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Home >> Jeep >> 1996 >> Cherokee Classic, Part Time, Standard >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Controls - Tests W/Codes - 4.0L >> Diagnostic Trouble Code (DTC) Identification >> Test TC-101A - Fuel Pump Relay Control Circuit

Test TC-101A - Fuel Pump Relay Control Circuit

NOTE: For connector terminal identification, refer to CONNECTOR IDENTIFICATION . For wiring diagram, see WIRING DIAGRAMS article in this section.
  1. Use scan tool to actuate Fuel Pump (FP) relay. If FP relay does not click, go to step 5). If FP relay clicks, go to next step.
  2. Condition required to set DTC is not present at this time. FUEL PUMP RELAY CONTROL CIRCUIT DTC sets if an open or short is detected in FP relay circuit. Possible causes are: open or short in FP relay control circuit, open or short in FP relay fused ignition switch output circuit, FP relay coil open or shorted, inoperative circuit driver in Powertrain Control Module (PCM) or PCM failure. Go to next step.
  3. Inspect all related wiring and connectors. Repair wiring and connectors as necessary and perform TEST VER-2A . If wiring and connectors are okay, go to next step.
  4. Start engine. Wiggle wiring harness from FP relay to PCM. If engine stalls while wiggling wiring harness, repair wiring harness as necessary and perform TEST VER-2A. If engine does not stall while wiggling wiring harness, see INACTIVE DTC CONDITION . Test is complete. Perform TEST VER-2A.
  5. Remove FP relay. Inspect FP relay connector and terminals for damage. Repair connector and terminals as necessary and perform TEST VER-2A. If connector and terminals are okay, go to next step.
  6. Using scan tool in voltmeter mode, check voltage on FP relay connector, fused ignition switch output circuit (Dark Blue wire). If voltage is 10 volts or less, repair open fused ignition switch output circuit and perform TEST VER-2A . If voltage is more than 10 volts, go to next step.
  7. Using an external ohmmeter, check resistance across FP relay terminals. See Figure. If resistance is 100 ohms or more, replace FP relay and perform TEST VER-2A. If resistance is less than 100 ohms, go to next step.
  8. Turn ignition off. Disconnect Powertrain Control Module (PCM) connectors. Inspect connectors and terminals for damage. Repair connectors and terminals as necessary and perform TEST VER-2A. If connectors and terminals are okay, go to next step.
  9. Using scan tool in ohmmeter mode, check resistance of PCM Gray connector, FP relay control circuit (Brown wire). If resistance less than 5 ohms, repair short to ground FP relay control circuit and perform TEST VER-2A. If resistance is 5 ohms or more, go to next step.
  10. Using an external ohmmeter, check resistance of FP relay control circuit (Brown wire) between FP relay connector and PCM Gray connector. If resistance is 5 ohms or more, repair open FP relay control circuit and perform TEST VER-2A . If resistance is less than 5 ohms, replace PCM and perform TEST VER-2A.
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