Robbo149 0 Posted January 2, 2004 The story so far... been having running probs with me VR - stuttering when warm generally not too happy etc., thought I'd tracked it down to a poorly air flow meter, so managed to get hold of a couple of s/hand ones from a local VW specialist to try. Did an ECU reset in between trying them but lo & behold the car drove exactly the same with them all! So next step, took it along to my local heroes who have the full Bosch diagnostic kit for a psychic reading... 1 error - 0203 Hall Sensor open circuit/positive short. I'm assuming this is the cam position sensor (G40)?! Thing is, I can't understand why the car drove exactly the same with or without the MAF connected :? Could it be that with a faulty Hall sensor, the car would be running bad enough for the MAF to make little difference? Corrados... they're grrrrrrreat! Quote Share this post Link to post Share on other sites
dr_mat 0 Posted January 2, 2004 It's certainly feasible. The MAF sensor is backed up by the throttle position sensor, so a failed MAF can be worked around for the most part, but a failed cam position sensor can't - it'll drop the timing so far back that it'll drive pretty poorly. It's relying on the crank position sensor, and that's too far from the cams to be any real use for fine-tuning the timing. Or so I think. I'll leave it to one of the experts to back my pure speculation up with facts! :) Quote Share this post Link to post Share on other sites
Joe M 0 Posted January 2, 2004 With the cam sensor knackered the ecu will be running in a back up mode so probably isnt taking any readings from the maf, the cam sensor is fairly cheap and easy to replace. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted January 3, 2004 Yeah Matt's right, the ECU just rolls back to a fixed timing map in the event of a CPS failure. The CPS gives 'on the fly' timing and when it's dead, the ECU retards the igntion to remove any possiblity of detontation. You lose 30bhp straight away but it's not until you give it some at the top end that you really notice it to be honest. The MAF is still interrogated to provide the correct fuelling though. I'm assuming yours is a coilpack model? I only ask that as you normally get a "XXX - Cam position sensor - implausible signal" error when it's lost it's resolution. Never seen a Hall sender error on a coilpack VR before but that could just be the difference between VAG-COM and VW 1551. K Quote Share this post Link to post Share on other sites
Robbo149 0 Posted January 5, 2004 Yeah Kev, it is a coilpack model. The error report may be different as the garage I used has a Bosch machine which does diagnostics for a variety of manufacturers not just VW, the error code on VAG-COM may use different terminology... Unless it's not the CPS of course!!!... I'm pretty sure it is though, what else could a "Hall Sensor" be? Robbo Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted January 5, 2004 Yeah Kev, it is a coilpack model. The error report may be different as the garage I used has a Bosch machine which does diagnostics for a variety of manufacturers not just VW, the error code on VAG-COM may use different terminology... Unless it's not the CPS of course!!!... I'm pretty sure it is though, what else could a "Hall Sensor" be? Robbo That is the CPS then, probably just what the Bosch diag software refers to it as. VAG-COM is more helpful as it tells you exactly what it's reading the fault code from, rather than using generic terms. K Quote Share this post Link to post Share on other sites
Robbo149 0 Posted January 5, 2004 Ordered a new CPS from the local stealer (shouldn't call 'em that really, my local VW dealer is actually pretty good & the parts guys are really helpful - JCT600 in Wakefield BTW). £32, & hopefully problem solved, I'll let you know. The extra horses would be nice too! Robbo Quote Share this post Link to post Share on other sites
