This problem has been haunting me for months. I have a 2004 cheverlet silverado 5.3L 220,000 miles. I've replaced coil packs, wires, plugs,maf sensor, map sensor, rocker arms, rods, lifters, camshaft, timing chain and gears, water pump, cmp sensor (twice), cmp pigtail, crank sensor and knock sensors. Think that's all. Now before I replaced the camshaft I had no p0342 code. Only after I replaced camshaft, cmp, crank and knock sensor code showed up. I only replaced certain things cause it easier to get to with motor dismantled. I do have scanner and dmm. I've tested wires to cmp,crank and knock sensors since they all share signal. I've done everything that I know how and what other mechanics have shared with me and now I'm at a loss and pulling out what little hair I do have left. Oh I just recently replaced the ECU. Any suggestions or comments would be greatly appreciated.

 

throwing parts at the problem rarely helps, but make sure you installed the correct camshaft

what are the other codes please?

I presume you're talking about the 5V reference?


For the benefit of anybody else trying to help:
The following conditions may cause this DTC to set:
• Camshaft reluctor ring damage • The sensor coming in contact with the reluctor ring • Foreign material passing between the sensor and the reluctor ring • Excessive camshaft end-play • Wiring routed too close to secondary ignition components


measure resistance between the sensors and your ECU, like he does in this video

 

First off I never was throwing parts at it to hopefully fix problem. My original problem I have fixed. I went ahead and changed the cmp crank and knock sensors because it was easier to change them out while I had easy access to them. I hv 220000 miles on motor so only matter of time before they go out. I have already check for resistance. .01 I do belive is good. As for camshaft I made double sure it was correct before ordering when it arrived it matched up with old one. Only other code is p0650 cause my check engine light went out.

 

I'm so confused. So what was fixed, and what is still not fixed?
Does the truck run?

 

Have a p0342 and a p0650 code. Yes truck does start and run it just has a hard start and about dies if don't keep foot on pedal. I have checked all wires for sensors all are good.

 

You checked all three circuits?
Measured resistance all the way back to the PCM connector?
Are you getting 12V on the red wire?

put your meter across ground and the brown wire (at the sensor end) in volts mode. slowly rotate the crankshaft with a breaker bar. You should see the voltage jump up and down between two values. (12V looks like)
https://www.aa1car.com/library/crank_sensors.htm

 

Signal and low reference had .03 resistance and 12 volt had .05 -.06. 12 volt wire was at 11.75 but that's what was in battery. Checked brown wire it does jump up and down when turning motor over.

 

ok that all checks out.
Maybe it's an intermittent problem. try wiggling the wires around and see if the signal drops out.

 

First off you mention you have to keep your foot on the pedal so it does not die, and the engine is hard starting.

Have you checked the fuel pump pressure and have you also pulled off the vacuum line going to the fuel pressure regulator to make sure the internal diaphragm in the fuel pressure regulator has not failed? If it did fail, as soon as you remove the vacuum line, gasoline will pour out of it.

Also here is a link regarding the P0650 code:

https://www.gmforum.com/obd-ii-troub.../p0650-286007/

Good Luck!

 

"with motor dismantled"

ok maybe your timing chain is off? there are two marks on the harmonic balancer that's a source of confusion.

there's a great video on youtube for positioning distributor timing for mechanical re-assy of that (unsure it can cause the code?). but anyway that is a source of confusion also.

"The two symptoms of the P0650 code are either the MIL not turning on when it needs to or the MIL being illuminated when it doesn’t need to be. PCM itself or connections to it could be included". however - loose wires (such as on the wiring pad between break pedal and parking brake, if loose, can be an issue - and i found my horn wasn't honking due to that break-out box exactly)

p0342 “Camshaft Position Sensor 'A' Circuit Low.”. I ASSUME you have a good battery AND volt thingy (regulator built into alternator). the PCM of any car will be spurious, the car have issues starting, if voltage is low across the vehicle.

Now will someone help me with my P0440! oh never mind. i'll drive it and get it inspected before it illuminates

ME? I'M BETTING YOU HAVE YET TO FIND YOU'VE DISCONNECTED a positive battery cable or ground connector somewhere or have a like a transmission connector unplugged - and that is throwing the cam code.

"has a hard start and about dies if don't keep foot on pedal". well: don't worry about that until you clear the code. you can't get proper fuel trim for "easy starting" if the fuel trim inputs are not being seen by the PCM. (the cmp is one of about 7 inputs for fuel trim / timing advance and effects "easy starting")

BTW: my 2001 chevy silverado has P0440 for 10 yr intermittent. i must crank it 2-3 revolutions. stop. then crank just 1-2 rev it starts right up. sometimes in summer it starts right up without all that. i've never found the cause. i checked the distributor 10x it does know where #1 is

i'm unwilling to spend like $300 or even $80 on parts and don't want to run down 10 parts to find the cause. in the old days there was no "quick start" and during the winter it was "standard procedure, if you had a physical distributor, to crank, stop, crank again - not crank too many revs".

for you - i don't like hearing you need your foot on the pedal to start. your fuel pressure should come up as you key-on. and the PCM should trim the fuel and advance. you have a mechanical throttle plate and that controls advance and fuel. (on cars and most trucks, the vaccum is adjusted by throttle and the fuel is adjusted to the sensed vaccum). i just assume your odbii told you your MAF is reading the right intake air temperature and all. PROBLEM? for starting you shouldn't have your foot on the pedal if you have a PCM.

for you: you have two "circuit low" codes. that hints at a loose wire somewhere. you could have cmp low if crank is installed wrong idk. but having two "circuit low" doesn't make sense.

what is your parasitic amp draw?

are you sure your voltage regulator (built-in to alternator) is working? are you sure you DON'T have an aftermarket radio or damaged radio causing crazy grounding?

did you do your dilligence on cleaning and tightening all grounds in engine compartment and rear chassis? you definitely should whether or not you have codes - occasionally

you said you replace the ECU (PCM). wow. it's allot of stuff you replaced. good job on that at least you don't give up and eventually you'll find a silver lining in just the fact of keeping up not giving up.