2002 CHEVROLET AVEO sensor

DTC P0461
Circuit Description
The fuel level sensor changes resistance based on fuel level. The fuel level sensor has a signal circuit and a
ground circuit. The engine control module (ECM) applies 5 volts on the signal circuit to the sensor. The ECM
monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine fuel
level.
When the fuel tank is full, the sensor resistance is low, and the ECM signal voltage is high. When the fuel tank
is empty, the sensor resistance is high, and the signal voltage is low.
The ECM uses inputs from the fuel level sensor in order to calculate the total fuel percentage remaining in the
fuel tank. The ECM uses the fuel level information for the evaporative emission (EVAP) and misfire
diagnostics. The fuel level information is sent to the instrument panel cluster (IPC).
This diagnostic tests for a stuck fuel level sensor signal. If the fuel level signal appears to be stuck, based on a
lack of signal variation expected during normal operation, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0461 Fuel Level Sensor Circuit Performance
Conditions for Running the DTC
DTCs P0462, P0463, and P0502 are not set.
The engine is running.
DTC P0461 runs continuously once the above conditions are met.
Conditions for Setting the DTC
The ECM does not detect a decrease in fuel level over a distance of 250 Km (155 miles).
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition
cycle that the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The first time the
dia
gnostic fails, the control module stores this information in the Failure Records. If the diagnostic
P0461DTC P0461 ECM
P0462DTC P0462 ECM
P0463DTC P0463 ECM
P0464DTC P0464 ECM

2005 Chevrolet Aveo
2005 ACCESSORIES & EQUIPMENT Instrument Panel, Gages, & Console - Aveo
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reports a failure on the second consecutive ignition cycle, the control module records the operating
conditions at the time of the failure. The control module writes the operating conditions to the Freeze
Frame and updates the Failure Records.
The fuel gage defaults to empty.
Conditions for Clearing the MIL/DTC
The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and
does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Check for the following conditions:
A poor connection or damaged harness-Inspect ECM harness connectors for the following:
Backed out terminals
Improper mating
Broken locks
Poor wire to terminal connections
Intermittent test-Monitor a scan tool or digital voltmeter connected between the related circuits while
moving the connectors and harnesses. If the failure is induced, the voltage reading will change. This will
help locate a circuit condition. Refer to the following:
Intermittent Conditions
in Engine Controls - 1.6L (L91)
Test Description
The numbers below refer to the step numbers on the diagnostic table.
2: This step determines if the fault is present.
3: This step determines if the fuel level sensor signal and ground circuits are OK.
DTC P0461
StepActionValueYesNo
Schematic Reference: Instrument Cluster Schematics
Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views

1
Did you perform the Diagnostic System Check -
Instrument Cluster?
-
Go to
Diagnostic
System Check
- Instrument

2005 Chevrolet Aveo
2005 ACCESSORIES & EQUIPMENT Instrument Panel, Gages, & Console - Aveo
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Friday, July 31, 2009 1:07:02 PMPage 15 © 2005 Mitchell Repair Information Company, LLC.

Go to Step 2 Cluster
2
Refer to DTC P0462 or DTC P0463 .
1. Turn OFF the ignition.
2. Disconnect the fuel level sender through
the access panel under the rear seat.
3. Jumper the fuel level sensor signal circuit
to a known good ground.
4. Turn ON the ignition, with the engine
OFF.
5. Observe the Fuel Level Sensor voltage
parameter with a scan tool.
Is the fuel level voltage at the specified value?
IMPORTANT:
If DTCs P0462 or P0463 are also set, diagnose
those DTCs first.
5 V
Go to Step 3 Go to Step 5
3
1. Jumper the fuel level sensor signal circuit
and low reference circuits together.
2. Observe the Fuel Level Sensor voltage
parameter with a scan tool.
Is the fuel level sensor voltage at the specified
value?
5 V
Go to Step 4 Go to Step 6
4
1. Remove the fuel sender assembly.
Refer to the following:
Fuel Sender Assembly Replacement
in
Engine Controls - 1.6L (L91)
2. Inspect for the following:
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).
A fuel tank that is deformed
3. If you find a condition, repair the
condition as necessary.
Did you find and correct the condition?

