Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

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Electronic Ignition (EI) System

POWERTRAIN CONTROL MODULE (PCM)

The PCM controls all ignition system functions, and constantly corrects the basic spark timing. The PCM monitors information from various sensor inputs that include the following:
- The throttle position (TP) sensor
- The engine coolant temperature (ECT) sensor
- The mass airflow (MAF) sensor
- The intake air temperature (IAT) sensor
- The vehicle speed sensor (VSS)
- The transmission gear position or range information sensors
- The engine knock sensors (KS)