Test 5 : Fuel Gauge Inaccurate Or Inoperative (Dual Tank): Notes

Perform INSTRUMENT PANEL CLUSTER (IPC) DIAGNOSTIC SYSTEM CHECK before proceeding. See INSTRUMENT PANEL CLUSTER (IPC) DIAGNOSTIC SYSTEM CHECK under SYSTEM TEST. If INSTRUMENT PANEL CLUSTER (IPC) DIAGNOSTIC SYSTEM CHECK has been performed, go to next step.
Turn ignition switch to OFF position. Disconnect C152 connector. Connect a jumper wire between C152 connector terminal H, secondary fuel level sender signal circuit (Dark Blue wire) and terminal "K", primary fuel level sender signal circuit (Purple wire). Connect Signal Generator/Instrument Panel Tester (J-33431-C) across fuel level senders signal circuits and fuel level senders low reference circuits (Orange/Black wires). Turn ignition switch to ON position. While monitoring fuel gauge, adjust tester from 40 ohms to 250 ohms, then back to 40 ohms. At 40 ohms, fuel gauge should be near empty. At 250 ohms, fuel gauge should be near full. If fuel gauge operates properly, go to step 4. If fuel gauge does not operate properly, leave tester connected, then go to next step.
Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Using scan tool, select PCM ENHANCED EVAP DATA LIST, then FUEL LEVEL %. While monitoring scan tool, adjust tester from 40 ohms to 250 ohms. Turn ignition switch to OFF position, then adjust tester back to 40 ohms. At 40 ohms, scan tool should display 0-14%. At 250 ohms, scan tool should display 93-100%. If scan tool displays correct percentage, go to step 11. If scan tool does not display correct percentage, go to step 5.
Check for deformed primary and/or secondary fuel tanks which could cause fuel level sender float arm(s) to bind. Check for misaligned primary and secondary fuel level senders. Check for an intermittent problem caused by poor connections, a break in wire insulation, or a broken wire inside insulation. See WIRING DIAGRAMS . Repair problems as necessary. After repair, go to step 13. If no problems are found, go to step 7.
Check primary fuel level sender signal circuit (Purple wire) and secondary fuel level sender signal circuit (Dark Blue wire) for high resistance between C152 connector and VCM. See WIRING DIAGRAMS . Repair Dark Blue wire or Purple wire as necessary. After repair, go to step 13. If Dark Blue wire and Purple wire are okay, go to next step.
Check fuel level senders low reference circuits (Orange/Black wires) for high resistance. See WIRING DIAGRAMS . Repair Orange/Black wire(s) as necessary. After repair, go to step 13. If Orange/Black wires are okay, go to step 9.
Remove fuel level senders. See FUEL PUMP under FUEL SYSTEM (GASOLINE) in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS article. Check for foreign material in fuel tank which could cause fuel level sender float arms to bind. Check for stuck fuel level sender float arm. Repair problems as necessary. After repair, go to step 13. If no problems are found, go to next step.
Check resistance across fuel level senders terminals (component side) while moving fuel level sender float arm. If resistance changes smoothly, go to DIAGNOSTIC AIDS . If resistance does not change smoothly, go to step 10.
Check for poor connection at Vehicle Control Module (VCM). Repair connection as necessary. After repair, go to step 13. If connection is okay, go to step 12.
Replace primary and/or secondary fuel level sender. See FUEL PUMP under FUEL SYSTEM (GASOLINE) in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS article. After repair, go to step 13.
Replace IPC. See INSTRUMENT PANEL CLUSTER (IPC) under REMOVAL & INSTALLATION. After repair, go to step 13.
Reprogram VCM using special manufacturer's equipment. After repair, go to next step.
Using scan tool, clear DTCs. Recheck system operation. If fuel gauge is now operating properly, system is okay. If fuel gauge is not operating properly, return to step 2.