didn't know there was such a thing.
Are you getting a code? If so what is it?
Are you getting a code? If so what is it?
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Please provide more information! 
what you copied/pasted from SI (its kinda butchered a bit, there are some incorrect statements above) above does not apply to the duramax....or any classic full size GM truck for that matter. Unless its a 2009+ with stabilitrak. Or an 02-05 truck with quadrasteer.
(fyi, its VSES, Vehicle Stability Enhancement System)
Also, if you can find me a picture of a PSCM on a GM full size truck/SUV Ill be very VERY impressed...
ben
ok couple things that are incorrect...no offence but I would find a more accurate service manual.
First of all, the main correction that needs to be made to your statements. C0640 DOES NOT EVEN APPLY TO THE GMT-800's OR -900's. It is a code that applies to vehicles that have EPS, electric power steering...such as the malibu, HHR, some saturns, some cobalts, newer GM small cars etc...
second. Our trucks DO NOT HAVE A PSCM. They never have and never will (at least not within the next 5 years). The PSCM only exists for vehicles with EPS, as I said above. They have a regular old hydraulic power steering setup, same as cars have had for the past 50 years...in the new half tons its a rack and pinion, and the past and present HD trucks its a recirculating ball setup, same as its always been since the 70's. The only thing remotely related to this is the old VES (variable effort steering) system that was on the 95-98 GMT-400's...
Third. The SWPS (steering wheel position sensor) is wired directly to the EBCM (abs module). It doesnt make any 'stops' along the way.
The SWPS uses digital square wave signals, you cant check these types of signals with a multimeter on the "ohms" setting! It would be like trying to play/listen to a CD on a record player. The only analog signal coming out of the SWPS is when the steering wheel is perfectly on center.
There are only SIX wires coming out of the SWPS, not 8...
You really cant diagnose this properly without a tech 2. The only thing your multimeter is good for is checking the phase wires/on-center analog wires for shorts to ground or +12v.
The only GMT-800 pickup trucks that have a SWPS are the trucks with quadrasteer. fun fact: VSES (stabilitrak) in GMT-800 pickup trucks was tested some by GM engineers, but it was never actually offered in production GMT-800 pickup trucks. VSES was standard on the 2002+ escalades (although in 2002 only it was a kinda ghetto crude 3-channel system), standard on 2003+ denali's, and optional on 2004+ tahoes/suburbans. All GMT-900 SUV's have it standard.
By 2008 it was standard on GMT-900 light duty pickup trucks. In 2009 it became standard on 2500HD short bed pickup trucks (another fun fact: the GM's were the first HD trucks ever offered with an electronic stability control, ford and dodge still do not offer anything in terms of stability control).
This summer when the new 2011 GM HD's come out with the updated chassis, VSES will be standard on ALL single rear wheel HD pickup trucks, which is a great idea IMO.
SO. Basically. To the original poster...your truck doesnt have quadrasteer or VSES (stabilitrak), so therefore it DOES NOT even have a SWPS........
hope that helps clear things up...
Ben
I think you may be right.SO. Basically. To the original poster...your truck doesn't have quadrasteer or VSES (stability), so therefore it DOES NOT even have a SWPS........
hope that helps clear things up...
Ben
The book in the area involving Steering Sensors sucks. It is the GM Tech Manual
It has another separate section on the Steering Sensor for the Electric Steering, which the index points you to. There is no index reference to this circuit being tied the ABS system. Having 7 books and thousands of pages, one is quite dependent on the index.Also, they use a couple different types of sensors. However, all have variable resistors, as well as switches for pulse circuits. Some of the circuits in each sensor, shown in the book, can be tested for resistance. Also, even the pulse circuits can be checked for Open when it supposed to be open, shorts to ground, etc., by doing resistance checks. Switches and Pots are electo-mechanical and are the most likely part to fail. Not everyone needs to be dependant on a Tech II to find isolated problems. Anyway, ...
I am learning this circuit as we go. Never had a problem with it in the past. It is good to have people who actually have torn into these problems speak up and provide the detailed information versus just saying; No, thats not right. We all learn by kicking these kind of discussions around and the bumps keep it in view until we find the right person, and it is resolved.
