Applicable Systems
EMCP 4.2
Symptoms
Engine derate to 75% power. Exhaust temperature exceeds normal range.
Possible Causes
- Turbocharger wastegate stuck closed.
- Exhaust aftertreatment DPF partially clogged.
- Engine running rich due to faulty fuel injectors.
Troubleshooting Steps
- Step 1: Inspect turbocharger wastegate actuator rod for free movement.
Rod moves smoothly without binding; no carbon buildup. - Step 2: Check DPF differential pressure sensor reading at idle.
DPF delta pressure < 1.5 kPa at idle (clean). - Step 3: Perform cylinder cut-out test and compare exhaust temperatures.
All cylinders within 50°C of each other; no single high outlier.
How to Reset
Replace faulty turbocharger or DPF if delta pressure exceeds 10 kPa; reset engine derate via Cat ET.
Common Replacement Parts
- Turbocharger 359-4063: Turbocharger 359-4063
- DPF Filter 436-2926: DPF Filter 436-2926
Frequently Asked Questions
- Q: Can I clean a clogged DPF?
Yes, use Cat approved passive or active regeneration; replace if cracked.
- Q: What causes turbocharger wastegate to stick?
Carbon deposit buildup or broken actuator spring.
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Source: Caterpillar C15 Engine Service Manual
Category: Heavy Equipment
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