SPN 636 — Engine Position Sensor (Camshaft)
System: Engine
Camshaft position signal used for injection timing and cylinder identification.
Can I keep running it?
HIGH — limit use, diagnose now
May cause hard starting, rough running or no-start.
Likely causes
- Faulty cam sensor
- Wrong air gap or debris on the sensor
- Damaged tone ring
- Wiring fault
Checks & fixes (easiest first)
- Inspect the sensor tip for metal debris
- Check resistance and wiring
- Compare cam and crank signals with a scope
- Check for SPN 637 together
Common FMIs with SPN 636
- SPN 636 FMI 2Data erratic, intermittent, or incorrect
- SPN 636 FMI 5Current below normal or open circuit
- SPN 636 FMI 8Abnormal frequency, pulse width, or period
- SPN 636 FMI 10Abnormal rate of change
Related codes
FAQ
What does SPN 636 mean?
SPN 636 is Engine Position Sensor (Camshaft). Camshaft position signal used for injection timing and cylinder identification.
Can I keep running with SPN 636?
May cause hard starting, rough running or no-start.
What causes SPN 636?
Faulty cam sensor; Wrong air gap or debris on the sensor; Damaged tone ring; Wiring fault.