Engine Controls - 1.6l (l91) - DTC p0106 to DTC p0172 Chevrolet Aveo I

Circuit Description

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The ECM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the ECM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The ECM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The ECM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the engine is operated at WOT. The MAP sensor contains the following circuits

1. A 5-volt reference
2. A low reference
3. A MAP sensor signal

If the ECM detects the MAP sensor signal is not within the predicted range this DTC sets.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0106 Manifold Absolute Pressure (MAP) Sensor Performance

Condition for Running the DTC

1. DTCs P0107, P0108, P0115, P0117, P0118, P0122, P0123, P0125, P0201, P0202, P0203, P0204, P0300, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0506, P0507 are not set.
2. The engine is running.
3. Valid barometric pressure (BARO) update.
4. The traction control is not active.
5. The torque converter clutch (TCC) is steady (A/T).
6. The A/C compressor clutch is steady.
7. The coolant temperature is more than -10 C (14 F).
8. The engine speed is between 1,300-4,500 RPM.
9. The change in engine speed is less than 200 RPM.
10. The change in idle air is less than 5 percent.
11. The change in throttle position (TP) is less than 3 percent, or the change in MAP is less than 5 percent.
12. The change in exhaust gas recirculation (EGR) position is less than 6 percent.
13. The above conditions are stabilized for 1.5 seconds.
14. DTC P0106 runs continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects that the actual MAP signal is not within the predicted range for more than 25 seconds.

Action Taken When the DTC Sets

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

Conditions for Clearing the MIL/DTC

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Test Description

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

1. 8: While starting the engine, the MAP sensor should detect any changes in manifold pressure. This test is to determine if the sensor is stuck at a value.
2. 9: A normal MAP sensor will react as quickly to the throttle changes. A MAP sensor should not appear to be "lazy" or catch up with the throttle movements.

DTC P0106

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The ECM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the ECM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The ECM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The ECM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the TP sensor is more than 28 percent. The MAP sensor contains the following circuits

1. A 5-volt reference
2. A low reference
3. A MAP sensor signal

If the ECM detects that the MAP sensor pressure/voltage is too low, DTC P0107 sets.

This diagnostic procedure supports the following DTC

DTC P0107 Manifold Absolute Pressure (MAP) Sensor Circuit Low Voltage

Conditions for Running the DTC

1. DTCs P0122, P0123, P1121, P1122 are not set.
2. The TP sensor is more than or equal to 0 percent if the engine speed is less than or equal 1,000 RPM or the TP sensor is more than 5 percent if the engine speed is more than 1,000 RPM.
3. The ignition 1 voltage is more than 11.5 volts.
4. DTC P0107 runs continuously once the above conditions are met.

The ECM detects that the MAP is less than 12 kPa for more than 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

Diagnostic Aids

1. If a shared 5-volt reference circuit is shorted to ground or shorted to a voltage, the other 5-volt reference circuits may be affected.
2. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0107

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The engine control module (ECM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The ECM provides a ground on the low reference circuit. The MAP sensor provides a signal to the ECM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The ECM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The ECM should detect a high signal voltage at a high MAP, such as the ignition is ON, with the engine OFF, or at a wide open throttle (WOT). The MAP sensor is also used to determine the barometric pressure (BARO). This occurs when the ignition switch is turned ON, with the engine OFF. The BARO reading may also be updated whenever the TP sensor is more than 28 percent. The MAP sensor contains the following circuits

1. A 5-volt reference
2. A low reference
3. A MAP sensor signal

If the ECM detects that the MAP sensor pressure/voltage is excessively high, DTC P0108 sets.

This diagnostic procedure supports the following DTC

DTC P0108 Manifold Absolute Pressure (MAP) Sensor Circuit High Voltage

1. DTCs P0122, P0123, P1121, and P1122 are not set.
2. The engine is running for more than 10 seconds.
3. The TP sensor is less than 15 percent if the engine speed is less than 2,500 RPM or the TP sensor is less than 35 percent if the engine speed is more than 2,500 RPM.
4. DTC P0108 runs continuously once the above conditions are met.

