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GMC Forum: P1345 Camshaft to Crankshaft correlation faulty
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Old 05-15-2010, 03:15 PM is offline
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Default P1345 Camshaft to Crankshaft correlation faulty

I hooked my 1997 sierra up to a OBD Scanner and it reads that i have a P1345 code which is a camshaft to crankshaft correlation fault. Could it be a bad sensor or is it automatically my timing change that needs to be replaced?
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Old 05-16-2010, 11:55 AM
Molson02536 Molson02536 is offline
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Originally Posted by View Post
I hooked my 1997 sierra up to a OBD Scanner and it reads that i have a P1345 code which is a camshaft to crankshaft correlation fault. Could it be a bad sensor or is it automatically my timing change that needs to be replaced?
You are correct, the ECM has detected the timing from the crankshaft and camshaft is off to far to set off the DTC code P1345. It's more common for distributor gear to be worn then your timming chain. If your timming chain is stretched, you can hear it rattleing under hard acceleration.

The 1996 and newer Vortec is a non adjustable timing. There is a very good chance that replacing cam position or crankshaft position sensor will not fix this problem. This code tells you that the base timing of the vehicle is not correct. You really need to get the vehicle scanned with a scantool that will read the cam retard with the engine running over 1200 rpms and then make adjustments by turning the distributor, unless it is timing chain/gear stretch/wear or wear on the distributor gear. You could mark the current distributor orientation and turn the distributor counterclockwise, clear the code and start the vehicle and rev over 1200 rpm to see if it comes back, but the scan tool that can read the cam retard is the best way.

FYI The cam position sensor is in the distributor and the crankshaft position sensor is mounted to the bottom of the motor near the balancer. But i would look in to repalceing the worm gear at the bottom of the distributor shaft, the 97 and 98s, Vortec engine is that the gears were soft and they would actualy wear enough to through off the timing and you could try to adjust the timing but at some point you'll run out of adjustment. Also, the real big problem is that the gear is also hooked to the oil pump and at 75 or so, it may strat to mis-fire and backfire because the timing is so far off and the oil pump is also run off the same gear and your oil pump can fail.

This is a common problem with that vintage of GM distributors because you could usually adjust the timing enough to get the code to go away but you are just masking the real problem. Friend is a GM certified Tech, worked at an Olds dealer for 10 years before opening his own place, but he had never herd of this as being common. He then proceeded to show me a box with about 25 to 30 gears all worn the same way and all from 96 thruogh 99s that had SES lights on. And now with a $40 part and less than two hours labor and ten minutes on a scanner all these 100K mile trucks run fine and can pass E-Test.

Good luck and you really need a Tech2 scanner to get a better picture on why your getting a P1345 DTC code, but most likely it's going to be a $40.00 distributor gear.
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Old 11-03-2012, 11:02 PM
navarrodragon25 navarrodragon25 is offline
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Default p1345 code and cylinder one unaffected

I got a catalytic converter issue on my 1996 sierra 7.4 vortec with almost 300,000 miles.

It has new lifters,rods,cam,sprockets,chain,oil pump,stater,crank chaft sensor,cam shaft sensor,disributor cap,plugs and wires etc.

Not sure if it was caused by engine problem related to this code but I was told that if I don't fix this code issue then a new converter could be ruined.

At any rate, even though the engine rides perfectly smooth most of the time (after some major engine work) it will get Hot under the hood (even though the thermostat gauge shows a good temp) after about 20minutes and it will hesitate and surge. All clues point to a bad converter clogging up causing back pressure and eventually causing it to totally bog down and die. Interestingly it does not do it as soon as I start it and is not continuous but only starts to have a problem after the 20 or 30 minutes.

I have heard clanking and rattling under the truck twice. Once seeminlgy by the converters(there are two and fairly close together) and once more close to the rear of the muffler.

QUESTION #1 If this were a "TIMING ISSUE" woudn't it ride rough ALL the time and not so smoothly when I first start it?

... and oddly today I happened to take OFF the spark plug wire to cylinder ONE while it was running and the engine continued to run fine and was totally unaffected.

QUESTION #2 What would cause the engine to run smooth with a spark plug wire off? ( I had a loose spark wire years ago and it idled horribly from the moment I started it up)

Question # 3 Would the spark plug situation be caused by or related to the P1345 Code? ..HOW?

When I finally fix the code problem THEN I will change the catalytic converter.

Last edited by navarrodragon25; 11-03-2012 at 11:20 PM. Reason: addtional
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