Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit Description
3X reference circuit is produced by Ignition Control Module (ICM). PCM uses 3X reference signal pulses to calculate engine speed (RPM) and crankshaft position at engine speed more than 1200 RPM. PCM uses pulses on this circuit to initiate injector pulses. If PCM receives incorrect number of pulses on 3X reference circuit, DTC P1374 will set.
Conditions required to set DTC are:
- Engine running and PCM is receiving 18X reference signal pulses.
- Ratio of 18X reference signal pulses to 3X reference signal pulses received by PCM do not equal 6.
- Ratio of 18X reference signal pulses to camshaft reference signal pulses received by PCM equals 36.
- Conditions present for up to 30 seconds or 100 crankshaft revolutions.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.