2007 Jeep Compass

Powertrain Control Module

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Operation



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

The Powertrain Control Module (PCM) is a pre-programmed, microprocessor digital computer. It regulates ignition timing, air-fuel ratio, emission control devices, charging system, certain transmission features, speed control, air conditioning compressor clutch engagement, and idle speed. The PCM can adapt its programming to meet changing operating conditions.

The PCM receives input signals from various switches and sensors. Based on these inputs, the PCM regulates various engine and vehicle operations through different system components. These components are referred to as PCM Outputs. The sensors and switches that provide inputs to the PCM are considered PCM Inputs.

The PCM adjusts ignition timing based upon inputs it receives from sensors that react to: engine RPM, Manifold Absolute Pressure (MAP), Engine Coolant Temperature (ECT), throttle position, transmission gear selection (automatic transmission), vehicle speed, and the brake switch.

The PCM adjusts idle speed based on inputs it receives from sensors that react to: throttle position, vehicle speed, transmission gear selection, engine coolant temperature, and from inputs it receives from the air conditioning clutch switch, and brake switch.

Based on the inputs that it receives, the PCM adjusts the ignition coil dwell. The PCM also adjusts the alternator charge rate through control of the alternator field and provides speed control operation.

The PCM uses the CAN-C bus to perform engine diagnostics and flash operations.

Removal & Installation



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009


WARNING
To avoid possible voltage spike damage to the PCM, the ignition key must be OFF, and the negative battery cable must be disconnected BEFORE unplugging the PCM connectors.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Unlock and disconnect the electrical connectors from the PCM.
  6.  
  7. Remove the air cleaner box.
  8.  
  9. Remove the 3 mounting bolts.
  10.  
  11. Tip the module out and remove it from the bracket.

    Click image to see an enlarged view

    Fig. Remove the 3 mounting bolts from the PCM, tip the PCM out and remove it from the bracket

  12.  

To install:


NOTE
Use the Scan tool to reprogram the new PCM with the vehicle-s original Vehicle Identification Number (VIN) and the vehicle-s original mileage. If this step is not done, a Diagnostic Trouble Code (DTC) may be set.

  1. Tip the module into the bracket.
  2.  
  3. Install the 3 mounting bolts and tighten to 80 inch lbs. (9 Nm).
  4.  
  5. Check the pins in the electrical connectors for damage. Repair as necessary.
  6.  
  7. Connect the electrical connectors and lock the connection.
  8.  
  9. Install the air cleaner box.
  10.  
  11. Connect the negative battery cable.
  12.  
  13. Use the scan tool to reprogram the new PCM with the vehicle-s original VIN and original vehicle mileage.

    Click image to see an enlarged view

    Fig. Powertrain Control Module (PCM) location

  14.  

Reset Procedure



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

A replacement PCM will require programming utilizing the StarSCAN®, or equivalent. The PCM will not operate the engine until it is programmed. A Diagnostic Trouble Code (DTC) will be set: NOT PROGRAMMED.


WARNING
Extreme care must be taken when programming a calibration into a generic PCM. Do not randomly select a calibration. Once a calibration is selected and programmed, the controller cannot be reprogrammed to a different calibration. The module can only be reprogrammed to a more recent version of that calibration.

Special Tools Required (or equivalent):



NPN: Battery Charger
 
CH9401: StarSCAN® Tool
 
CH9404: StarSCAN® Vehicle Cable
 
CH9409: StarSCAN® Documentation Kit
 
CH9410: StarSCAN® Ethernet Cable, 12 ft.
 
CH9412: StarSCAN® Software Update Device Kit
 


NOTE
If this flash process is interrupted/aborted, the flash should be restarted.


NOTE
For detailed information on the operation of the StarSCAN®, refer to the Quick Reference documentation provided in the StarSCAN® documentation kit.

  1. Open the hood, install a battery charger and verify that the charging rate provides approximately 13.5 volts. Set the battery charger timer to maintain the charging voltage for the duration of the flash process.
  2.  
  3. Connect the CH9404 StarSCAN® vehicle cable to the StarSCAN® and the vehicle.
  4.  
  5. Power ON the StarSCAN®.
  6.  
  7. Retrieve the old ECU part number. Using the StarSCAN® at the HOME screen:
    1. Select ECU VIEW.
    2.  
    3. Touch the screen to highlight the PCM in the list of modules.
    4.  
    5. Select MORE OPTIONS.
    6.  
    7. Select ECU FLASH.
    8.  
    9. Record the part number at the top of the FLASH PCM screen for later reference.
    10.  

  8.  
  9. Replace the PCM with the appropriate Generic PCM.
  10.  
  11. Insert the StarSCAN® Software Update CD into the PC. The StarSCAN® Software Update CD will start automatically. Select DOWNLOAD FLASH UPDATES.
  12.  
  13. At the SELECT A METHOD FOR LOOKING UP CONTROLLER FLASH UPDATES screen:
    1. Select ENTER PART NUMBER. Enter the PART NUMBER recorded in Step 4 when prompted to do so.
    2.  
    3. Using the mouse, highlight the appropriate CALIBRATION. Select NEXT.
    4.  
    5. Follow the on screen instructions.
    6.  
    7. When completed, proceed to Step 8.
    8.  

