GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2008 🢒 Montana SV6 🢒 Diagnostic Navigation 🢒 Programming and Setup 🢒 Fuel Composition Diagnosis

System Description

When an E85 compatible vehicle is built, an engine control module (ECM) or powertrain control module (PCM) replaced, or when the learned alcohol content has been reset with a scan tool, the fuel system will need to contain ASTM gasoline with 10 percent or less ethanol content. If the fuel in the fuel system needs to be drained and replaced with ASTM gasoline, the engine will need to run at operating temperature and consume at least 1 liter (0.3 gallon) of fuel before the system will recognize the correct alcohol content. Either ASTM gasoline or ASTM E85 fuel can then be used.

Step

Action

Values

Yes

No

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Observe the Fuel Composition Learn parameter using the scan tool.

Does the parameter display Inactive?

--

Go to Step 4

Go to Step 3

3

Important: 

   • The key needs to be turned OFF for at least 30 seconds after the parameter displays Inactive to properly store the ethanol learned value in the ECM/PCM memory.
   • The vehicle may need to be driven more than 11 km (7 mi) with the engine at operating temperature.

Drive the vehicle until the Fuel Composition Learn parameter displays Inactive.

Does the parameter display Inactive?

--

Go to Step 4

--

4
  1. Record the ECM/PCM estimated value of the ethanol content using a scan tool.
  2. Record the actual measured percentage of content using the J 44175 Fuel Composition Tester or J-44175-A Fuel Composition Tester.

Is the ECM/PCM estimated value within 15 percent of the measured ethanol content?

--

Go to Step 11

Go to Step 5

5

Is the actual ethanol content measured with the J 44175 or J-44175-A less than 15 percent?

--

Go to Step 7

Go to Step 6

6
  1. Drain the fuel tank. Refer to Fuel Tank Draining .
  2. After the fuel tank is drained, perform a complete key cycle, key ON, engine OFF, in order to ensure that the ECM/PCM recognizes a refueling event.
  3. Key OFF, add at least 11 liters (3 gallons) of non-blended gasoline to the fuel tank.

Is the action complete?

--

Go to Step 7

--

7

Use the scan tool to reset the fuel alcohol content parameter to the specified value.

Was fuel drained from the vehicle in a previous step?

3%

Go to Step 8

Go to Step 10

8

Important: In order to ensure the non-blended gasoline has reached the fuel injectors, the vehicle may need to be driven more than 11 km (7 mi) with the engine at operating temperature.

Drive the vehicle until the Fuel Composition Learn parameter displays Inactive.

Does the parameter display Inactive?

--

Go to Step 9

--

9

Important: In order that the ECM/PCM recognizes a proper next fuel fill, the amount must be 11 liters (3 gallons) or more, and the ethanol content must be between 0-85 percent.

Refill the vehicle with drained fuel.

Is the action complete?

--

Go to Step 10

--

10

Use the scan tool to reset the fuel trim values.

Is the action complete?

--

Go to Step 11

--

11

Observe the Capture Info with a scan tool.

Are there any DTCs that have not been diagnosed?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

System OK