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Test TC-149A: Fuel Level Sending Unit Volts Too Low

NOTE: For connector terminal identification, see CONNECTOR IDENTIFICATION . For component location and wiring diagram, see WIRING DIAGRAMS article.
  1. Using scan tool, read fuel level sending unit voltage. If voltage is less than 0.1 volt on AB and BE/BR bodies, or less than 0.2 volt on all other bodies, go to step 5)  . If voltage is not as specified, go to next step.
  2. Wiggle connectors and harness at fuel pump module while observing scan tool display. If voltage changes while wiggling connectors and harness, repair connector or harness that caused voltage change and perform TEST VER-2A: ROAD TEST VERIFICATION . If voltage does not change, go to next step.
  3. Condition required to set DTC is not present at this time. FUEL LEVEL SENDING UNIT VOLTAGE TOO LOW DTC sets if Powertrain Control Module (PCM) senses less than 0.1 volt on AB and BE/BR bodies, or less than 0.2 volt on all other bodies for 2 seconds while ignition is on. Possible causes are: fuel level sensor signal shorted to ground, defective fuel level sending unit, loss of ignition switch output voltage, defective instrument cluster circuit board, defective PCM, defective connector terminals or connector wires. Go to next step.
  4. Inspect all related wiring and connectors. Repair wiring and connectors as necessary and perform TEST VER-2A: ROAD TEST VERIFICATION . If wiring and connectors are okay, see INACTIVE DTC CONDITION . Test is complete. Perform TEST VER-2A: ROAD TEST VERIFICATION .
  5. Disconnect fuel pump module connector. Inspect connector and terminals for damage. Repair connector and terminals as necessary. If connector and terminals are okay, go to next step.
  6. Using scan tool, read fuel level sending unit voltage. If voltage is more than 3.0 volts on AB body, perform TEST TC-149B: FUEL LEVEL SENDING UNIT VOLTS TOO LOW . If voltage is more than 3.0 volts on BE/BR bodies or more than 4.5 volts on all other bodies, replace fuel pump module and perform TEST VER-2A: ROAD TEST VERIFICATION . If voltage is not as specified, go to next step.
  7. 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: ROAD TEST VERIFICATION . If connectors and terminals are okay, go to next step.
  8. Using an external ohmmeter, check resistance between ground and PCM Gray connector, fuel level sensor signal circuit (Dark Blue/Light Green wire on TJ body; Light Blue/Black wire on AB and ZJ bodies; Dark Blue wire on all other bodies). If resistance is less than 5 ohms, repair short to ground in fuel level sensor signal circuit and perform TEST VER-2A: ROAD TEST VERIFICATION . If resistance is 5 ohms or more, go to next step.
  9. Check resistance between PCM Gray connector, fuel level sensor signal circuit (Dark Blue/Light Green wire on TJ body; Light Blue/Black wire on AB and ZJ bodies; Dark Blue wire on all other bodies) and PCM Black connector, sensor ground circuit (Black/Light Blue wire). If resistance is less than 5 ohms, repair fuel level sensor signal circuit for a short to sensor ground circuit and perform TEST VER-2A: ROAD TEST VERIFICATION . If resistance is 5 ohms or more, replace PCM and perform TEST VER-2A: ROAD TEST VERIFICATION .
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