The Cylinder Position (CYP) sensor is a critical component for determining engine phase and enabling sequential ignition timing. The sensor operates as a magnetic pickup, generating a pulse when a ferrous target passes the sensor coil.

Sensor Location and Configuration#

The physical location of the CYP sensor varies based on the engine architecture:

• SOHC Engines: The CYP sensor is integrated within the distributor housing.
• DOHC Engines: The CYP sensor is mounted externally at the end of the exhaust camshaft.

Note

On the 1991 CRX, the CYP sensor is a two-wire magnetic sensor located at the front of the distributor assembly.

Functional Role#

The ECU utilizes the signal from the CYP sensor to establish the engine's firing order. Upon receiving the CYP signal, the ECU initiates the sequential ignition sequence (1-3-4-2).

Important

If the CYP sensor signal is lost or erratic, the ECU will trigger the Malfunction Indicator Lamp (MIL). Symptoms of a faulty sensor or signal interference include engine pinging, misfires, and improper ignition timing.

Diagnostic Considerations#

• Signal Interpretation: Excessive ignition advance or retard does not necessarily indicate a faulty CYP sensor; verify sensor output before assuming component failure.
• Signal Integrity: Ensure the sensor wiring is free from electromagnetic interference, as the low-voltage magnetic pulse is sensitive to electrical noise.

Cylinder Position (CYP) sensor assembly