P0343 DTC P0343 Camshaft Position (CMP) Sensor Circuit High

**Camaro98Z/28** · 11-22-2010, 06:03 PM

DTC P0343 Camshaft Position (CMP) Sensor Circuit High Voltage

Ok I just replaced my short block mods below. I have changed the oil twice and have put 200 miles on the car. Today CEL came on with DTC P0343 Camshaft Position (CMP) Sensor Circuit High Voltage. Clearing and upon restart it comes right back so its def a problem. It is hard to start at times others it fires right back up but now always on start up it comes back. Connected my Matco Scanner and under the CMP low it displays 1 and under CMP high it displays 0. Do I have a bad cam sensor or a wiring issue? I have driven it the same route for the past 2 weeks and it just so happens on the first nice day instead of freezing cold this problem crops up.
Any direction would be appreciated guys, the sensor will be here Monday but I don't want to rip the intake off replace the sensor and have the issue still remain.

**Camaro98Z/28** · 11-23-2010, 05:47 PM

no one?!

**Camaro98Z/28** · 12-04-2010, 11:57 AM

Ok update
replaced the sensor problem continues, i checked both at the jumper by the EGR and the plug at the sensor and it does indeed positive and negative voltage at both points. I could not check the cam sensor signal input though. I was told I should replace the crank sensor but IDK, any help at all guys?!

**Cutlass** · 12-04-2010, 03:39 PM

test the signal wire (Brown/white) for a short to ground, short to battery postive or and open circuit. You could also test for continuity of the wire from the PCM to the Cam sensor connector.

**Camaro98Z/28** · 12-04-2010, 06:04 PM

Sorry I probably wasnt clear, I did indeed check that and voltage was between 11-12 volts which it states 7-17 is normal in the manual. I couldnt understand how to test for the 45-55% on the PCM ref signal so I skipped that and just tested for continuity which from the jumper to the sensor it passed (obviously from the jumper to the PCM I am unsure of but if you can walk me through how to use my volt meter to test the % I will do that before I go through the trouble of yanking the timing cover)
The more and more I search and read about this the more I think the cam may actually be backing out. The tach works and reads just fine but today when i finshed replacing the sensor it actually backfired on me. Upon reading alot more I found this is common among Z06 C5s, and I think I may of forgot to locktight the cam sprocket bolts when installing my TR224 into the new block.

I realize the mods never posted so here they are
TR224 114 LSA, LS2 Chain Gears & Trays, LS7 Lifters, Manley PRs, PAC Valve Springs, SLP Ported/Shimmed Oil Pump, SLP SS Hood, SLP SS Grille, SLP Lid, K&N Panel, SLP Bilstein Strut Spring Package, 1LE Front Sway, Circle D 3200 Stall, PS LTs & Y, Magnaflow Cat-Back, BMR ADJ LCAs and Panhard, TUNED BY JJS PERFORMANCE, Pioneer AVH-4000 HU, All Infinity Speakers.

**SteveC** · 12-07-2010, 03:36 AM

I am by no means an expert on this, could it possibly be a cracked reluctor ring on the end of the camshaft? I know there is a sensor that rotates at the end of the cam that has to pass in front of the sensor, maybe it is not, keeping the circut always open.

SteveC

**LS1Z28** · 12-07-2010, 07:18 PM

Did you do a crank position relearn when you replaced the short block or sensor? If you didn't that could set the code you are getting.

**Camaro98Z/28** · 12-14-2010, 04:30 PM

Thought i would let everyone know it turned out to be the cam walked. Cam gear bolts werent torqued properly and all 3 had come lose, moved out and were against the timing cover.
Checked the bolts, applied locktight re-installed and now everything is good as gold!

**28Marcos** · 04-01-2011, 10:58 PM

Originally Posted by Camaro98Z/28

Thought i would let everyone know it turned out to be the cam walked. Cam gear bolts werent torqued properly and all 3 had come lose, moved out and were against the timing cover.
Checked the bolts, applied locktight re-installed and now everything is good as gold!

dam! I hope thats not the case for me! going to replace my cam pos sensor in the am, hope thats as far as the problem goes for me!

**RONS98TA** · 10-15-2013, 03:30 AM

HOLY CRAP!! I def hope this isnt my issue. I installed a Procharger D1SC and recently got the cam pos sensor code. I replaced my sensor but also still have the prob. I really not looking forward to pulling my timing cover back off.

**RONS98TA** · 10-16-2013, 02:56 AM

Originally Posted by RONS98TA

HOLY CRAP!! I def hope this isnt my issue. I installed a Procharger D1SC and recently got the cam pos sensor code. I replaced my sensor but also still have the prob. I really not looking forward to pulling my timing cover back off.

Well nothing but good news folks. It turns out I had a broken wire in the connector where the EGR use to be. Took a butt connector to it and a lil silicon inside for weather protection, and ses light is fixed. Sure glad I didn't have the cam bolts backing out!