Camshaft Position Sensor
97Sierra4x4
03-01-2005, 01:14 PM
I have a 1997 GMC Sierra 4X4. My "service engine soon" light came on and if I give my truck too much gas, it lurches real hard. So I went to Advance and they scanned and came up with this:
Camshaft Position Sensor A - Bank 1
Circuit Malfunction
MIL REQUESTED
Since IGN NOT RUN
Since Clear FAIL
I installed a new electro-mechanical actuator on Saturday and when I got done is when the service engine light came on. I assumed I must have disconnected something when I was running the new wire (I don't know how considering it takes an act of congress to pry apart a connector). I have looked and looked and can't find anything disconnected. Any ideas? HELP!
Camshaft Position Sensor A - Bank 1
Circuit Malfunction
MIL REQUESTED
Since IGN NOT RUN
Since Clear FAIL
I installed a new electro-mechanical actuator on Saturday and when I got done is when the service engine light came on. I assumed I must have disconnected something when I was running the new wire (I don't know how considering it takes an act of congress to pry apart a connector). I have looked and looked and can't find anything disconnected. Any ideas? HELP!
SpitAndDirt
03-03-2005, 01:46 AM
Exactly what Electro-Mechanical type thing-a-ma-bob did you install? What was the part called or it's part #? What was the exact code that was pulled? Have you messed around with the distributor at all recently? Technically, there is no camshaft position sensor, in the normal sense of the term. The "camshaft position sensor" is actually the pickup inside of the distributor. Our motors do actually have the Crankshaft position sensor mounted to the front of the timing cover just behind the harmonic balencer. If you have for some reason tried to time your motor in the traditional method you would have offset what the computer is reading. I think GM calls it Cam Retard or Cam Offset. It can only be adjusted using a very high quality scan tool, such as the dealers Tech 2, Snap-On, Matco, or OTC. You need to be able to see what the computer is seeing and then adjust the distributor back into alignment. What you are trying to do is synchronize the distributor and the crank sensor together, the computer will handle adjusting the timing curves. It can't do its job until the two are in their proper positions. But all that means nothing until we know what the code was exactly. I hope this leads you to an answer. And, like I tell all the rest of the people I post to, check out your VIN at this website and see if you have any available computer updates to be flashed into your computer. Some drivability issues can not be fixed by throwing parts. http://calid.gm.com/vci/VINEntryPre.do Take this information to the dealer and find out what it will cost to have your computer updated. This is the only time I suggest you go back to the dealer, but I do not believe that it should cost more than $150 -Chris 96 Z71 5.7L All Stock
Jeremy-WI
03-04-2005, 10:49 AM
I'll bet he replaced his thermal front axle actuator with the new style, but that would be no reason for the code he supposedly has, unless he hooked the brown wire from the new actuator wiring harness to the wrong wire(instead of hooking it to the brown wire at the transfer case switch)
97Sierra4x4
03-04-2005, 11:08 AM
Yeah, it was the new-style actuator for the 4WD. I realize that it and the camshaft position sensor have nothing to do with each other. It just seemed like a strange coincidence. I spliced the wire to the right wire because I had a local transmission shop (that I have used and trust) check it out afterwards. I've never messed with the timing on this truck because my Haynes manual says "Ignition timing cannot be adjusted on 1996 and later SFI engines". I made an appt to have it checked out on Monday. I will post a reply after that. Thanks for your help and suggestions!
97Sierra4x4
03-22-2005, 02:00 PM
I put a mass air flow sensor on it and that helped a little with the idling problem but it was still lurching. I took it to my Chevy dealer and they replaced the wiring to the camshaft position sensor and that fixed it. It runs better than it has in the last several months so it was apparently there before I replaced the actuator and this problem coming up at the same time was just a coincidence. Thanks for your help.
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