Test TC-149A - Fuel Level Sending Unit Volts Too Low
NOTE:
For connector terminal ID, see CONNECTOR IDENTIFICATION Directory. For wiring diagram, see WIRING DIAGRAMS
article.
- Turn ignition on. Record fuel level gauge reading. Turn ignition off. Disconnect Powertrain Control Module (PCM) connector. Turn ignition on. Let fuel level gauge stabilize. If fuel level reading is not substantially different with PCM disconnected, go to next step. If fuel level reading is substantially different with PCM disconnected, replace PCM. Perform TEST VER-2A.
- Using scan tool in voltmeter mode, check voltage on fuel level signal circuit at PCM connector terminal No. 23 (Dark Blue wire). If voltage is .75 volt or more, go to next step. If voltage is less than .75 volt, go to step 6).
- While observing scan tool voltmeter, wiggle wiring harness for fuel level sending unit. If voltage changed, repair wiring harness where wiggling caused problem to appear. Perform TEST VER-2A. If voltage did not change, go to next step.
- Condition to set trouble code is not present at this time. FUEL LEVEL SENDING UNIT VOLTS TOO LOW DTC sets if PCM terminal No. 23 fuel level sensor signal circuit voltage goes less than .10 volt. Possible causes are: fuel level sensor signal circuit shorted to ground, failed fuel level sending unit, loss of ignition switch output voltage, instrument cluster printed circuit board failure or failed PCM. Go to next step.
- Inspect all related wiring and connectors and repair as necessary. If no problems were found with wiring and connectors, see INACTIVE TROUBLE CODE CONDITION . Test is complete. Perform TEST VER-2A. If related wiring and connectors were repaired, perform TEST VER-2A.
- Disconnect 4-pin fuel pump connector. Fuel pump connector is located at fuel tank. Read fuel level gauge in instrument cluster. If fuel level gauge shows empty, replace fuel level sending unit in fuel tank. Perform TEST VER-2A. If fuel level gauge does not show empty, go to next step.
- Turn ignition off. Remove instrument cluster. Using scan tool in ohmmeter mode, check resistance on left instrument cluster connector terminal No. 10 fuel level sensor signal circuit (Dark Blue wire). See Fig 1. If resistance is 5 ohms or more, go to next step. If resistance is less than 5 ohms, repair short to ground on Dark Blue wire. Perform TEST VER-2A.
- Turn ignition on. Using scan tool in voltmeter mode, check voltage on right instrument cluster connector terminal No. 5 fused ignition switch output circuit (Dark Blue/White wire). See Fig 2. If voltage is more than 8 volts, go to next step. If voltage is 8 volts or less, repair open Dark Blue/White wire. Perform TEST VER-2A.
- Turn ignition off. Connect a jumper wire between 4-pin fuel pump harness connector (at fuel tank) Dark Blue wire and ground. Using scan tool in ohmmeter mode, check resistance of low fuel sense circuit at PCM connector terminal No. 23 (Dark Blue wire). If resistance is less than 5 ohms, replace instrument cluster printed circuit board. Perform TEST VER-2A. If resistance is 5 ohms or more, repair open circuit between PCM connector terminal No. 23 and Dark Blue wire splice. Perform TEST VER-2A.