Thanks for the useful information! Maybe that will put this thread to rest, at least for me. I learned a lot about this circuit
arrgh no they dont.
They use a digital phase position (PLL) sensor for reference. That is NOT THE SAME as an analog voltage potentiometer.Phase-locked loop - Wikipedia, the free encyclopedia
the steering wheel position sensor does have an additional analog sensor, but it is not for VSES use and basically doesnt do anything. Its only for the BCM (not the EBCM) to have a rough idea where the steering wheel is pointed. Analog sensors arent really accurate/reliable enough for something as critical as VSES references. If that [basically useless] analog sensor does fail, nothing happens. No check engine light, no ABS lights, no stabilitrak warning lights, nothing. It might set a code in the BCM (not EBCM) but you arent going to find that unless you have a tech 2.
to read the digital phase position signals (the only ones that really matter and are 'mission critical') you need a tech 2....like I said.
what GM tech manual are you using??? The only SWPS's that are analog like you mention are the old-school VES (variable effort steering, not VSES) and the magna-steer systems used in the mid/late 90's.
ben
Got the GM Tech Manual for the '09 2500 HD part number is GMT/09-CK9PU.
They show Analog Potentiometers on all three schematics. But, the schematics are specific to the "Vehicle Stability JL4" portion of the ABS system. So I think you guys are right.
There are a couple codes C0455 & C0710 that address this component. The one that applies depends on the GVW.
Yes, a Tech II would make things easier. But you would be surprised what a retired Instrument and Control Tech can do with a signal generator, scope and mutimeter.
They show Analog Potentiometers on all three schematics. But, the schematics are specific to the "Vehicle Stability JL4" portion of the ABS system. So I think you guys are right.
There are a couple codes C0455 & C0710 that address this component. The one that applies depends on the GVW.
Yes, a Tech II would make things easier. But you would be surprised what a retired Instrument and Control Tech can do with a signal generator, scope and mutimeter.
ok...if you really want to still argue about this...
DTC C0710 17: Steering Position Signal Shape/waveform Failure
DTC C0710 55: Steering Position Signal Expected Number of Transitions/events not Reached
DTC C0710 5A: Steering Position Signal Plausibility Failure
DTC C0710 0F: Steering Position Signal Erratic
Now, what part of those above descriptions has anything to do/describes a sort of analog potentiometer? Shape/waveform failure, number of events not reached? That doesnt sound like anything to do with a pot to me......
Im sure you could partially diagnose some problems with your equipment, but then again there are so many things that are "impossible" to diagnose/fix without a tech 2 though reading live GMLAN/class 2 data streams from modules... Like if the radio on a current GM truck/suv isnt outputting the correct volume to the speakers on a for a given volume position, how do you diagnose that without a tech 2???
ben
that manual isnt bad, but doesnt cover half of what SI does (the online dealer service manual) and ive seen more than a couple of errors in them...
that is incorrect, as Ive said above.
C0455 is for light duty's and hybrids. If you read C0710, you'll that there are several descriptions:
DTC C0710 17: Steering Position Signal Shape/waveform Failure
DTC C0710 55: Steering Position Signal Expected Number of Transitions/events not Reached
DTC C0710 5A: Steering Position Signal Plausibility Failure
DTC C0710 0F: Steering Position Signal Erratic
Now, what part of those above descriptions has anything to do/describes a sort of analog potentiometer? Shape/waveform failure, number of events not reached? That doesnt sound like anything to do with a pot to me......
well, sort of...you can also install programs onto your windows PC manually from the command prompt...and you can also fill up a semi's tires with a bicycle pump!Yes, a Tech II would make things easier. But you would be surprised what a retired Instrument and Control Tech can do with a signal generator, scope and mutimeter.
Im sure you could partially diagnose some problems with your equipment, but then again there are so many things that are "impossible" to diagnose/fix without a tech 2 though reading live GMLAN/class 2 data streams from modules... Like if the radio on a current GM truck/suv isnt outputting the correct volume to the speakers on a for a given volume position, how do you diagnose that without a tech 2???
ben
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