Ford Crown Victoria/Grand Marquis 1989-1998

Powertrain Control Module (PCM)



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: The calibration code will be needed to replace the PCM or any electrical engine control sensors. The calibration code can typically be found on a label affixed on the driver's door or the door jam

The Powertrain Control Module (PCM) performs many functions on your vehicle. The module accepts information from various engine sensors and computes the required fuel flow rate necessary to maintain the correct amount of air/fuel ratio throughout the entire engine operational range.

Based on the information that is received and programmed into the PCM's memory, the PCM generates output signals to control relays, actuators and solenoids. The PCM also sends out a command to the fuel injectors that meters the appropriate quantity of fuel. The module automatically senses and compensates for any changes in altitude when driving your vehicle.


It is located in the engine compartment, attached to the firewall on the driver's side, near the master cylinder.

Never detach the Powertrain Control Module (PCM) with the battery connected. Be sure to wear a grounding device when removing or installing a PCM to prevent damage to the unit due to static electricity.

  1. Disconnect the negative battery cable.
  3. Wearing a grounding device, loosen the engine control sensor wiring harness connector retaining bolt and carefully detach the harness connector from the PCM.
  5. Remove the PCM bracket clip from the module bracket and remove the PCM.

To install:
  1. Wearing a grounding device, install the PCM to the mounting bracket and secure the bracket clip.
  3. Carefully fit the engine control sensor wiring harness connector to the PCM and secure with the retaining bolt. Torque the retaining bolt to 32 inch lbs. (3.7 Nm).
  5. Reconnect the negative battery cable.
  7. Check for proper operation.