PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban - The 1947 - Present Chevrolet & GMC Truck Message Board Network

shultzee13 · 05-21-2016, 08:20 PM

Replaced the distributor cap and rotor on my 5.7L 2WD Suburban (98) and now I am getting a code P0340 Camshaft sensor circuitry. I was VERY careful to put it all back and not budge anything. I originally had a P0300 and found that my rotor had actually broke off at the tip. I replaced it and now this…. ENG1 fuse still good and nothing I've googled has fixed it. I did pull a few spark plugs and they have a white tip from overheating. Bad spark plugs cause this code to set? Thanks
BTW - I did replace cap and rotor with AC DELCO OEM

speedygonzales · 05-22-2016, 08:18 AM

Did you do the cam retard process?

That won't cause this issue but it needs to be done. More than likely the module in the new distributor is bad. If you still have it, put the old one in it. Don't forget the heat sink compound under it. If you want, I'll post how to test them later. I have to run.

speedygonzales · 05-22-2016, 12:06 PM

I seriously doubt you now have a wiring issue after changing the distributor but you could probe 2 of the 3 wires going to it.

With the distributor disconnected and key on, probe the pink/black wire from battery positive. You should see battery voltage. Or if you use a test light with the clamp on the positive battery terminal, probe the pink/black wire and it should light.

Now move the clamp lead to the negative battery post and probe the solid pink wire. Light should be on or meter should read battery voltage.

The only other wire brown/white goes to the PCM. You could check continuity from one end to the other.

shultzee13 · 05-22-2016, 10:12 PM

Thank you sir. I will test this tomorrow and post back. Thank you for all your help!!

I sincerely appreciate it as always

shultzee13 · 05-23-2016, 11:23 PM

I have 12 volts power and ground to the sensor and the MAF sensor on the same circuit, fuse good as well.

speedygonzales · 05-24-2016, 06:46 AM

As I mentioned earlier, I doubt you developed a wiring problem from simply changing the distributor. However, we all have trouble knowing if the actual pins in the connector are making contact.

Swap out the modules, be careful if heat sink compound is needed. If all goes well, set the cam retard and go from there.

05-21-2016, 08:20 PM	#1
shultzee13 Registered User Join Date: Jan 2012 Location: Tyler Texas Posts: 223	PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban Replaced the distributor cap and rotor on my 5.7L 2WD Suburban (98) and now I am getting a code P0340 Camshaft sensor circuitry. I was VERY careful to put it all back and not budge anything. I originally had a P0300 and found that my rotor had actually broke off at the tip. I replaced it and now this…. ENG1 fuse still good and nothing I've googled has fixed it. I did pull a few spark plugs and they have a white tip from overheating. Bad spark plugs cause this code to set? Thanks BTW - I did replace cap and rotor with AC DELCO OEM

05-22-2016, 08:18 AM	#2
speedygonzales Registered User Join Date: Jan 2006 Location: Smithfield, VA Posts: 1,501	Re: PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban Did you do the cam retard process? That won't cause this issue but it needs to be done. More than likely the module in the new distributor is bad. If you still have it, put the old one in it. Don't forget the heat sink compound under it. If you want, I'll post how to test them later. I have to run. __________________ 99 Z71 (98 body style) Pride and joy

05-22-2016, 12:06 PM	#3
speedygonzales Registered User Join Date: Jan 2006 Location: Smithfield, VA Posts: 1,501	Re: PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban I seriously doubt you now have a wiring issue after changing the distributor but you could probe 2 of the 3 wires going to it. With the distributor disconnected and key on, probe the pink/black wire from battery positive. You should see battery voltage. Or if you use a test light with the clamp on the positive battery terminal, probe the pink/black wire and it should light. Now move the clamp lead to the negative battery post and probe the solid pink wire. Light should be on or meter should read battery voltage. The only other wire brown/white goes to the PCM. You could check continuity from one end to the other. __________________ 99 Z71 (98 body style) Pride and joy

05-22-2016, 10:12 PM	#4
shultzee13 Registered User Join Date: Jan 2012 Location: Tyler Texas Posts: 223	Re: PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban Thank you sir. I will test this tomorrow and post back. Thank you for all your help!! I sincerely appreciate it as always

05-23-2016, 11:23 PM	#5
shultzee13 Registered User Join Date: Jan 2012 Location: Tyler Texas Posts: 223	Re: PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban I have 12 volts power and ground to the sensor and the MAF sensor on the same circuit, fuse good as well.

05-24-2016, 06:46 AM	#6
speedygonzales Registered User Join Date: Jan 2006 Location: Smithfield, VA Posts: 1,501	Re: PO340 Camshaft Circuit - 5.7L Vortec 2WD Suburban As I mentioned earlier, I doubt you developed a wiring problem from simply changing the distributor. However, we all have trouble knowing if the actual pins in the connector are making contact. Swap out the modules, be careful if heat sink compound is needed. If all goes well, set the cam retard and go from there. __________________ 99 Z71 (98 body style) Pride and joy



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