The ECM detects that the MAP is more than 103 kPa for more than 5 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. 4: This step determines if there is a short to voltage or an open condition in the circuits.

1. 9: This step determines if the circuit has a short to voltage. A short to voltage can cause more than 1 DTC to set.

DTC P0108

The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. The ECM performs two test to determine if the IAT is stuck in range. The ECM performs the following tests

Start-up Test

The ECM stores the intake air temperature from the previous ignition cycle. The ECM then compares the IAT from the previous ignition cycle to the start-up IAT on the next ignition cycle. If the ECM does not detect a difference between the previous ignition cycle IAT and the start-up IAT, this DTC sets. If the diagnostic does not immediately pass, a delay timer increments. If the delay timer exceeds a threshold, the Start-up test is complete and the ECM will perform the Idle/Cruise test.

Idle/Cruise Test

The ECM monitors the intake air temperature at an idle and at cruise. If intake air temperature does not change more than a predetermined amount after the Conditions for Running the DTC are met, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0110

This diagnostic procedure supports the following DTC

DTC P0110 Intake Air Temperature (IAT) Sensor Circuit

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0502, and P0562 are not set.
2. The engine is OFF for more than 8 hours.
3. The engine is operating. Idle Test The vehicle speed is less than 2 km/h (1.2 mph). The throttle position (TP) sensor is less than 2 percent. The engine is operating at idle. The above conditions are met for more than 60 seconds. Cruise Test The vehicle speed is more than 40 km/h (25 mph). The mass air flow (MAF) sensor is more than 15 g/s. The engine is operating at a cruise. The above conditions are met for more than 300 seconds.
4. DTC P0110 runs once an ignition cycle once the above conditions are met.

The ECM does not detect a difference of 3°C (5°F) between the previous ignition cycle intake air temperature (IAT) and the start-up intake air temperature (IAT) of the next ignition cycle.

Or

The ECM does not detect an intake air temperature (IAT) change of more than 3°C (5°F) for 2 seconds during the Idle/Cruise test.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. Test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
3. If the vehicle has set overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
4. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

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

1. 4: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.
2. 5: This step tests for excessive resistance in the IAT circuit.

DTC P0110

The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. If the ECM detects the difference between the start-up coolant temperature and the start-up intake air temperature is more than a predetermined amount, this DTC sets. This DTC also sets if the current intake air temperature is more than a predetermined amount based on the start-up engine coolant temperature.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0111

This diagnostic procedure supports the following DTC

DTC P0111 Intake Air Temperature (IAT) Sensor Performance

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0502, and P0562 are not set.
2. The engine is OFF for more than 8 hours.
3. The engine is operating. IAT Test 1 The start-up engine coolant temperature is more than -20°C (-4°F). The vehicle speed is more than 40 km/h (25 mph). The mass air flow (MAF) sensor is more than 15 g/s. The above conditions are met for more than 300 seconds. IAT Test 2 The vehicle speed is more than 40 km/h (25 mph). The mass air flow (MAF) sensor is more than 15 g/s. The above conditions are met for more than 300 seconds.
4. DTC P0111 runs once an ignition cycle once the above conditions are met.

The ECM detects a 20°C (36°F) difference between the start-up engine coolant temperature and the start-up intake air temperature for 2 seconds.

Or

The ECM detects that the current intake air temperature is more than a predetermined amount based on the start-up engine coolant temperature.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. Test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
3. If the vehicle has set overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
4. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

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

1. 4: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.
2. 5: This step tests for excessive resistance in the IAT circuit.

DTC P0111

The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. If the ECM detects an excessively low IAT signal voltage, which is a high temperature indication, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0112

This diagnostic procedure supports the following DTC

DTC P0112 Intake Air Temperature (IAT) Sensor Circuit Low Voltage

1. DTC P0502 is not set.
2. The engine run time is more than 120 seconds.
3. The vehicle speed is more than 50 km/h (31 mph).
4. This DTC runs continuously once the above conditions are met.

