J.D. Power: Problems still dog emission-compliant diesels

The annual Heavy-Duty Truck Engine and Transmission Study conducted by research firm J.D. Power and Associates finds that technology changes related to the 2010 exhaust emission mandate are causing an increase in heavy-duty truck engine problems and a decrease in overall satisfaction with the powertrain.

This report follows the firm’s heavy-duty truck customer satisfaction study released in June, which also highlighted the toll engine issues are taking on overall customer satisfaction.

J.D. Power’s  2012 engine and transmission study – conducted between February and May this year and based on the responses of 1,725 primary maintainers of Class 8 heavy-duty trucks that are one model-year-old – measures satisfaction via eight key factors: engine reliability and dependability; engine warranty; acceleration when fully loaded; electronic control module; accessibility to components for service or maintenance; vibration at idle; maintaining speeds on grades; and average fuel economy.

The firm’s poll found that 46% of owners of heavy-duty trucks that are one model-year old report experiencing some type of engine-related problem, up from 42% in 2011. The most commonly reported engine problems are issues with the electronic control module calibration (23%), exhaust gas recirculation (EGR) valve (20%), and electronic engine sensors (16%).

In addition, the average number of engine- and fuel-related problems has increased to 81 problems per 100 vehicles (PP100) from 71 PP100 in 2011.  The rise in problems has impacted overall engine satisfaction, which declines to 719 index points on a 1,000-point scale in 2012, compared with 739 in 2011, noted Brent Gruber, director of the commercial vehicle practice at J.D. Power. 

“At the industry level, the new, more complex engines designed to meet EPA [Environmental Protection Agency] regulations are resulting in additional problems and downtime, which also has a financial impact on owners because they’re not making money when their truck is down for service,” he said.

However, Gruber adds that once manufacturers resolve quality issues related to the new technology, customers may expect to see some added benefits from the new engines. In the on-highway segment, the average reported engine service interval has increased to 22,703 miles in 2012, up from 20,303 in 2011.

Additionally, maintainers of heavy-duty on-highway trucks report a 4% increase in fuel efficiency this year, averaging 6.3 miles per gallon (mpg) in 2012, compared with 6 mpg in 2011.

“The new engines are proving to be more fuel efficient and allowing greater up-time between service so despite initial quality issues, the new technology may offer a greater return on investment in the long run,” said Gruber.

J.D. Power’s survey also discerned that truck engines build by Daimler AG’s Detroit subsidiary – formerly known as Detroit Diesel – rank highest in customer satisfaction with a score of 753, a 20-point improvement from 2011, and performs particularly well in the engine reliability and dependability factor. Cummins ranks second at 729 and Caterpillar third at 721.

Overall satisfaction with heavy-duty truck transmissions averages 812 in 2012, down eight points from 2011 – a decline Gruber noted is largely attributed to lower satisfaction with the reliability and dependability of the transmission and drivetrain. This decline in satisfaction comes despite transmission-related quality actually improving to 7 PP100 in 2012, down from 10 PP100 in 2011.