Cylinder Identification Sensor: Description and Operation

NOTE:
This engine may be equipped with either Sequential Fuel Injection (SFI) or Multiport Fuel Injection (MFI). For easy distinction SFI engines use a a Mass Air Flow (MAF) sensor while MFI vehicles are equipped with a Manifold Absolute Pressure (MAP) sensor.



PURPOSE
In a MFI system the fuel injectors are fired in two separate banks. A hall effect sensor is used to identify when number 1 cylinder is on compression stroke. This information allows the Powertrain Control Module (PCM) to sequence the fuel injector banks in the correct order.

In a SFI system each individual fuel injector is energized just prior to the opening of its corresponding intake valve. A hall effect sensor is used to identify when number 1 cylinder is on compression stroke. This information allows the PCM to sequence the fuel injectors in the correct order.

In the MFI and SFI systems the Camshaft Position (CMP) sensor provides both the Cylinder Identification (CID) signal and the ignition reference signal.

CONSTRUCTION
The sensor is a single hall effect magnetic switch, activated by a 8 vane rotor which is driven by the camshaft. The CMP is located within the distributor and can be serviced separately.

Computer Controlled Dwell ICM Waveforms:

OPERATION
The camshaft drives the hall effect rotor. On the rotor there are 8 shutters, each one corresponding to a specific cylinder. The shutter corresponding to number 1 cylinder has a narrower width than the others. This produces a signature Profile Ignition Pickup (PIP) signal, which allows the PCM to distinguish number 1 cylinder from the rest. The signature PIP signal is processed by the Ignition Control Module (ICM) prior to being sent to the PCM.

RELATED DIAGNOSTIC TROUBLE CODES

DTC 214 - Cylinder Identification (CID) circuit failure.