Circuit/System Verification

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

Ignition - On / Vehicle - In Service Mode
Verify there are no DTCs set related to the following system/component:
- B34 Engine Coolant Temperature Sensor
- B52 Heated Oxygen Sensor
- B66 Intake Air Temperature Sensor
- B74 Manifold Absolute Pressure Sensor
- B75C Multifunction Intake Air Sensor
- Q17 Fuel Injector
- Q38 Throttle Body
- Engine Misfire
- Fuel Trim System
- If a related DTC is set
  Refer to: Diagnostic Trouble Code (DTC) List - Vehicle
- Go to next step: If a related DTC is not set
Verify the following conditions do not exist:
- Coolant consumption - Refer to: Loss of Coolant
- Oil consumption - Refer to: Oil Consumption Diagnosis
- If a condition exists
  Repair or replace as necessary.
- Go to next step: If no condition exists
Verify a condition does not exist with the component: B52 Heated Oxygen Sensor - Loose/Poor Connection/Visible Damage
- If a condition exists
  Repair or replace as necessary.
- Go to next step: If no condition exists
Verify a condition does not exist with the component: Exhaust System & Three-Way Catalytic Converter
- Cracked
- Internal component rattle
- Leaking - Refer to: Exhaust Leakage
- Loose Clamps
- Missing components
- Restrictions - Refer to: Restricted Exhaust
- Severe discoloration caused by excessive temperatures
- Visible Damage
- If a condition exists
  Repair or replace as necessary.
- Go to next step: If no condition exists
Test or replace the component: Three-Way Catalytic Converter