This bulletin applies to 2019 Chevy Colorado trucks equipped with a 2.8L turbo diesel engine. Some customers may comment that the MIL is illuminated. They may also note that a “Service Emission System” message is displayed in the driver information center.
The technician may find DTC P206D (reductant quality sensor circuit high voltage) set in the K20 engine control module.
P206D can be falsely set by a concentration of reductant crystals around the sensor that forms when reductant freezes and thaws.
1. Verify that the reductant quality sensor is OK or ready.
2. Verify that the measured reductant concentration is greater than 28% and less than 40%.
3. Verify that the reductant tank temperature is greater than 41 degrees Fahrenheit (5 degrees Celsius).
If any of the above conditions are not met, ensure that the vehicle is parked indoors to allow the system to warm up to greater than 41 degrees F. Once warmed up, operate the vehicle in stop and go driving conditions for greater than 10 minutes. If the DTC P206D resets during or after driving, refer to the DTC flow chart in the service manual.