Throttle Body - 2020 6.6 Sierra- service bulletin

[Rewopleahcim]

Has anyone encountered throttle body issues? Mine  is a 2020 Sierra , a week old, 250 KMS on it. Went into limp mode a few days back. Dealer told me there is a service bulletin for these trucks. I was told it was the second one this week. It's now at the dealership waiting for parts. 

[SkidooSteve12]

I haven't heard anything about throttle body issues on the 6.6L gas motor. I have 6400 miles on mine without any issues.

[redwngr]

Don't know what temps the OP's truck was running in, but there is one for rough running at temps below  -10F (_23C) and lower temps.

 

Rough Running Engine in Extreme Cold Temperatures

January 30, 2020

A 2020 Silverado HD or Sierra HD equipped with the 6.6L V8 engine (RPO L8T) may have a rough idle or reduced engine power in very cold climates (-10°F or -23°C). The Check Engine lamp may be illuminated along with DTCs P0123 (Throttle Position Sensor 1 Circuit High Voltage) and P0222 (Throttle Position Sensor 2 Circuit Low Voltage) set. These engine performance conditions may be caused by an internal circuit fault within the throttle body.

If these conditions are found on a vehicle exposed to extreme cold, replace the throttle body assembly following the service procedure in the appropriate Service Information. (Fig. 10) In addition, add a ground wire using two 8 mm ring terminals and one 8-inch piece of 14-gauge wire.

 

Fig. 10

 

To install the ground wire, remove the oil cap and engine cover from the rocker cover on the left bank of the engine. Attach one end of the ground wire to the lower-right throttle body fastener with the crimp side of the ring terminal facing the bolt head. (Fig. 11)

 

Fig. 11

 

Attach the other end to the rocker cover fastener with the crimp side of the ring terminal facing the bolt head. (Fig. 12)

 

Fig. 12

 

Once the ground wire is installed and secure (Fig. 13), clear any DTCs and road test the vehicle to verify the repair.

 

Fig. 13

 

Refer to #PIP5706 for additional information.

[Rewopleahcim]

20 minutes ago, redwngr said:

Don't know what temps the OP's truck was running in, but there is one for rough running at temps below  -10F (_23C) and lower temps.

 

Rough Running Engine in Extreme Cold Temperatures

January 30, 2020

A 2020 Silverado HD or Sierra HD equipped with the 6.6L V8 engine (RPO L8T) may have a rough idle or reduced engine power in very cold climates (-10°F or -23°C). The Check Engine lamp may be illuminated along with DTCs P0123 (Throttle Position Sensor 1 Circuit High Voltage) and P0222 (Throttle Position Sensor 2 Circuit Low Voltage) set. These engine performance conditions may be caused by an internal circuit fault within the throttle body.

If these conditions are found on a vehicle exposed to extreme cold, replace the throttle body assembly following the service procedure in the appropriate Service Information. (Fig. 10) In addition, add a ground wire using two 8 mm ring terminals and one 8-inch piece of 14-gauge wire.

 

Fig. 10

 

To install the ground wire, remove the oil cap and engine cover from the rocker cover on the left bank of the engine. Attach one end of the ground wire to the lower-right throttle body fastener with the crimp side of the ring terminal facing the bolt head. (Fig. 11)

 

Fig. 11

 

Attach the other end to the rocker cover fastener with the crimp side of the ring terminal facing the bolt head. (Fig. 12)

 

Fig. 12

 

Once the ground wire is installed and secure (Fig. 13), clear any DTCs and road test the vehicle to verify the repair.

 

Fig. 13

 

Refer to #PIP5706 for additional information.

The dealer replaced the throttle body and added the ground wire. I now have about 400kms on the truck, with no further issues so far. Hopefully this was a permanent fix.  Average temperature for this time of year is -30 , -40 Celsius.

[redwngr]

5 minutes ago, Rewopleahcim said:

The dealer replaced the throttle body and added the ground wire. I now have about 400kms on the truck, with no further issues so far. Hopefully this was a permanent fix.  Average temperature for this time of year is -30 , -40 Celsius.

Saw Canada as your location and wondered if maybe you were far enough north that the bulletin would apply.

 

Rarely get below 0F 'here'.

[SkidooSteve12]

Oh boy.... part of the reason with getting a gas truck was so I had the reliability in sub-zero temps on trips where the truck will sit for several days. The last trip the temps were down to -10* F but I didn't have to run the truck then. It was in the single digits I think when we did drive the truck and it ran fine.

 

I guess this will be something I need to discuss with my dealer to try and have done before I am in a situation where the truck goes into limp mode while pulling my snowmobile trailer on a trip.