QSM11 Fault Code
Free · no signupCode 115 / 121
Engine won't start.
System
Crank/Cam Sensors
Symptom
Engine won't start.
Diagnosis & fix steps
LOGIC: Loss of engine position signal.
ACTION: Check the CPS (Crank Position Sensor) located behind the air compressor.
Red Seal field insights
Pro-Tip: The QSM11 uses a "dual" sensor setup. If it starts but runs rough, one sensor is failing. If it won't start at all, check the harness near the starter—it often rubs through there.
Same code keeps coming back?
That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.
Read before you touch anything
- This is general reference information, not a repair manual. It is for trained, qualified technicians.
- Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
- Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
- You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
- Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.
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