Code 12, No Rpm Signal: Notes

PCM monitors crank angle and camshaft positions, and supplies .7 volt to crank angle and Camshaft Position (CMP) sensors. As signal rotor rotates, voltage is toggled high and low. PCM determines crank angle and camshaft positions by toggled voltage input.

Code 12 will set if PCM does not detect crank angle input while engine is cranking for 2 seconds or more, or PCM does not detect camshaft position input with engine speed 600-4000 RPM for 3 seconds or more.

1. Checks for faults in crank angle input low circuitry and PCM.
2. Checks for faults in crank angle input high circuitry and PCM.
3. Checks for faults in camshaft position input low circuitry and PCM.
4. Checks for faults in camshaft position input high circuitry and PCM. Also for a misadjusted signal rotor air gap.