Knock Sensor on 6.2L issue

Murrayville · September 18, 2020

Well, I thought it might be a few years before coming to a forum to seek some help!

I currently have a 2019 GMC Sierra SLT with 4x4, standard box length, 6.2L engine with tow package added, at around 20000kms (around 12K miles?) And I have been running premium fuel in that beast since day one.

My engine made a few pinging noises one day while going up a small hill, then the MIL engine light came on. It hasn't made those noises since. I took it to the local dealer to scan, but the first time they took it in, they did a programming upgrade (recall) to the computer before scanning it for codes, so it erased all history and cleared the MIL engine light. About a month later, the light came on again, no engine noise this time. I took it back to the dealer, due to COVID regulations I couldn't be in the vehicle when they scanned it, so that service advisor cleared the light and codes. (Double piss-of now) It came on a third time, after 2 weeks since it cleared and it was the Knock sensor again.. This time I wouldn't leave the truck while they diagnosed with the scanner.

Code: P0328 - Knock Sensor Circuit High bank 1

It has been in the shop now for 4 working days, and the advisor called me today:

-They took a fuel sample and sent it to the lab for GM to confirm I had been running premium fuel in the truck.

-They believe that there may be a "parasitic draw' on the wiring harness from the ECM to knock sensor

-They found lower than normal voltages at the knock sensor

-They have wait to be advised by GM Canada to go ahead to replace the wiring first, then the knock sensor and the possibly the ECM if the lower voltage doesn't rectify

Yikes...

Would a faulty knock sensor cause pinging in the engine?

Apparently with this model year and config there has been two vehicles previously exhibiting these conditions. One was from an individual running a higher than normal ethanol blended, lower octane fuel. The other had wiring harness issues. Apparently there is no specific TSB related to this exact issue, although wiring harnesses seem to pop up in question in other threads.

I will keep the thread updated. Any insight appreciated.

Cheers,

Andrew

Murrayville · October 7, 2020

Well.. after a week and a half in the shop, they replaced one knock sensor. Two weeks later, it’s back in the shop with the same trouble codes and engine MIL on.

This time around they will be replacing the engine wiring harness and the ECM. Of course, they’ll have to order parts in.

vancealot29 · July 27, 2022

Hey Andrew,

Any luck with this issue? My check engine light came on today, got it scanned, and P0328 came back. This is actually the second time this code has come up in the twelve months I have owned the truck. The first time was directly after a car wash, and it down poured at my house yesterday for at least sixty minutes, so it has to do with the sensor getting moisture. In both instances, the light went off after a few hours.

Just curious to see how your issue was resolved.

Thanks in advance,

GMCustomerService · July 29, 2022

On 7/27/2022 at 1:50 PM, vancealot29 said:

Hey Andrew,

Any luck with this issue? My check engine light came on today, got it scanned, and P0328 came back. This is actually the second time this code has come up in the twelve months I have owned the truck. The first time was directly after a car wash, and it down poured at my house yesterday for at least sixty minutes, so it has to do with the sensor getting moisture. In both instances, the light went off after a few hours.

Just curious to see how your issue was resolved.

Thanks in advance,

This is certainly not what we like to hear, vancealot29. Please know, customer satisfaction is extremely important to us. Our team would be more than happy to take a closer look into the concerns with your truck. To do so, please send an email to [email protected] with ATTN: vancealot29/GM Trucks in the subject line.

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