Engine Warm-Up Mode

THIS IS AN OPEN LOOP MODE.
During engine warm-up, the Powertrain Control Module (PCM) receives input from:
- Battery voltage

- Crankshaft position (CKP) sensor

- Engine coolant temperature (ECT) sensor

- Intake air temperature (IAT) sensor

- Manifold absolute pressure (MAP) sensor

- Throttle position sensor (TPS)

- Camshaft position (CMP) sensor

- A/C select switch (if equipped)

Based on these inputs the PCM will:
- Apply voltage to the injectors. The PCM then controls injection sequence and pulse width by switching individual injector ground paths on and off.

- Adjust engine idle speed through the IAC motor.

- Adjust ignition timing.

- Operate A/C Compressor Clutch relay (if equipped and selected).

- Operate the Up-Shift indicator light.

- Begin to monitor oxygen sensor. When engine is at operating temperature, the system will leave warm up mode and go into closed loop operation.