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No Response From PCM (PCI Bus)

NOTE: After making any repairs, perform POWERTRAIN VERIFICATION TEST  under VERIFICATION TESTS. Unless instructed otherwise in test step, reconnect any disconnected connectors.
  1. Turn ignition off. Connect scan tool to Data Link Connector (DLC). DLC is located on bottom of instrument panel, to left of brake pedal. See Figure. Turn ignition on. Using scan tool, attempt to communicate with other modules. If scan tool does not communicate with other modules, proceed to COMPLETE PCI BUS FAILURE  test. If scan tool communicates with other modules, go to next step.
  2. Turn ignition off. Disconnect Powertrain Control Module (PCM) C1 Black and C2 Gray connectors. Check, clean and repair connectors as necessary. Turn ignition on. Connect a 12-volt test light between ground and PCM Black connector terminal No. 20, fused ignition switch output start/run circuit (Dark Blue/White wire). See Figure. If test light illuminates brightly, leave PCM connectors disconnected and go to next step. If test light does not illuminate brightly, repair Dark Blue/White wire for open or high resistance.
    3. NOTE: If fused B+ circuit is open, scan tool will display NO RESPONSE.
  3. Connect 12-volt test light between ground and PCM Gray connector terminal No. 46, fused B+ circuit (Red/White wire). If test light illuminates brightly, leave PCM connectors disconnected and go to next step. If test light does not illuminate brightly, repair Red/White wire for high resistance.
  4. Connect 12-volt test light between battery voltage and PCM Black connector terminal No. 10, ground circuit (Black/Tan wire) and PCM Gray connector terminal No. 50, ground circuit (Black/Tan wire) one at a time. If test light illuminates brightly at both ground circuit terminals, go to next step. If test light does not illuminate brightly at both ground circuit terminals, repair Black/Tan wire(s) for open or high resistance at PCM connectors.
  5. Ensure ignition is off. Reconnect PCM connectors. Using scan tool, read PCM DTCs. If scan tool reads DTCs, go to next step. If vehicle starts and scan tool cannot read DTCs, perform NO RESPONSE FROM PCM (SCI ONLY)  test. If vehicle does not start and scan tool cannot read DTCs, perform NO RESPONSE FROM PCM WITH A NO START CONDITION test under STARTING in SELF-DIAGNOSTICS - NEON article.
  6. Ensure ignition is off. Disconnect PCM connectors. 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.
  7. Using scan tool, select DRB STANDALONE, LAB SCOPE, LIVE, 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.
  8. Connect Black lead to PCM Gray connector terminal No. 47, ground circuit (Black/White wire). Connect Red lead to PCM Gray connector terminal No. 59, PCI bus circuit (Violet/Yellow wire). 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 (PCM)  under REMOVAL & INSTALLATION. If voltage remains at zero volts, repair open Violet/Yellow wire to PCM.
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