GM Service Manual Online
For 1990-2009 cars only

Object Number: 53090  Size: MF
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice
Engine Controls Components
Fuel Controls
OBD II Symbol Description Notice

Circuit Description

The Fuel Level sensor is an important input to the VCM for the Enhanced Evaporative System Diagnostic. The VCM needs the fuel level information in order to know the volume of fuel in the tank. The fuel level affects the rate of change in the air pressure in the EVAP system. Several of the Enhanced Evaporative System Diagnostic sub-test are dependent upon the correct fuel level information. The diagnostic will not run when the tank is greater than 85% or less than 15% full. (This sensor signal disables the misfire when the fuel levels are less than 15%). This DTC is a type D DTC.

Conditions for Setting the DTC

    • The Fuel Tank Level Slosh Test is completed.
    • The Tank Level Main Test is completed.
    • The Fuel Tank Level Data is Valid.
    • The Fuel Level signal is unchanged over a distance of 200 miles.

Action Taken When the DTC Sets

    • The control module stores the DTC in history after the first failure but will not illuminate the malfunction indicator lamp (MIL).
    • The control module records the operating conditions at the time the diagnostic fails. The control module stores the failure information in the scan tools Freeze Frame/Failure Records.

Conditions for Clearing the MIL/DTC

The VCM turns OFF the MIL after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (the coolant temperature has risen 22°C (40°F) from the start-up coolant temperature and the engine coolant temperature exceeds 71°C (160°F) during that same ignition cycle) or the scan tool clearing feature has been used.

Test Description

The number below refers to the step number in the diagnostic table.

  1. This step determines if the fuel gauge and fuel level sender module are operating correctly.

Step

Action

Value(s)

Yes

No

1

Was the On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Install the scan tool.
  2. Turn ON the ignition.
  3. Compare the fuel level on the scan tool with the vehicle fuel gauge.

Are the levels approximately the same?

--

Go to Step 3

Go to Step 5

3

  1. Record the vehicle fuel gauge reading.
  2. Turn OFF the ignition.
  3. Disconnect the black VCM connector.
  4. Turn ON the ignition.

Did the vehicle fuel gauge reading change?

--

Go to Step 4

Go to Step 5

4

  1. Turn ignition OFF.
  2. Locate the fuel level sender connector under the vehicle just forward of the fuel tank.
  3. Disconnect the fuel level sender connector.
  4. Using a fused jumper wire, jump the fuel level input to the fuel level sensor ground.
  5. Turn the ignition ON.

Does the scan tool and the fuel gauge indicate the specified values?

0%

Empty

Go to Step 5

Go to Step 6

5

Refer to Engine Electrical for Fuel Sender Gauge Module Diagnosis.

--

--

--

6

Replace VCM.

Important:  If the VCM is malfunctioning, program the new VCM. Refer to VCM Replacement/Programming .

Is the action complete?

--

Go to Step 7

--

7

  1. Using the scan tool, select the DTC, select the DTC and the Clear Info.
  2. Start the engine.
  3. Idle at the normal operating temperature.
  4. Select the DTC and the Specific.
  5. Enter the DTC number which was set.
  6. Operate the vehicle withnin the conditions for setting this DTC as specified in the supporting text.

Does the scan tool indicate that this diagnostic Ran and Passed?

--

Go to Step 8

Go to Step 2

8

Using the scan tool, select the Capture Info and the Review Info.

Are any DTCs displayed that have not been diagnosed?

--

Go to the Applicable DTC Table

System OK