Manager Forum

I have this 2012 Chevy K1500 Silverado with a 5.3L engine and automatic transmission. The truck came in with a no-start. Upon diagnosis, when the ignition key is turned on, there is a loud rapid clicking from under the hood. The PWR-TRN relay in the underhood power distribution center is chattering, the throttle body and the canister purge solenoid valve are clicking at a rapid rate also. If I disconnect the canister purge solenoid valve, the chattering stops. Plug the wiring harness back in, it starts again. So long as the canister purge valve is disconnected, I can start the engine and drive the truck around. With the canister purge solenoid valve plugged in, the engine will not crank over. The system is dead. Unplug it and instantly it has power and works fine.

So, thinking the canister purge valve is at fault, I ordered a new one. No difference. Same thing. What am I missing? Has anyone ever run into this?

I haven't looked at any diagrams yet, but is it possible you have a short somewhere in the wiring to the purge valve?

OK. I had a chance to do a little research. It's possible you are getting some back-feeding through the solenoid. P1682 is for a more than 3 volt difference between output voltages at the ignition switch. There have been reports of bad switches on these. I would check the outputs of the ignition switch and see if any are missing or low.

Ok, as soon as I can, I'll get the truck back in and check the outputs from the ignition switch.

Thanks Ric for your input.

To update this frustrating truck.

After more time of diagnosis, I concluded that the PCM is at fault. So, I contacted our local dealer and scheduled it for them to replace the PCM and program it. The service writer said that it could be something else though. I agreed.

They replaced the PCM, programmed it and that fixed it. Service writer said this series of trucks us having many PCM's replaced for this exact problem.

Happy technician and happy vehicle owner!!