Mazda Trucks 1987-1993 Repair Guide



The PCM/ECM receives data from a number of sensors and other electronic components (switches, relay, etc.). Based on information received and information programmed in the PCM/ECM's memory, it generates output signals to control various relay, solenoids and other actuators. The PCM/ECM in this system has calibration modules located inside the assembly that contain calibration specifications for optimizing emissions, fuel economy and driveability. The calibration module is called a PROM.

The following are the electronic engine controls used by Mazda trucks (note that not all of these sensors may be found on one engine):

Powertrain Control Module (PCM)
Throttle Position (TP) sensor
Mass Air Flow (MAF) sensor
Intake Air Temperature (IAT) sensor
Idle Air Control (IAC) valve
Engine Coolant Temperature (ECT) sensor
Oxygen Sensor or Heated Oxygen Sensor (HO2S)
Camshaft Position (CMP) sensor
Knock Sensor (KS)
Vehicle Speed Sensor (VSS)
Crankshaft Position (CKP) sensor

Because of the complicated nature of this system, special tools and procedures are necessary for testing and troubleshooting.