Escalade, Suburban, Tahoe, Yukon, Denali, DenaliXL, YukonXL 1999-2005

Powertrain Control Module



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

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 module automatically senses and compensates for any changes in altitude when driving your vehicle.

Removal & Installation

It is necessary to record the remaining engine oil life. If the replacement module is not programmed with the remaining engine oil life, the engine oil life will default to 100 percent. If the replacement module is not programmed with the remaining engine oil life, the engine oil must be changed at 3,000 miles (5,000km) from the last oil change. A scan tool must be used to retrieve the PCM data. This information must be transferred to the new PCM.

  1. Disconnect the negative battery cable.
  3. Disengage the harness connections from the PCM.
  5. Disengage the retainer tabs securing the PCM to the bracket. Remove the PCM from the engine compartment.
  7. Installation is the reverse of removal. Program the PCM.

    Click image to see an enlarged view

    Fig. PCM mounting



Service of the Powertrain Control Module (PCM) should consist of either replacement of the PCM or programming of the Electrically Erasable Programmable Read Only Memory (EEPROM). If the diagnostic procedures call for the PCM to be replaced, the replacement PCM should be checked to ensure that the correct part is being used. If the correct part is being used, remove the faulty PCM and install the new service PCM