when trying to close the throttle, and it's > still not enough. > I don't think it'll be the throttle cable, since that's not involved > in actually moving the valve unless the "limp-home" solenoid is > engaged. > It would have to be something about the throttle body itself, like a > sticking butterfly. I would check everything you disturbed around the > throttle body. Is it possible that it might not be bolted down flat so > it's a bit distorted? > > Cheers, > > Colin. The only parts that I disconnected from the throttle body was the limp- home solenoid - I unscrewed it completely since I could not disconnect the connector, 10-pin throttle body connector and two hoses. I left the throttle body bolted to the intake manifold. I will try to wiggle all connectors and maybe apply some electric contact spray. I will also clean the valve itself with the cleaning solution I have from my volvo throttle body procedure... thanks -Peter
