2003 Saturn ION L4-2.2L VIN FFACTORY OEM SERVICE PROCEDURE

Ignition Control Module: Description and Operation



IGNITION CONTROL MODULE (ICM) AND IGNITION COILS

Ignition Control Module (ICM) And Ignition Coils:

Factory service manual diagram



Each ignition coil supplies secondary voltage to a pair of spark plugs. This is called a waste spark ignition system. The engine control module (ECM) supplies a signal on each of the ignition control (IC) timing control circuits to the ignition control module (ICM). The ICM fires the correct ignition coil at the correct time based on the signals. The ICM detects if cylinder 1 or cylinder 3 is on the compression stroke by sensing the secondary voltage and polarity of each side of the ignition coil. The higher voltage is on the compressing cylinder. This is called compression sense ignition. The ICM provides a synthesized cam signal to the ECM based on these inputs. The ECM uses the cam signal to synchronize fuel injection. This system consists of the following circuits:
- The ignition 1 voltage circuit
- The ground circuit
- The camshaft position (CMP) sensor signal circuit
- The IC timing control for cylinders #1 and #4
- The IC timing control B circuit for cylinders #2 and #3

Factory Service Tools

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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.