Engine Magnetic Speed/Position Lost Both of Two Signals
What does CUMMINS-115 mean?
The CUMMINS-115 (Cummins) diesel fault code means: Engine Magnetic Speed/Position Lost Both of Two Signals. This is a critical severity code.
Common Symptoms
- 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
Probable Causes (Ranked by Likelihood)
- 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
Step-by-Step Diagnostic Procedure
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.
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.