Practice question
On a school bus diesel with selective catalytic reduction (SCR), low or contaminated diesel exhaust fluid (DEF) will MOST likely cause:
- Improved NOx control and more power
- Lower coolant temperature
- High NOx emissions, fault codes, and an engine power derate
- Higher oil pressure
Answer: C — High NOx emissions, fault codes, and an engine power derate
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Practice more: ASE S2 Diesel Engines (School Bus) Practice Questions - ASE S2 - Diesel Engines (School Bus) Certification Exam →