Applicable Systems
EMCP 4.2
Symptoms
Engine loses power under load; fuel pressure reading below specification; possible stalling at high RPM.
Possible Causes
- Fuel filter element clogged/restricted
- Fuel transfer pump worn or damaged
- Fuel supply line restriction or leak
Troubleshooting Steps
- Step 1: Check fuel filter service hours (replace at 500hr)
Filter within service interval - Step 2: Measure fuel delivery pressure at filter outlet
Pressure >= 35 psi at rated RPM - Step 3: Replace both primary and secondary fuel filters
New filters installed and primed - Step 4: Test fuel transfer pump output
Pump output >= 45 psi at 1500 RPM - Step 5: Clear code with Cat ET and load test engine
No power loss, fuel pressure nominal
How to Reset
Clear SPN codes via Cat ET J1939 code reader.
Common Replacement Parts
- Fuel Filter Primary P/N: 1R-0741
- Fuel Transfer Pump P/N: 10R-0450
Frequently Asked Questions
- Q: What causes low fuel pressure on Cat C9?
Most commonly clogged fuel filters, followed by transfer pump wear. Always replace filters first.
Source: verizonconnect.com DTC guide
Category: Heavy Equipment