QLS Calibration - Everything You Need to Know

The commercial vehicle industry has experienced unprecedented supply shortages on some necessary components. One such component is the DEF Quality Level Sensor (QLS). Due to this shortage, the EPA and CARB worked together to help provide relief from the global supply shortage of electrical components. As supply has started to build back up, the process for handling these failures has changed.

As of 12/31/2022 the International QLS emergency calibration is no longer available. For all repairs performed after this date, dealers are directed to order the required parts. The calibration for the X15 and ISX product is set to expire on 1/13/2023.

Navistar has adequate inventory and supply to support a fix as fail repair strategy for the DEF head unit failures moving forward. Any vehicle that has received the calibration should NOT have the QLS replaced once parts are made available. All ehicles that have filed for the AFC and TRP will be put into a voluntary emission recall that will be released at a later date once the inventory levels in the PDCs and Dealer network are sufficient to support this activity. Navistar will provide additional communication for the part removal and calibration roll back on vehicles currently with the emergency calibration at a later date.

Frequently Asked Questions:

1. What does this mean for me and my truck? In summary, the trucks that have already been calibrated should continue as is and wait for the recall letter to be sent. For any trucks that experience a failure from 12/31/2022 or after, we will diagnose the problem and replace the part as needed.
   
   
2. Who pays for the calibration, fleet count and diagnostic time? For Cummins powered vehicles, only if the QLS emergency calibration is installed, it will be filed and paid through the TRP# T2489. For Navistar powered vehicles, only if the QLS emergency calibration is installed, it will be filed and paid through AFC #21901 (expired 12/31/2022).
   
   
3. If the TRP has already been completed prior to the release of the pigtail cutting procedure, should the vehicle be brought back in to have the harness cut? If the truck has not been released it should have the harness cut. If the truck has been released to service, it should not be taken out of service without a complaint.

For additional information on this calibration, please contact your local Thompson Truck & Trailer so our service team can walk you through next steps. Information about the original QLS calibration process can be found here.