DTC P0461 Fuel Level Sensor Performance. Chevrolet Metro 2001

For 1990-2009 cars

Table 1: | Fuel Level Sensor Inspection

Engine Controls Components
Cell 21: Fuel Supply System
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The powertrain control module (PCM) uses input from the fuel level sensor to calculate expected vapor pressures within the fuel system. Vapor pressures vary as the fuel level changes. Vapor pressure is critical to determining if the EVAP control system is operating properly. Fuel level information is used in determining whether to run an EVAP control system diagnostic. A fuel level that is too high or too low may prevent the EVAP control system diagnostics from accurately detecting a fault.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

The change in fuel level from maximum to minimum is less than 1 gallon even though the volume of intake air is calculated to be more than 660 kg.

### Action Taken When the DTC Sets

• | The PCM illuminates the malfunction indicator lamp (MIL) after two consecutive ignition cycles in which the diagnostic runs with the fault active.

• | The PCM records the operating conditions at the time the diagnostic fails. This information is stored in the Freeze Frame buffer.

### Conditions for Clearing the MIL/DTC

• | The MIL turns OFF after three consecutive trips during which the diagnostic runs and no fault is detected.

• | A History DTC will clear after 40 consecutive warm-up cycles without a fault.

• | DTCs can be cleared by using a scan tool or by disconnecting the PCM battery feed.

### Diagnostic Aids

Check for any of the following conditions:

• | If a DTC P0463 is also displayed, diagnose that DTC first.

• | A stuck fuel level sensor may cause a DTC P0461 to set.

• | A loose fuel tank baffle may interfere with the movement of the fuel level sensor float.

• | A corroded or loose fuel level sensor chassis ground--Operate the tail lamps and brake lamps while checking the fuel level sensor reading on a scan tool. Increasing the current flow through the G400 chassis ground can reveal a faulty circuit connection.

• | A faulty electrical connection at the PCM.

Check the resistance of the fuel level sensor at the following positions:

#### Fuel Level Sensor Inspection

Fuel Level Position | Resistance Measurement
--- | ---
Full Tank | 10 ohms or less
Half Tank | 30 to 35 ohms
Empty Tank | 120 ohms or more

An open in the fuel level sensor circuit will indicate a 0 percent fuel level (empty fuel tank), while a short to ground in the fuel level sensor circuit will indicate a 100 percent fuel level (full fuel tank).

An intermittent malfunction may be caused by a fault in the fuel level sensor electrical circuit. Inspect the wiring harness and components for any of the following conditions:

• | Backed out terminals

• | Improper mating of terminals

• | Broken electrical connector locks

• | Improperly formed or damaged terminals

• | Faulty terminal to wire connections

• | Physical damage to the wiring harness

• | A broken wire inside the insulation

• | Corrosion of electrical connections, splices, or terminals

If the DTC P0461 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.

### Test Description

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

1. The Powertrain OBD System Check prompts the technician to complete some basic checks, and to save the applicable Freeze Frame data on the scan tool. This creates an electronic copy of the data that was taken when the fault occurred. The scan tool saves the information for later reference.

2. This step checks the circuit from the fuel level sensor to the PCM. The scan tool will display a default value of 100 percent all the time if a DTC for a fuel level sensor circuit is present.Current DTCs or saved DTCs for a fuel level sensor circuit must be cleared before reading the fuel level parameter.

3. This step checks for a faulty fuel level sensor.

| Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check

2

1. Remove the rear seat cushion. Refer to Rear Seat Cushion Replacement in Body and Accessories.
2. Disconnect the harness electrical connector C310 at the fuel level sensor.
3. Turn ON the ignition, leaving the engine OFF.
4. Measure the signal voltage at the PCM side of the fuel level sensor connector with a DMM.

Is the voltage near the specified value?

7-8 V

Go to Step 3

Go to Step 7

3

1. Reconnect the harness connector C310 at the fuel level sensor.
2. Remove the fuel tank from the vehicle. Refer to Fuel Tank Replacement .
3. Disconnect the electrical connector in the fuel sender assembly at the fuel sender.
4. Measure the signal voltage at the PCM side of the fuel level sensor with a DMM.

Is the voltage near the specified value?

7-8 V

Go to Step 4

Go to Step 8

4

1. Check for a correct ground connection at the fuel tank.
2. Repair the connection as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 14

Go to Step 5

5

Important: The current or the saved fuel level DTCs should be cleared from the scan tool in order to avoid an inaccurate fuel level reading.

1. Remove the fuel tank level sensor from the fuel tank. Refer to Fuel Level Sensor Replacement .
2. Reconnect the electrical connector in the fuel tank sender assembly.
3. Monitor the fuel tank level on the scan tool while moving the fuel level float from the empty position and back to the full position. Repeat the procedure several times.

Does the fuel tank level increase to the first specified value, and decrease to the second specified value when the float is moved from one end to the other?

90%

0%

Go to Diagnostic Aids

Go to Step 6

6

Important: The fuel gauge responds slowly to changes in the position of the fuel sensor float.

Continue to move the fuel tank sensor float from the empty position back to the full position while observing the fuel gauge on the instrument panel (IP).

Does the IP fuel gauge indicate a full fuel tank and an empty fuel tank when the float moves from one end to the other?

--

Go to Step 12

Go to Step 9

7

1. Check for an open or for a short in the signal wire from the fuel level sensor, between the harness connector C310 and the PCM.The harness connector C310 is located under the rear seat cushion.
2. Repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 14

Go to Step 10

8

Repair the open or the short in the signal wire from the fuel level sensor between the harness connector C310 and the fuel level sensor.The harness connector C310 is located under the rear seat cushion. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

--

Go to Step 14

--

9 | Replace the fuel level sensor. Refer to Fuel Level Sensor Replacement . Is the action complete? | -- | Go to Step 14 | --

10

1. Turn OFF the ignition.
2. Leave the harness connector C310 on the fuel level sensor disconnected.
3. Disconnect the PCM electrical connector.
4. Turn ON the ignition, leaving the engine OFF.
5. Measure the signal terminal from the harness side of the fuel level sensor with a DMM.

Is the voltage within the specified value?

7-8 V

Go to Step 13

Go to Step 11

11

1. Check for an open or for a short signal circuit from the fuel level sensor between the PCM and the IP fuel gauge.
2. Repair any condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 14

Go to Instrument Cluster System Check

12

1. Check for an open in the signal circuit from the fuel level sensor between the PCM and the IP fuel gauge.
2. Repair any condition as necessary. Refer to Wiring Repairs in Wiring Systems.

Was a repair necessary?

--

Go to Step 14

Go to Step 13

13 | Replace the PCM. Is the action complete? | -- | Go to Step 14 | --

14

1. Perform the Clear DTC Information function on the scan tool, and road-test the vehicle within the Freeze Frame conditions which set the DTC.
2. Review the scan tool data, and check the data for DTCs. The repair is complete if no DTCs are displayed.

Are any DTCs displayed on the scan tool?

-

Go to the applicable DTC table

System OK