The ECM detects that the IAT sensor is more than 149°C (300°F) for more than 10 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
2. If the vehicle has set overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
3. A high resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may not set a DTC. Refer to «Circuit Testing»(/chevrolet/aveo/i-2003-2008/remont/electrical-component-locations/#wiring-systems-electrical-power-management__circuit-testing) in Wiring Systems.
4. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0112

The intake air temperature (IAT) sensor is a variable resistor that measures the temperature of the air entering the engine. The IAT sensor has a signal circuit and a low reference circuit. The engine control module (ECM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. If the ECM detects an excessively high IAT signal voltage, which is a low temperature indication, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0113

This diagnostic procedure supports the following DTC

DTC P0113 Intake Air Temperature (IAT) Sensor Circuit High Voltage

1. DTCs P0117, P0118, and P0502 are not set.
2. The engine run time is more than 120 seconds.
3. The engine coolant temperature is more than 70°C (158°F).
4. The calculated air flow into the engine is less than 15 g/s.
5. The vehicle speed is less than 25 km/h (16 mph).
6. This DTC runs continuously once the above conditions are met.

The ECM detects that the IAT sensor parameter is less than -38°C (-36°F) for more than 4 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Test the IAT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
2. If the vehicle has set overnight, the IAT sensor and the ECT sensor values should display within 3°C (5°F).
3. A high resistance on either the IAT sensor signal circuit or the IAT sensor low reference circuit may not set a DTC. Refer to «Circuit Testing»(/chevrolet/aveo/i-2003-2008/remont/electrical-component-locations/#wiring-systems-electrical-power-management__circuit-testing) in Wiring Systems.
4. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0113

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects that the difference between the actual coolant temperature and the start-up coolant temperature is less than a threshold, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0115

This diagnostic procedure supports the following DTC

DTC P0115 Engine Coolant Temperature (ECT) Sensor Circuit

1. DTCs P0117, P0118, and P2610 are not set.
2. The engine has been OFF for more than 6 hours.
3. The engine is running.
4. This DTC runs once per ignition cycle once the above conditions are met.

The ECM detects that the difference between the actual ECT and the startup ECT is less than 3°C (5°F) for more than 2 minutes.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. After starting the engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
2. Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
3. Check for the correct operation of the engine cooling system and verify the correct coolant level.
4. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

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

1. 2: This step tests for excessive resistance in the ECT circuit.
2. 3: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same, test the signal circuit for a condition.

DTC P0115

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects an excessively low ECT signal voltage, which is a high temperature indication, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0117

This diagnostic procedure supports the following DTC

DTC P0117 Engine Coolant Temperature (ECT) Sensor Circuit Low Voltage

The engine is running for more than 120 seconds.

The ECM detects that the ECT sensor is more than 149°C (300°F) for more than 4 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. An overheating condition may cause this DTC to set.
2. After starting the engine, the ECT sensor temperature should rise steadily, then stabilize after the thermostat opens.
3. Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
4. If the vehicle has set overnight, the ECT sensor and the intake air temperature (IAT) sensor values should display within 3°C (5°F).
5. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0117

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The engine control module (ECM) supplies 5 volts to the ECT signal circuit and supplies a ground to the low reference circuit. If the ECM detects an excessively high ECT signal voltage, which is a low temperature indication, this DTC sets.

The following table illustrates the difference between temperature, resistance, and voltage

DTC P0118

This diagnostic procedure supports the following DTC

DTC P0118 Engine Coolant Temperature (ECT) Sensor Circuit High Voltage

The engine is running for more than 60 seconds.

The ECM detects that the ECT sensor is less than -39°C (-38°F) for more than 6 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Test the ECT sensor at various temperature levels in order to evaluate the possibility of a skewed sensor. A skewed sensor can result in a driveability condition.
2. If the vehicle has set overnight, the ECT sensor and the intake air temperature (IAT) sensor values should display within 3°C (5°F).
3. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0118

The throttle position (TP) sensor is used by the engine control module (ECM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with 3 circuits

1. A 5-volt reference circuit
2. A low reference circuit
3. A TP sensor signal circuit

The ECM provides the TP sensor with 5 volts on the 5-volt reference circuit, and a ground on the low reference circuit. The TP sensor provides a signal voltage that changes relative to throttle plate angle. The TP sensor signal voltage at idle is less than 0.5 volt. The TP sensor voltage is typically near 0.0 volts at idle, but could be as high as 0.5 volts. The TP sensor voltage should increase to above 4 volts at wide open throttle (WOT). If the ECM detects an excessively low signal voltage, DTC P0122 sets.

