The California Air Resources Board has moved to force owners of nearly 58,000 heavy-duty trucks built between 1993 and 1999 to upgrade onboard software to reduce smog-forming emissions.

In a press release issued Friday, the board said the action was taken after a seven-month trial voluntary program failed. The decision applies to an estimated 300,000 to 400,000 vehicles licensed in other states that drive through California.
Board chairman Dr. Alan Lloyd said, “These vehicles have been operating on California’s streets and roads for more than 10 years without any appreciable effort being made to replace their defective software and reduce their emissions. In March, we gave the manufacturers six months to upgrade a reasonable number of these trucks to avoid regulation, but we have not seen enough progress to wait longer and put Californians at further risk, therefore we must enact the regulation without further delay.”
Lloyd was appointed to the Air Resources Board in August by California Gov. Arnold Schwarzenegger.
The Associated Press reported that the action is the latest round in a battle regulators thought they had won more than six years ago with a $1 billion settlement with truck manufacturers. That the settlement required manufacturers to upgrade digital code, but only when engines underwent major overhauls -- something that happens less frequently than regulators expected.
The news agency also reported that the Engine Manufacturers Assn. has suggested it will sue on behalf of members who believe they shouldn't have to pay for diesel engine upgrades as required by the ruling.
The regulation, adopted in March 2004 will require most heavy-duty diesel trucks, buses and motor homes built between 1993 and 1999 to install new software, a process called reflash, to prevent the release of additional nitrogen oxide emissions. The Air Resources Board adopted the regulation after data showed that only about 13% of heavy-duty diesel vehicles that need reflash have been upgraded.
The mandatory program will require the oldest trucks -- 1993-94 models -- to be upgraded by April 30, 2005. Those built in model years 1995-96 must have their upgrades completed by Aug. 31, 2005 and those built in 1997 and 1998 must be reflashed by Dec. 31, 2005. Owners of 1997 and 1998 medium heavy-duty vehicles, mainly delivery trucks and motor homes, have until Dec. 31, 2006 to have the reflash completed.