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Home >> Chrysler >> 2002 >> Intrepid Base >> Repair and Diagnosis >> Body & Frame >> Body, Cab Control Systems >> Body Control Modules >> System Tests >> Communications >> PCM (SBEC) Bus Communication Failure
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PCM (SBEC) Bus Communication Failure

NOTE: After making any repairs, perform BODY VERIFICATION TEST  under VERIFICATION TESTS.

Monitored & Set Condition

  1. When Monitored: With the ignition in run and the IOD fuse installed.
  2. Set Condition: The BCM does not receive any messages from the Powertrain Control Module (PCM) for at least 12 seconds.

Possible Causes:

Testing

  1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). Using scan tool, clear DTCs. Turn ignition on and wait one minute. Using scan tool, retrieve DTCs. If PCM BUS COMMUNICATION FAILURE DTC resets, go to next step. If PCM BUS COMMUNICATION FAILURE DTC does not reset, fault may be intermittent. Check related wiring and connectors for poor connections or damage to wiring harness. See WIRING DIAGRAMS  . Repair any problems found as necessary. If no problems are found, check if any Technical Service Bulletins (TSBs) apply to vehicle. If no TSBs apply, test is complete.
  2. Using scan tool, select BODY COMPUTER, SYSTEM TESTS, then PCM MONITOR. If scan tool displays PCM IS ACTIVE ON BUS, replace Body Control Module (BCM). See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If scan tool does not display PCM IS ACTIVE ON BUS, go to next step.
  3. Using scan tool, attempt to communicate with Powertrain Control Module (PCM). If scan tool communicates with PCM, go to next step. If scan tool does not communicate with PCM, perform NO RESPONSE FROM PCM (PCI BUS)  test.
    4. NOTE: Steps  4 - 6 are written specifically for use with Chrysler's Diagnostic Readout Box (DRBIII(R)) scan tool.
  4. Turn ignition off. Disconnect PCM Gray connector C2. Connect Scope Input Cable (CH7058) to channel one connector on scan tool. Connect Red and Black leads and Cable-To-Probe Adapter (CH7062) to scope input cable. Go to next step.
  5. Using scan tool, select DRB STANDALONE, LAB SCOPE, LIVE DATA, then 12-VOLT SQUARE WAVE. Press F2 for scope. Press F2 again and use down arrow to set voltage range to 20 volts. Press F2 again. Go to next step.
  6. Connect Black lead to chassis ground. Connect Red lead to PCM Gray connector C1 terminal No. 38, PCI bus circuit (Violet/Yellow wire). See Figure and Figure . Turn ignition on. Observe voltage display on scan tool lab scope. If voltage pulses from zero to about 7.5 volts, replace PCM. See POWERTRAIN CONTROL MODULE  under REMOVAL & INSTALLATION. See Figure -Figure . If voltage does not pulse from zero to about 7.5 volts, leave PCM Gray connector C2 disconnected and go to next step.
  7. Turn ignition off. Disconnect BCM connector C3. Measure resistance of PCI bus circuit (Violet/Yellow wire) between BCM connector C3 terminal No. 1 and PCM Gray connector C2 terminal No. 59. See Figure . If resistance is less than 5 ohms, replace BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If resistance is 5 ohms or more, repair open in Violet/Yellow wire.
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