Rough Running GM Vehicle

Rough Running GM Vehicle

This condition may be caused by an internal circuit board fault within the throttle body.

Rough Running, Reduced Engine Power, Service Engine Soon (SES) Light On, P0123 AND P0222

Models

2020-2021 Chevrolet Silverado 2500/3500 w/6.6L 

L8T engine

2020-2021 GMC Sierra 2500/3500 w/6.6L L8T engine

A vehicle may come into the shop with a rough idle and/or reduced engine power. Upon inspection, you may find the SES lamp is illuminated and DTC’s P0123 and P0222 may be active or stored history. This condition may be more noticeable in very cold climates. Note: This PI is only applicable to failures that have resulted from vehicles being exposed to extreme cold, -10 Fahrenheit.

Cause

This condition may be caused by an internal circuit board fault within the throttle body.

Correction

If you encounter a vehicle with the above concern, it will be necessary to replace the throttle body and add a ground wire following the steps outlined below. Reference the attached pictures showing ground wire location. 

FIGURE 1
FIGURE 2

Repair Procedure

  1. Replace throttle body following the service procedure as outlined in service information.
  2. Using two 8mm ring terminals and one 8-inch piece of 14-gauge wire to make a ground wire as shown in Figure 1.
  3. Remove the oil fill cap and beauty cover from rocker cover on left bank.
  4. Attach one end of the ground wire to the lower right throttle body fastener with the crimp side of the ring terminal facing toward the bolt head (#1 in Figure 2), then attach the other end of the ground wire to the rocker cover fastener with the crimp side of the ring terminal facing toward the bolt head (#2 in Figure 2).
  5. Ensure that ground wire is secure.
  6. Road-test vehicle to ensure repair procedure is complete and clear any DTCs.

You May Also Like

Chrysler’s Totally Integrated Power Module

The TIPM is on the CAN bus, any issues with the communication between the ECM, ABS and BCM can cause problems with the TIPM.

TIPM is a fuse box, relay box and electronic module all in one. The electronic module is connected to several data networks.  For engineers, the module reduces a lot of wiring under the hood and passing through the firewall. The TIPM also increases the functionality of a component by allowing several inputs to control one component. 

Mercedes EQS Service Opportunities

EQ is the EV brand for Mercedes. It is the equivalent of Audi’s Etron or VW’s iD brands.

ADAS Calibration Tips

Here are 10 tips to follow during ADAS Calibration.

Chassis Control Modules After Reconnecting Battery

To resolve the issue, fully disconnect the negative lead from the battery terminal.

Reflashing Power Supplies

A power supply to keep the system voltage consistent is a required piece of equipment to perform a reflash procedure.

Other Posts

GM, Honda Begin Volume Production of Fuel Cell Systems

GM and Honda will produce fuel cells that will be two-thirds less expensive compared to Honda’s 2019 Clarity fuel cell.

BMW Transfer Case Service

The transfer case is a rather unique design in the way that it operates a clutch pack mechanically, not hydraulically.

Today’s Fuel Pressure Diagnostics

Direct injection pressure is measured with sensors, and you’ll need a scan tool to measure the signals

OBDII Connectors

OBDII connectors serve as the main communication point between the technician and the vehicle.