Fuel Pump Pressurizing Actuator #1 Mechanical System Not Responding
The CUMMINS-273 (Cummins) diesel fault code means: Fuel Pump Pressurizing Actuator #1 Mechanical System Not Responding. This is a critical severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- advanced
- Estimated cost
- $800-$2,500
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Common Symptoms
- Engine protect mode or forced shutdown
- Hard starting or extended cranking
- Power loss under load
- Rough idle and stalling
- Black smoke or white smoke at exhaust
- Poor fuel economy
Probable Causes (Ranked by Likelihood)
- Failed high-pressure fuel pump (CP3 or CP4) Likely
- Clogged fuel filters (primary or secondary) Very Likely
- Failed or stuck fuel rail pressure regulator Likely
- Leaking or stuck injector Possible
- Weak lift pump causing low supply pressure Possible
- Wiring or harness damage at injector or rail Less Likely
Frequently Asked Questions
What is Cummins fault code 273?
Cummins fault code 273 indicates: Fuel Pump Pressurizing Actuator #1 Mechanical System Not Responding. It is a critical-severity fault in the fuel delivery system.
Can I drive with Cummins fault code 273?
Yes, short-term driving is typically safe with fault 273, but the fault will illuminate the Check Engine Light and must be diagnosed soon. Monitor for power loss, unusual noises, or gauge changes and pull over if conditions worsen.
How much does it cost to fix Cummins fault 273?
Repair cost is approximately $800-$2,500 including parts, labor, and any dealer programming required. DIY repairs (sensor replacement) fall at the low end; pump, aftertreatment, or ECM work falls at the high end and usually requires INSITE diagnostic software.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
Connect INSITE, command injector cutout test, and observe RPM drop per cylinder to localize injector faults.
Verify fuel rail pressure on INSITE matches commanded pressure (within 10%) at idle and under load.
Inspect both fuel filters (primary/water separator and secondary) for restriction -- replace if overdue.
Check lift pump supply pressure at inlet to CP3/CP4 high-pressure pump (spec varies, typically 5-10 psi).
Inspect fuel return line flow per injector using a return-line test kit to spot a leaking injector.
Check fuel for water contamination and microbial growth -- drain water separator before starting.
If high-pressure pump is suspect, perform a pump low pressure test; replace pump and contaminated fuel if failed.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
- SAE J1939-73Application Layer: Diagnostics (defines the SPN/FMI fault-identifier framework)
Commonly Affected Vehicles
- Peterbilt 579, 567 with Cummins ISX/X15
- Kenworth T680, T880 with Cummins X15
- Ram 2500/3500 with 6.7L Cummins
- Ram 4500/5500 with 6.7L Cummins
- Freightliner M2 106 with Cummins ISL9/L9
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