29 March 2004

The California Air Resources Board (ARB) reached an agreement with diesel engine manufacturers and adopted a voluntary “chip reflash” program. The voluntary plan requires manufacturers to upgrade the engine control software in affected MY 1993-1999 heavy-duty truck engines free of charge, according to the following schedule: 35% by November 2004; 60% by June 2005; 80% by February 2006; and 100% by 2008.

The program affects only California-licensed vehicles, the number of which is estimated at about 60,000. An estimated 300,000-400,000 out-of-state vehicles that drive through California are not affected, but must still comply with the EPA consent decree provisions.

California was considering a mandatory diesel “chip reflash” program, but it was concluded that the voluntary approach will result in upgrading the software more quickly than through a regulation.

Most of 1993-1999 MY engines (estimated 1.3 million engines in the US market) were equipped with software that switched to a more fuel efficient but higher NOx engine calibration (advanced injection timing) during steady-state highway cruising. These higher NOx emissions did not occur during emission certification testing, which is based on a transient test. This engine control strategy was deemed by the EPA and the ARB to be an illegal “emissions defeat device”. In 1998, under consent decrees signed with the DOJ/EPA, manufacturers agreed to develop a low NOx software upgrade. This revised software is now available through engine dealerships. However, the consent decrees require software upgrade only when the affected engines undergo major overhauls. Furthermore, heavy-duty vehicle operators have no incentive to do the “chip reflash”, as doing so results in deterioration of fuel economy. As a result, the progress of the software upgrade has been rather slow. The ARB estimates that the low NOx software has been installed on less than 10% of the affected engine population.

The ARB and trucking industry will launch a promotion program to encourage truckers to have the software upgraded. This outreach/promotion will be conducted in cooperation with the California Trucking Association and manufacturers: Caterpillar, Cummins, Diesel Detroit, Mack-Renault, Navistar and Volvo.

ARB news release

Source: California ARB