Powertrain Control Module Sensors/Switches
INFORMATION SENSORS/SWITCHES DESCRIPTION3X REFERENCE PCM INPUT
From the ignition control module, the PCM uses this signal to calculate engine RPM and crankshaft position at engine speeds above 1700 RPM. The PCM also uses the pulses on this circuit to initiate injector pulses. If the PCM receives no pulses on this circuit, DTC P1374 will set and the PCM will use the 18X reference signal circuit for fuel and ignition control. The engine will continue to start and run using the 18X reference signal only. Refer to Electronic Ignition System for further information.
18X REFERENCE PCM INPUT
From the ignition control module, the PCM uses this signal to calculate engine RPM and crankshaft position at engine speeds below 1200 RPM. The PCM also uses the pulses on this circuit to initiate injector pulses. If the PCM receives no pulses on this circuit, DTC P0376 will set and the PCM will use the 3X reference signal circuit at all times for fuel and ignition control. The engine will continue to start and run using the 3X reference signal only. Refer to Electronic Ignition System for further information.
A/C REFRIGERANT PRESSURE SENSOR
The A/C refrigerant pressure sensor signal indicates high side refrigerant pressure to the PCM. The PCM uses this information to adjust the idle air control valve to compensate for the higher engine loads present with high A/C refrigerant pressures and to control the cooling fans. A fault in the A/C refrigerant pressure sensor signal will cause DTC P0530 to set. Refer to Heater, Ventilation, and Air Conditioning for a complete description and on-vehicle service.
A/C REQUEST PCM INPUT
The A/C request signal indicates to the PCM that an A/C mode is selected at the A/C control head. The PCM uses this information to adjust the idle speed before turning ON the A/C clutch. If this signal is not available to the PCM, the A/C compressor will be inoperative.
CRANKSHAFT POSITION (CKP) SENSOR
The crankshaft position sensor provides a signal used by the ignition control module to calculate ignition sequence. The ignition control module also uses the crankshaft position sensor signals to initiate 18X and 3X reference pulses which the PCM uses as reference to calculate RPM and crankshaft position.
CAMSHAFT POSITION (CMP) SENSOR AND CAM SIGNAL
The camshaft position sensor sends a cam signal to the PCM which uses it as a sync pulse to trigger the injectors in proper sequence. The CAM signal is passed through the ignition control module. It is filtered and buffered by the ignition control module, but the signal is not processed in any other way. The PCM uses the CAM signal to indicate the position of the #1 piston during its power stroke. This allows the PCM to calculate true Sequential Fuel Injection (SFI) mode of operation. If the PCM detects an incorrect CAM signal while the engine is running, DTC P0341 will set.
If the CAM signal is lost while the engine is running, the fuel injection system will shift to a calculated sequential fuel injection mode based on the last fuel injection pulse, and the engine will continue to run. The engine can be restarted and will run in the calculated sequential mode as long as the fault is present with a 1 in 6 chance of injector sequence being correct. Refer to DTC P0341 for further information. Testing and Inspection