Breeze, Cirrus, Sebring Convertible and Sedan, Stratus Sedan, 1999-2005

Crankshaft & Camshaft Position Sensors

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Description & Operation



The Crankshaft Position (CKP) and Camshaft Position (CMP) sensors used with this EI system provide engine position and speed data to the powertrain control module (PCM). Both sensors are Hall effect devices. The CKP sensor is mounted on the transaxle, adjacent to a trigger wheel on the torque converter drive plate. The CMP sensor is mounted to the Bank 2 cylinder head, adjacent to a trigger wheel on the cam gear.

Both trigger wheels have slots that the Hall effect circuit senses and then toggles a transistor. The transistors send 5v pulses to the PCM that represents the position and duration of the trigger wheel slot.

The signal to the PCM will remain high as long as the Hall effect circuitry senses the slot in the trigger wheel. The PCM uses the pulsewidth from the CKP sensor to calculate engine speed. The Misfire Monitor also watches the pulsewidth to determine if crankshaft velocity has decreased more than allowed.

Click image to see an enlarged view

Fig.



Click image to see an enlarged view

Fig.

The Crankshaft Position (CKP) and Camshaft Position (CMP) sensors used with this EI system provide engine position and speed data to the powertrain control module (PCM). Both sensors are Hall effect devices. The CKP sensor is mounted on the transaxle, adjacent to a trigger wheel on the torque converter drive plate. The CMP sensor is mounted to the Bank 2 cylinder head, adjacent to a trigger wheel on the cam gear.

Both trigger wheels have slots that the Hall effect circuit senses and then toggles a transistor. The transistors send 5v pulses to the PCM that represents the position and duration of the trigger wheel slot.

The signal to the PCM will remain high as long as the Hall effect circuitry senses the slot in the trigger wheel. The PCM uses the pulsewidth from the CKP sensor to calculate engine speed. The Misfire Monitor also watches the pulsewidth to determine if crankshaft velocity has decreased more than allowed.

Click image to see an enlarged view

Fig.



Click image to see an enlarged view

Fig.

CKP & CMP Sensor Circuits

The CKP and CMP sensors are both connected to the PCM by 3 wires. The sensors share an 8v reference voltage from PCM Pin 2-44. They also share the sensor ground with most other engine sensors (PCM Pin 2-43). The 0-5 volt return signal is sent to PCM Pin 1-32. The CMP 0-5 volt return signal is sent to PCM Pin 1-33.

The CKP and CMP sensors are both connected to the PCM by 3 wires. The sensors share an 8v reference voltage from PCM Pin 2-44. They also share the sensor ground with most other engine sensors (PCM Pin 2-43). The 0-5 volt return signal is sent to PCM Pin 1-32. The CMP 0-5 volt return signal is sent to PCM Pin 1-33.

Sensor Signal Relationships

The CMP trigger wheel contains slots grouped in the following order: 1, 2, 3, 1, 3, and 2. Since each number is repeated, the PCM must keep track of the sequence over time in order to properly calculate cylinder position. Also, these pulses do not occur at TDC. They only signal the PCM which cylinder will be arriving at TDC next. The PCM then uses CKP sensor pulses to count down to TDC for the designated cylinder.

There are 13 slots in a ring on the CKP trigger wheel (in two groups of 4 and one group of 5 slots). The PCM determines engine position at the falling edge of the fourth pulse in each group. The slots are located at 69, 49, 29, and 9 before TDC for whichever pair of cylinders is approaching TDC. After the CMP pulse designates which cylinder is expected to arrive at TDC next, the falling edge of the fourth CKP pulse designates 9 before TDC.

The extra (thirteenth) slot occurs 11 after TDC, and helps the PCM to determine engine position at startup without having to wait for the complete CMP pulse sequence.

The CMP trigger wheel contains slots grouped in the following order: 1, 2, 3, 1, 3, and 2. Since each number is repeated, the PCM must keep track of the sequence over time in order to properly calculate cylinder position. Also, these pulses do not occur at TDC. They only signal the PCM which cylinder will be arriving at TDC next. The PCM then uses CKP sensor pulses to count down to TDC for the designated cylinder.

There are 13 slots in a ring on the CKP trigger wheel (in two groups of 4 and one group of 5 slots). The PCM determines engine position at the falling edge of the fourth pulse in each group. The slots are located at 69, 49, 29, and 9 before TDC for whichever pair of cylinders is approaching TDC. After the CMP pulse designates which cylinder is expected to arrive at TDC next, the falling edge of the fourth CKP pulse designates 9 before TDC.

The extra (thirteenth) slot occurs 11 after TDC, and helps the PCM to determine engine position at startup without having to wait for the complete CMP pulse sequence.

 
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