  14.  
  15. With the StarSCAN® powered OFF, connect the USB Key and Gender Changer to the StarSCAN® USB port.
  16.  
  17. Connect the StarSCAN® to the vehicle (if not already connected).
  18.  
  19. Power ON the StarSCAN®.
  20.  
  21. Download the flash file from the USB key to the StarSCAN®. Using the StarSCAN® at the HOME screen:
    1. Select FLASH DOWNLOAD, then select RETRIEVE FILES FROM THE USB STORAGE DEVICE.
    2.  
    3. Highlight the appropriate calibration. Select DOWNLOAD TO SCAN TOOL.
    4.  
    5. When the download is complete, select CLOSE and BACK.
    6.  

  22.  
  23. Reprogram the ECU. Using the StarSCAN® at the HOME screen:
    1. Select ECU VIEW.
    2.  
    3. Select MORE OPTIONS.
    4.  
    5. Select ECU FLASH.
    6.  
    7. Highlight the appropriate calibration.
    8.  
    9. Select UPDATE CONTROLLER. Follow the on screen instructions.
    10.  
    11. When the update is complete, select OK.
    12.  
    13. Verify the part number at the top of the FLASH PCM screen has updated to the new part number.
    14.  

  24.  
  25. Is WIN-WIRELESS NODE displayed in the ECU OVERVIEW screen list of modules-
    1. If Yes, go to Step 14.
    2.  
    3. If No, go to Step 15.
    4.  

  26.  
  27. Program the PCM to the Wireless Ignition Node (WIN). Using the StarSCAN® at the HOME screen:
    1. Select ECU VIEW.
    2.  
    3. Scroll through the list of controllers and highlight the WIN.
    4.  
    5. Select MISC. FUNCTION.
    6.  
    7. Highlight PCM REPLACED.
    8.  
    9. Select START.
    10.  
    11. Follow the on screen instructions. Select NEXT after each step. Select FINISH after completing the last step.
    12.  
    13. When complete, proceed to Step 16.
    14.  

  28.  
  29. Program the VIN into the PCM.
    1. Scroll through the list of controllers and highlight the PCM.
    2.  
    3. Select MISC. FUNCTION.
    4.  
    5. Highlight CHECK PCM VIN.
    6.  
    7. Select START.
    8.  
    9. Follow the on screen instructions. Select NEXT after each step. When the window appears with 17 boxes, select SHOW KEYBOARD. Place the cursor to the right of the last box and then backspace to delete the boxes from the window. Enter the VIN. Select FINISH after completing the last step.
    10.  
    11. Unplug the scan tool from the Data Link Connector (DLC).
    12.  
    13. At the VEHICLE DISCONNECTED screen, press OK.
    14.  
    15. Connect the scan tool to the DLC and verify that the VIN is visible at the top of the HOME screen.
    16.  

  30.  
  31. Is the vehicle equipped with a 3.7L or 4.7L engine-
    1. If Yes, go to Step 18.
    2.  
    3. If No, go to Step 17.
    4.  

  32.  
  33. Using the StarSCAN® at the HOME screen:
    1. Select ECU VIEW.
    2.  
    3. Scroll through the list of controllers and highlight the PCM.
    4.  
    5. Select MISC. FUNCTION.
    6.  
    7. Highlight LEARN ETC.
    8.  
    9. Select START.
    10.  
    11. Follow the on screen instructions. Select NEXT after each step. Select FINISH after completing the last step.
      NOTE
      Due to the PCM programming procedure, a DTC may be set in other modules (TCM, BCM, MIC, SKIM, etc.) within the vehicle, if so equipped. Some DTC's may cause the MIL to illuminate. Check all modules using ECU VIEW from the HOME screen, record the DTC's, and erase these DTC's. Erase any DTC's in the PCM only after all other modules have had their DTC's erased.


      NOTE
      The following step is required by law.

    12.  

  34.  
  35. Type the necessary information on the AUTHORIZED MODIFICATION LABEL p/n 04275086AB and attach it near the VECI label.
  36.  

Testing



Specific to:

Jeep Compass 2007-2009

Jeep Patriot 2007-2009

  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Start the engine and allow it to reach normal operating temperature. Using a diagnostic scan tool, check for the presence of any Diagnostic Trouble Codes (DTC-s). Record and address these codes, as necessary.
  4.  
  5. Refer to any Technical Service Bulletins (TSB-s) that may apply.
  6.  
  7. Review the scan tool Freeze Frame information. If possible, try to duplicate the conditions under which the DTC set.
  8.  
  9. With the engine running at normal operating temperature, monitor the scan tool parameters related to the DTC while wiggling the wire harness. Look for parameter values to change and/or a DTC to set. Turn the ignition OFF .
  10.  
  11. Visually inspect the related wire harness. Disconnect all the related harness connectors. Look for any chafed, pierced, pinched, or partially broken wires, and broken, bent, pushed out, or corroded terminals. Perform a voltage drop test on the related circuits between the suspected inoperative component and the PCM.
    WARNING
    Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal-to-pin connection. Install Miller Special Tool No. 8815 to perform diagnosis.

  12.  
  13. Inspect and clean all PCM, engine, and chassis grounds that are related to the most current DTC.
  14.  
  15. If numerous trouble codes were set, use a wire schematic and look for any common ground or supply circuits.
  16.  
  17. For any Relay DTC-s, actuate the Relay with the scan tool and wiggle the related wire harness to try to interrupt the actuation.
  18.  
  19. For intermittent Evaporative Emission trouble codes perform a visual and physical inspection of the related parts including hoses and the Fuel Filler cap.
  20.  
  21. Use the scan tool to perform a System Test if one applies to the failing component. A co-pilot, data recorder, and/or lab scope should be used to help diagnose intermittent conditions.

    Click image to see an enlarged view

    Fig. PCM connector view C1



    Click image to see an enlarged view

    Fig. PCM connector view C2

  22.  

 
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