SPN 612 - FMI 2 (Fault Code 115)

SPN 612 - FMI 2 (Fault Code: 115)

ISB, ISC, ISL with CM2150 - Engine Magnetic Speed/Position

Fault Code: 115
PID(P), SID(S): P190
SPN: 612
FMI: 2/2
Lamp: RED

REASON: Engine Magnetic Speed/Position Lost Both of Two Signals - Data Erratic, Intermittent, or Incorrect. The engine control module (ECM) has detected that the primary and backup speed sensor signals are connected backwards.

EFFECT: The engine will shut down or will NOT start/ running.

Circuit Description:
The crankshaft position and camshaft position sensors are Hall effect type sensors. The ECM provides a 5 volt supply to the position sensor and a return circuit. As the teeth on the crankshaft speed ring or the dimples in the back of the camshaft gear move past the position sensor, a signal is generated on the position sensor signal circuit. The ECM interprets this signal and converts it to an engine speed. A missing tooth on the crankshaft gear is used by the ECM to determine the position of the engine.

Component Location:
Both engine position sensors are located on the back side of the front gear housing above the fuel pump drive.

Conditions for Running the Diagnostics:
This diagnostic runs continuously when the engine is running.

Conditions for Setting the Fault Codes:
The ECM detects that the crankshaft position and camshaft position signal inputs to the ECM are reversed.

Action Taken When the Fault Code is Active:
• The ECM illuminates the red STOP ENGINE light immediately when the diagnostic runs and fails.
• The ECM detects the reversed sensors and continues to operate.

Conditions for Clearing the Fault Code:
The ECM will turn off the red STOP ENGINE light immediately after the diagnostic runs and passes.

Shop Talk:

  • Verify the ECM calibration is correct. Check the calibration revision history found on QuickServe® Online for applicable fixes to the calibration stored in the ECM. If necessary, calibrate the ECM. 
  • This fault code indicates that the camshaft position sensor and crankshaft position sensor wiring harness connectors are reversed.

Read More:
SPN 629 - FMI 12 (Fault Code 111)
SPN 102 - FMI 3 (Fault Code 122)


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2 Responses to "SPN 612 - FMI 2 (Fault Code 115)"

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  2. Kw t680, I was backing into dock , and pulled forward and now it won't come out of low gear and sensor went off ...can't seem to get it out of gear ...clutch isnt responding