GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2005 🢒 Equinox 🢒 Vehicle Control Systems 🢒 Vehicle DTC Information 🢒 Fuel Gage Inaccurate or Inoperative

Diagnostic Aids
    • Ensure that the fuel level is in the same range as the customer concern.
    • For intermittent diagnosis, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
    • Refer to Fuel Level Specifications in order to verify the correct fuel level sensor readings. The Fuel Level parameter is available on the scan tool in the Powertrain Fuel and Emissions data list. The Fuel Gage Position parameter is available in the Body Control Module Accessory data list.

Test Description

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

  1. This step tests for a high resistance in the signal circuit and the low reference circuit of the fuel level sensor.

    2.

  2. DTCs will be set in the PCM when you perform this diagnostic table.

Step

Action

Value(s)

Yes

No

Schematic Reference: Instrument Cluster Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

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 ON the ignition, 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 ohms.
  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?

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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.

  3. Vary the resistance on the J 33431-C from 40-250 ohms.
  4. Refer to Fuel Level Specifications in order to convert from resistance to fuel level percent.

    5. Important: Turn OFF the ignition momentarily between the resistance settings in order to quickly update the scan tool display.

  5. With the scan tool, observe the Fuel Level Sensor parameter in the Powertrain EVAP Data, data list.

Does the Fuel Level Sensor parameter display the correct fuel level amount?

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Go to Step 9

Go to Step 5

4

Inspect for the following items:

    • A poor connection at the harness connector of the fuel level sensors
         Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems.
    • A high resistance in the signal circuit or the low reference circuit between the fuel level sensor and C406
    • A misaligned fuel level sender
    • A deformed fuel tank

Did you find and correct the condition?

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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?

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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?

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Go to Step 15

Go to Step 10

7
  1. Remove the fuel level senders.
  2. Inspect for the following items:
    3. • 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?

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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 ohms

Go to Diagnostic Aids

Go to Step 11

9
  1. Turn ON the ignition, 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 ohms.
  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 Gage Position parameter in the Body Control Module (BCM) Accessory data list and the Fuel Level Sensor parameter in the Powertrain EVAP Data, data list.

Does the Fuel Gage Position parameter match the Fuel Level Sensor parameter?

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Go to Step 12

Go to Step 14

10

Inspect for poor connections at the harness connector of the powertrain control module (PCM). 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 fuel level sensor with the abnormally high resistance. Refer to Primary Fuel Level Sensor Replacement or to Secondary Fuel Level Sensor Replacement in Engine Controls - 3.4L.

Did you complete the replacement?

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Go to Step 15

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12

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?

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Go to Step 15

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13

Replace the PCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

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Go to Step 15

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14

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming.

Did you complete the replacement?

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Go to Step 15

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15

  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?

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System OK

Go to Step 2