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Home >> Chevrolet >> 2005 >> Chevy Express H1500, Van Passenger >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Instrument Panel System Displays, Gauges And Console >> Diagnostic Information and Procedures >> Fuel Gage Inaccurate or Inoperative (Dual Tank) >> Test Description

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 3:  This step tests for a high resistance in the signal circuit and the low reference circuit of the fuel level sensor.
  2. 13:  DTCs will set in the powertrain control module (PCM) when you perform this diagnostic table.
Fuel Gage Inaccurate or Inoperative (Dual Tank)

Step Action Value(s) Yes No
Schematic Reference: Instrument Cluster Schematics 
Connector End View References: Instrument Panel, Gages, and Console Connector End Views , Powertrain Control Module (PCM) Connector End Views in Engine Controls - 4.3L or Powertrain Control Module (PCM) Connector End Views in Engine Controls - 4.8L, 5.3L, and 6.0L
1 Did you perform the Diagnostic System Check - Vehicle? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Disconnect C101.
  2. Connect a jumper wire between the signal circuit of the primary fuel level sender and the signal circuit of the secondary fuel level sender, female terminal side.
  3. Connect the J 33431-C  Signal Generator and Instrument Panel Tester between the signal circuit of the fuel level sensor and the low reference circuit of the fuel level sensor on the female terminal side of the connector. See Special Tools .
  4. Turn ON the ignition, with the engine OFF.
    5. IMPORTANT: Verify the J 33431-C  resistance settings with a DMM. See Special Tools .
  5. Vary the resistance on the J 33431-C  from 40-250 ohms. See Special Tools .
  6. Refer to Fuel Level Specifications  in order to convert from resistance to fuel gage display.
Does the fuel gage display the correct fuel level?		 - Go to Step 4  Go to Step 3 
3 
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
    3. IMPORTANT: Verify the J 33431-C  resistance settings with a DMM. See Special Tools .
  3. Vary the resistance on the J 33431-C  from 40-250 ohms. See Special Tools .
  4. Refer to Fuel Level Specifications  in order to convert from resistance to fuel level percentage.
    5. IMPORTANT: Turn the ignition OFF momentarily between the resistance settings in order to quickly update the scan tool display.
  5. With the scan tool, observe the Fuel Tank Level Remaining % parameter in the powertrain control module (PCM) Enhanced EVAP data list.
Does the Fuel Tank Level Remaining % parameter display the correct fuel level percentage?		 - Go to Step 11  Go to Step 5 
4 Inspect for the following items:
  • A poor connection at the harness connector of the fuel level senders-Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
  • A high resistance in the primary and secondary signal circuits or the primary and secondary low reference circuits between the fuel level sender and C101
  • A misaligned fuel level sender
  • A deformed primary or secondary fuel tank

Did you find and correct the condition?		 - Go to Step 13  Go to Step 7 
5 Test the signal circuits of the primary and secondary fuel level senders for a high resistance between C101 and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 6 
6 Test the low reference circuit of the primary and secondary fuel level senders for a high resistance between C101 and the PCM. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 9 
7
  1. Remove the fuel level senders.
  2. Inspect for the following items:
    • The fuel level sender is stuck, perhaps due to an interference with the fuel strainer.
    • The fuel tank contains foreign material, for instance, ice.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 8 
8
  1. With the DMM, measure the resistance of the fuel level senders while moving the float arm.
  2. Observe both the analog and digital displays on the DMM.
Does the resistance change smoothly across the specified range?		 40-250 Ω Go to Diagnostic Aids Go to Step 10 
9 Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 13  Go to Step 12 
10 Replace the fuel level sender. Refer to appropriate procedure:
Did you complete the replacement?		 - Go to Step 13  -
11 Replace the instrument panel cluster (IPC). Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 13  -
12 Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.
Did you complete the replacement?		 - Go to Step 13  -
13 
  1. Use the scan tool in order to clear the PCM DTCs.
  2. Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 2 
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