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.
Circuits Affecting Ignition Control
In order to properly control the ignition timing, the PCM relies on the following information:
- The engine load, based on the manifold pressure or vacuum
- The atmospheric or barometric pressure (BARO)
- The engine temperature
- The intake air temperature (IAT)
- The crankshaft position
- The engine speed (RPM)
The ignition control (IC) system consists of the following components:
- The ignition coils
- The 24X crankshaft position (CKP) sensor
- The powertrain control module (PCM)
- All connecting wires
The ignition control uses the following signals and circuits in order to control the spark timing functions:
- The 24X signal-The 24X crankshaft position sensor sends a signal to the PCM. The PCM uses this signal in order to determine the crankshaft position. The PCM also utilizes this signal in order to trigger the fuel injectors.
- The ignition control (IC) circuits-The PCM uses these circuits in order to trigger the ignition coils.
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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.