 Let's help you next. Get started today. Call 1-800-217-4380. That's 1-800-217-4380. Again, 1-800-217-4380. Time is money. When the check engine light comes on with reduced power, that could mean that your engine is in D-rate, protecting itself from damage until repaired. If this happens in the Portland area, call Ultimate Truck Service first. They keep diesel trucks and pushers road ready. Experts at solving emission issues.