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Test Description

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step number 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. 15:  DTCs will be set in the ECM when you perform this diagnostic table.
Fuel Gage Inaccurate or Inoperative

Step Action Value(s) Yes No
Schematic Reference:  Instrument Cluster Schematics  
1 Did you perform the Instrument Cluster Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - Instrument Cluster 
2
  1. Disconnect C406.
  2. 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 male terminal side.
  3. Turn the ignition ON, with the engine OFF.
    4. IMPORTANT: Verify the J 33431-C resistance settings with a DMM.
  4. Vary the resistance on the J 33431-C from 40-250 Ω.
  5. 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 the ignition ON, with the engine OFF.
    3. IMPORTANT: Verify the J 33431-C resistance settings with a DMM.
  3. Vary the resistance on the J 33431-C from 40-250 Ω.
  4. Refer to Fuel Level Specifications  in order to convert from resistance to fuel level percent.
    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 Level parameter in the Powertrain Fuel and Emissions data list.
Does the Fuel Level parameter display the correct fuel level amount?		 - Go to Step 9  Go to Step 5 
4 Inspect for the following items:
Did you find and correct the condition?		 - Go to Step 15  Go to Step 7 
5 Test the signal circuit of the fuel level sensor for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 6 
6 Test the low reference circuit of the fuel level sensor for a high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 10 
7
  1. Remove the fuel level senders.
  2. Inspect for the following items:
    • A stuck fuel level sensor, i.e. the fuel strainer interfering with the sender float arm.
    • Foreign material in the fuel tank, i.e. ice.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 8 
8
  1. With the J 39200  DMM, measure the resistance of both fuel level sensors 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 on both fuel level sensors?		 20-125 Ω Go to Diagnostic Aids Go to Step 11 
9
  1. Turn the ignition ON, with the engine OFF.
    2. IMPORTANT: Verify the J 33431-C resistance settings with a DMM.
  2. Vary the resistance on the J 33431-C from 40-250 Ω.
  3. Refer to Fuel Level Specifications  in order to convert from resistance to fuel level percent.
    4. IMPORTANT: Turn the ignition OFF momentarily between the resistance settings in order to quickly update the scan tool display.
  4. With the scan tool, observe the Fuel Gauge Position parameter in the Body Control Module Accessory data list and the Fuel Level parameter in the Powertrain Fuel and Emissions data list.
Does the Fuel Gauge Position parameter match the Fuel Level parameter?		 - Go to Step 12  Go to Step 14 
10 Inspect for poor connections at the harness connector of the ECM. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 15  Go to Step 13 
11 Replace the malfunctioning fuel level sensor. Refer to FUEL LEVEL SENDER UNIT & FLOAT .
Did you complete the replacement?		 - Go to Step 15  -
12 Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement .
Did you complete the replacement?		 - Go to Step 15  -
13 Replace the ECM. Refer to ENGINE CONTROL MODULE .
Did you complete the replacement?		 - Go to Step 15  -
14
IMPORTANT: Program the replacement BCM.
Replace the BCM. Refer to Body Control Module Replacement in Body Control System.Did you complete the replacement?		 - Go to Step 15  -
15 
  1. Use the scan tool in order to clear the ECM 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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