Diagnostic Aids

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.

{ If equipped }Command the Cylinder Deactivation system On with a scan tool, then observe the misfire counters when commanding the system Off. If the misfire counters are incrementing, inspect for a sticking valve lifter.
DTC P0300 may set when there is a condition with the component circuits: B52 Heated Oxygen Sensor
High resistance in the circuits of the component may set DTC P0300 - P0308 without setting the DTC for the component: Q17 Fuel Injector
If the condition is intermittent, wiggle the related wiring harnesses and connectors, with the ignition/vehicle on or engine running, while monitoring the scan tool circuit status parameters for the component. The parameters will display if there is a condition with the circuit or a connection.
Verify the following conditions do not exist:
- Accessory drive bracket - Defective/Loose/Visible Damage
- Belt Driven Device - Defective/Loose/Visible Damage
- Brake Rotor - Excessive runout
- Drive Belt - Defective/Loose/Visible Damage
- Drive Shaft - Excessive runout
- During certain road conditions: Rough
- Tire and wheel assemblies which exhibit excessive runout can produce vibrations even if the assemblies are balanced.
- Transmission - Incorrect Operation