Go to Step 10 Go to Step 7

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5
Test the fuel level signal sensor circuit for an
open or high resistance. Refer to Testing for
Continuity and Wiring Repairs in Wiring
Systems.
Did you find and correct the condition?-
Go to Step 10 Go to Step 8
6
Test the low reference circuit and the fuel level
signal circuit for an open or high resistance.
Refer to Testing for Continuity
and Wiring
Repairs in Wiring Systems.
Did you find and correct the condition?
-
Go to Step 10 Go to Step 8
7
Replace the fuel level sender assembly. Refer to
the following:
Fuel Sender Assembly Replacement
in Engine
Controls - 1.6L (L91)

Did you complete the replacement?-
Go to Step 10 -
8
Test for an intermittent and for a poor connection
at the control module. Refer to Testing for
Intermittent Conditions and Poor
Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?-
Go to Step 10 Go to Step 9
9
Replace the control module. Refer to the
following:
Engine Control Module (ECM) Replacement

in Engine Controls - 1.6L (L91)

Did you complete the replacement?-
Go to Step 10 -
10
1. Clear the DTCs with a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions
for Running the DTC. You may also
operate the vehicle within the conditions
that you observed from the Freeze
Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 11 Go to Step 2
Observe the Capture Info with a scan tool.
Go to
Diagnostic
Trouble Code

2005 Chevrolet Aveo
2005 ACCESSORIES & EQUIPMENT Instrument Panel, Gages, & Console - Aveo
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Friday, July 31, 2009 1:07:02 PMPage 17 © 2005 Mitchell Repair Information Company, LLC.

DTC P0462
Circuit Description
The fuel level sensor changes resistance based on fuel level. The fuel level sensor has a signal circuit and a
ground circuit. The engine control module (ECM) applies 5 volts on the signal circuit to the sensor. The ECM
monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine fuel
level.
When the fuel tank is full, the sensor resistance is low, and the ECM signal voltage is high. When the fuel tank
is empty, the sensor resistance is high, and the signal voltage is low.
The ECM uses inputs from the fuel level sensor in order to calculate the total fuel percentage remaining in the
fuel tank. The ECM uses the fuel level information for the evaporative emission (EVAP) and misfire
diagnostics. The fuel level information is sent to the instrument panel cluster (IPC).
If the ECM detects a signal voltage lower than the operating range of the sensor, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0462 Fuel Level Sensor Circuit Low Voltage
Conditions for Running the DTC
The engine is running.
DTC P0462 runs continuously once the above conditions are met.
Conditions for Setting the DTC
The ECM detects that fuel level signal voltage is less than 0.25 volts.
The above condition is present for more than 10 seconds.
Action Taken When the DTC Sets
The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
The control module records the operating conditions at the time the diagnostic fails. The control module
stores this information in the Freeze Frame/Failure Records.
The fuel gage defaults to empty.
Conditions for Clearing the MIL/DTC
11
Are there any DTCs that have not been
diagnosed?
-
(DTC) List in
Engine Controls
- 1.6L
System OK

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Friday, July 31, 2009 1:07:02 PMPage 18 © 2005 Mitchell Repair Information Company, LLC.

The control module turns OFF the MIL after 3 consecutive ignition cycles that the diagnostic runs and
does not fail.
A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other
emission related diagnostic.
Clear the MIL and the DTC with a scan tool.
Diagnostic Aids
Use the Freeze Frame and/or Failure Records data in order to locate an intermittent condition. If you
cannot duplicate the DTC, the information included in the Freeze Frame and/or Failure Records data may
aid in determining the number of miles since the DTC set. The Fail Counter and Pass Counter can also aid
in determining the number of ignition cycles that the diagnostic reported a pass and/or fail. Operate the
vehicle within the same freeze frame conditions (RPM, engine load, vehicle speed, temperature, etc.).
This will isolate when the DTC failed.
Refer to the following:
Intermittent Conditions
in Engine Controls - 1.6L (L91)
Test Description
The number below refers to the step number on the diagnostic table.
2: This step determines if the fault is present.
DTC P0462
StepActionValueYesNo
Schematic Reference: Instrument Cluster Schematics
Connector End View Reference: Instrument Panel, Gages, and Console Connector End Views

1
Did you perform the Diagnostic System Check -
Instrument Cluster?
-
Go to Step 2
Go to
Diagnostic
System Check
- Instrument
Cluster
2
1. Turn ON the ignition, with the engine
OFF.
2. Observe the Fuel Level Sensor voltage
parameter with a scan tool.
Is the voltage more than the specified value?
4.25 V
Go to Step 4 Go to Step 3
1. Observe the Freeze Frame/Failure Records
for this DTC.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.

