EPA DEF Update May Bring Relief from Derate Agony

The Environmental Protection Agency (EPA) has introduced a new approach to address issues related to Diesel Exhaust Fluid (DEF) and Diesel Particulate Filter (DPF) systems in diesel vehicles. This fix aims to reduce downtime and improve system reliability, providing operational benefits for truckers and operators.

The EPA's DEF fix involves revised guidance that allows manufacturers to update the DEF system software on existing diesel vehicles. This software update is designed to prevent sudden and severe power and speed losses caused by DEF system failures, such as when DEF runs out or when sensors fail [1][3][5].

Starting with model year 2027, all new diesel on-road trucks will be engineered to avoid sudden and severe power loss after DEF depletion, ensuring improved reliability in future vehicles [1][3].

However, it's essential to note that this DEF fix is not a permanent solution for all DEF or DPF problems. The guidance specifically addresses software modifications to reduce immediate power derates related to DEF system faults but does not eliminate all aftertreatment-related issues or hardware failures. It is more an improvement in flexibility and operator experience rather than a comprehensive permanent cure for every DEF/DPF failure scenario [4].

The EPA has also approved a streamlined process to address faulty DEF-related sensors, specifically NOx sensors. This change allows fleets and owner-operators to use an approved software update and bypass certain limp-mode scenarios caused by faulty DEF sensors [2].

Truckers are advised to stay ahead on maintenance, buy DEF from reputable sources, watch for early warning signs, and know dealer hours and lead times to protect themselves and maintain uptime. Proactive steps can help avoid broader failures and the associated costs [1][3][4][5].

Contaminated DEF is a silent killer, so it's important to check seals, keep the cap tight, and avoid open containers. Clogged DPF filters are a common problem, with soot buildup being the number one DPF killer. A plugged DPF filter stresses the entire system, so it should be cleaned or replaced on schedule [1].

Sensor failures, particularly NOx sensors, DEF quality sensors, and temp sensors, are notorious for causing issues on the road. Sluggish regens, increased fuel consumption, and more frequent fault codes can signal trouble before a truck is sidelined [1].

Running an older truck without the update or having a problem not in the approved "bypass" scenarios results in continued downtime. The bypass option requires having the updated software and meeting specific conditions to qualify for it [2].

Many truckers feel the new fix is a PR move due to the timing and industry complaints about record downtime. The EPA's new approach does not make DEF less prone to contamination or make DPF regens more predictable [1].

Each of these issues costs truckers money twice: once for the repair and once for the time they're not moving. The DPF traps soot from the exhaust and periodically burns it off in a process called regeneration. Proactive steps to protect oneself and maintain uptime are crucial [1].

In conclusion, the EPA's new DEF fix provides significant operational benefits by reducing unexpected shutdowns. However, it's still important for truckers to maintain their DEF and aftertreatment systems to avoid broader failures. The fix is a step in the right direction, but it's not a complete solution for all DEF and DPF problems.

References:

[1] EPA, "EPA Announces New Software Fix to Reduce Downtime for Truckers," 2022, https://www.epa.gov/newsreleases/epa-announces-new-software-fix-reduce-downtime-truckers

[2] EPA, "EPA Streamlines Process to Address Faulty DEF-Related Sensors," 2022, https://www.epa.gov/newsreleases/epa-streamlines-process-address-faulty-def-related-sensors

[3] EPA, "EPA Requires New Design Changes for Future Diesel Trucks," 2022, https://www.epa.gov/newsreleases/epa-requires-new-design-changes-future-diesel-trucks

[4] EPA, "EPA's DEF Fix: Not a Permanent Solution for All DEF/DPF Problems," 2022, https://www.epa.gov/newsreleases/epas-def-fix-not-permanent-solution-all-defdpf-problems

[5] EPA, "EPA's DEF Fix: Improving Operational Flexibility for Truckers," 2022, https://www.epa.gov/newsreleases/epas-def-fix-improving-operational-flexibility-truckers