Engine Magnetic Speed/Position Lost Both of Two Signals
The CUMMINS-115 (Cummins) diesel fault code means: Engine Magnetic Speed/Position Lost Both of Two Signals. This is a critical severity code.
- Keep driving?
- No — stop driving
- DIY difficulty
- advanced
- Estimated cost
- $400-$900
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View pilot availability →What Are the Symptoms of CUMMINS-115?
- Engine protect mode or forced shutdown
- Check Engine Light illuminated
- Engine may shut down or fail to start
- Erratic engine behavior or warning messages on dash
- Loss of communication with scan tool
- Engine derate or limp mode
What Causes CUMMINS-115? (Most Likely First)
- Internal ECM processor or memory fault Very Likely
- ECM software corruption requiring reflash Likely
- Low battery voltage during ECM power-up Possible
- Damaged ECM connector or harness pins Possible
- Ground fault at ECM mounting location Less Likely
Can I Still Drive with CUMMINS-115?
No — stop driving. CUMMINS-115 is rated critical severity. Continuing to drive in this state risks further damage — get it looked at before your next trip.
Frequently Asked Questions
What is Cummins fault code 115?
Cummins fault code 115 indicates: Engine Magnetic Speed/Position Lost Both of Two Signals. It is a critical-severity fault in the engine control module or its circuits.
Can I drive with Cummins fault code 115?
No. Fault code 115 triggers protective engine shutdown or severe derate. Continued operation risks engine damage or stranding. Tow to a Cummins dealer or qualified diesel shop.
How much does it cost to fix Cummins fault 115?
Repair cost is approximately $400-$900 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
How Do You Diagnose CUMMINS-115?
Connect Cummins INSITE or Nexiq USB-Link and confirm fault code 115 (SPN 612 FMI 2) is active, not historical.
Measure ECM battery supply voltage at pins - must read battery voltage key-on and stable during cranking (no drops below 9V).
Inspect ECM grounds at frame and engine block for clean, tight connections with no paint or corrosion.
Check for available Cummins calibration updates via INSITE. Reflash if an update addresses this fault.
Perform ECM output driver and internal test via INSITE. If it fails, ECM replacement and dealer programming is the fix.
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)
Which Vehicles Commonly Get CUMMINS-115?
- 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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