2005 Chevrolet Aveo
2005 ACCESSORIES & EQUIPMENT Instrument Panel, Gages, & Console - Aveo
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Friday, July 31, 2009 1:07:02 PMPage 19 © 2005 Mitchell Repair Information Company, LLC.

3
4. Operate the vehicle within the Conditions
for Running the DTC. You may also
operate the vehicle within the conditions
that you observed from the Freeze
Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 4
Go to
Diagnostic Aids
4
1. Turn OFF the ignition.
2. Disconnect the fuel level sensor through
the access panel under the rear seat.
3. Turn ON the ignition, with the engine
OFF.
4. Observe the Fuel Level Sensor voltage
parameter with a scan tool.
Is the voltage less than the specified value?
4.25 V
Go to Step 6 Go to Step 5
5
Test the signal circuit of the fuel level sensor for
a short to ground. Refer to Circuit Testing
and
Wiring Repairs
in Wiring Systems.
Did you find and correct the condition?-
Go to Step 10 Go to Step 7
6
Test for shorted terminals and poor connections
at the fuel level sensor. Refer to Testing for
Intermittent Conditions and Poor
Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?-
Go to Step 10 Go to Step 8
7
Test for shorted terminals and poor connections
at the engine control module (ECM). Refer to
Testing for Intermittent Conditions and Poor
Connections and Connector Repairs in Wiring
Systems.
Did you find and correct the condition?-
Go to Step 10 Go to Step 9
8
Replace the fuel sender assembly. Refer to the
following:
Fuel Sender Assembly Replacement
in Engine
Controls - 1.6L (L91)

Did you complete the replacement?-
Go to Step 10
-
9
Replace the control module. Refer to the
following:
Engine Control Module (ECM) Replacement

in Engine Controls - 1.6L (L91)
--

2005 Chevrolet Aveo
2005 ACCESSORIES & EQUIPMENT Instrument Panel, Gages, & Console - Aveo
Microsoft
Friday, July 31, 2009 1:07:02 PMPage 20 © 2005 Mitchell Repair Information Company, LLC.

DTC P0463
Circuit Description
The fuel level sensor changes resistance based on fuel level. The fuel level sensor has a signal circuit and a
ground circuit. The engine control module (ECM) applies 5 volts on the signal circuit to the sensor. The ECM
monitors the changes in this voltage caused by changes in the resistance of the sensor in order to determine fuel
level.
When the fuel tank is full, the sensor resistance is low, and the ECM signal voltage is high. When the fuel tank
is empty, the sensor resistance is high, and the signal voltage is low.
The ECM uses inputs from the fuel level sensor in order to calculate the total fuel percentage remaining in the
fuel tank. The ECM uses the fuel level information for the evaporative emission (EVAP) and misfire
diagnostics. The fuel level information is sent to the instrument panel cluster (IPC).
If the ECM detects a signal voltage higher than the operating range of the sensor, this DTC sets.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P0463 Fuel Level Sensor Circuit High Voltage
Conditions for Running the DTC

Did you complete the replacement?
Go to Step 10
10
1. Clear the DTCs with a scan tool.
2. Turn OFF the ignition for 30 seconds.
3. Start the engine.
4. Operate the vehicle within the Conditions
for Running the DTC. You may also
operate the vehicle within the conditions
that you observed from the Freeze
Frame/Failure Records.
Did the DTC fail this ignition?
-
Go to Step 2 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 in
Engine Controls
- 1.6L
System OK

2005 Chevrolet Aveo
2005 ACCESSORIES & EQUIPMENT Instrument Panel, Gages, & Console - Aveo
Microsoft
Friday, July 31, 2009 1:07:02 PMPage 21 © 2005 Mitchell Repair Information Company, LLC.