EGR Valve Position - Data Erratic
The CUMMINS-2749 (Cummins) diesel fault code means: EGR Valve Position - Data Erratic. This is a moderate severity code.
- Keep driving?
- Reduced power (derate)
- DIY difficulty
- advanced
- Estimated cost
- $400-$1,500
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Common Symptoms
- Power loss especially under load
- Turbo lag or sluggish acceleration
- Black smoke under acceleration
- Higher than normal EGT
- Check Engine Light on
Probable Causes (Ranked by Likelihood)
- EGR valve carbon-seized in partially open position Very Likely
- Failed EGR position sensor Likely
- Clogged EGR cooler restricting flow Likely
- VGT actuator stuck from carbon or corrosion Possible
- Leaking EGR cooler causing coolant loss Possible
Frequently Asked Questions
What is Cummins fault code 2749?
Cummins fault code 2749 indicates: EGR Valve Position - Data Erratic. It is a moderate-severity fault in the aftertreatment or emissions system.
Can I drive with Cummins fault code 2749?
Short-term, yes, but the engine will enter derate (typically starting at 55 mph and progressing to 5 mph for emissions faults). Drive directly to a repair facility. Do not defer this fault more than a few operating hours.
How much does it cost to fix Cummins fault 2749?
Repair cost is approximately $400-$1,500 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.
What actually makes the computer set this EGR code?
California's heavy-duty OBD regulation sets the low-flow trip point where a decrease from the manufacturer's specified EGR rate would push NMHC, CO or NOx past 2.0 times the applicable standards, or PM past the standard plus 0.02 g/bhp-hr (Title 13 CCR 1971.1, section (e)(3.2.1)). Note the second route: it must also flag the case where the EGR system has hit its control limits and simply cannot reach the commanded flow — so this code can set with the valve working and the system still unable to deliver. This threshold comes from the heavy-duty OBD regulation, which covers 2010 and later heavy-duty engines. If your engine is in a pickup at or under 14,000 lb GVWR it is certified under the separate medium-duty rule instead, so treat this as the design intent rather than your engine's exact limit.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
Connect INSITE and command the EGR valve through its full range while monitoring position feedback for smooth response.
Remove EGR valve and inspect for carbon buildup; soak in carbon cleaner and reinstall or replace if deeply fouled.
Measure VGT actuator voltage and calibration via INSITE output test -- command 0%/50%/100% and verify position.
Inspect EGR cooler for internal leakage (coolant loss or steam from exhaust) -- pressure test if suspect.
Check turbocharger for shaft play, oil leaks at seals, and smooth spool under throttle.
Verify EGR differential pressure and temperature sensors read rational values on INSITE data list.
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- California Code of Regulations, Title 13 section 1971.1 (Heavy-Duty OBD)malfunction criteria, section (e)
- 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
- Freightliner Cascadia with Cummins ISX15
- Ram 2500/3500 with 6.7L Cummins
- Freightliner M2 106 with Cummins ISL9/L9
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