This diagnostic procedure supports the following DTC

DTC P0122 Throttle Position (TP) Sensor Circuit Low Voltage

1. The ignition is ON or the engine is running.
2. DTC P0122 runs continuously once the above condition is met.

The ECM detects that the TP sensor signal voltage is less than 0.14 volt for a total of 2.5 seconds during a 5 second period.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 3: If the DTC P0122 cannot be duplicated, the information included in the Freeze Frame data can be useful. Use the scan tool information to determine the status of the DTC. If the DTC occurs intermittently, using intermittent conditions may isolate the condition.
2. 4: This step determines if there is a short to ground or an open condition in the circuits.

DTC P0122

The throttle position (TP) sensor is used by the engine control module (ECM) to determine the throttle plate angle for various engine management systems. The TP sensor is a potentiometer type sensor with the following 3 circuits

1. A 5-volt reference
2. A low reference
3. A signal

The ECM provides the TP sensor with 5 volts on the 5-volt reference circuit, and a ground on the low reference circuit. The TP sensor provides a signal voltage that changes relative to throttle plate angle. The TP sensor signal voltage at idle is less than 0.5 volt. The TP sensor voltage is typically near 0.0 volts at idle, but could be as high as 0.5 volts. The TP sensor voltage should increase to above 4 volts at wide open throttle (WOT). If the ECM detects an excessively high signal voltage, DTC P0123 sets.

This diagnostic procedure supports the following DTC

DTC P0123 Throttle Position (TP) Sensor Circuit High Voltage

1. The ignition is ON or the engine is running.
2. DTC P0123 runs continuously once the above conditions are met.

The ECM detects that the TP sensor signal voltage is more than 4.9 volts for a total of 2.5 seconds during a 5 second time period.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. 4: This step determines if there is a short to voltage or an open condition in the circuits.

1. 9: This step determines if the circuit has a short to voltage. A short to voltage can cause multiple DTCs to set.

DTC P0123

The engine control module (ECM) monitors the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The amount of air flow into an engine is proportional to the amount of heat an engine generates. The ECM monitors the amount of air flow into the engine to calculate engine coolant temperature (ECT). The ECM uses the calculated temperature to determine if the engine has warmed up to the closed loop temperature. If the coolant temperature does not increase normally or does not reach the closed loop temperature, diagnostics that use the ECT as enabling criteria, may not run when expected. If the engine coolant temperature fails to reach the closed loop temperature, before a predetermined amount of air flow enters the engine, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0125 Engine Coolant Temperature (ECT) Insufficient for Closed Loop Fuel Control

1. DTCs P0117, P0118, P0122, P0123, P0502, P0562, P0563, P0606, and U0101 are not set.
2. The engine is operating.
3. The start-up engine coolant temperature is more than 34°C (93°F).
4. Before the ECM can report DTC P0125 failed, the engine must be idling for 10-600 seconds which is based off of start-up coolant temperature.
5. Before the ECM can report DTC P0125 failed, the airflow into the engine must be between 100-8,000 g/s which is based off of start-up coolant temperature.
6. DTC P0125 runs once an ignition cycle once the above conditions are met.

The ECM detects the actual ECT difference of 0.3-51°C (32.5-124°F) of the calculated ECT for a time of 100-600 seconds, which the amount of time depends on the start-up coolant temperature.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

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

1. 5: This step tests for excessive resistance in the ECT circuit.
2. 6: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.

DTC P0125

The engine control module (ECM) monitors the temperature of the engine coolant for engine control and as an enabling criteria for some diagnostics. The amount of air flow into an engine is proportional to the amount of heat an engine generates. The ECM monitors the amount of air flow into the engine to calculate engine coolant temperature (ECT). The ECM uses the calculated temperature to determine if the engine has warmed up to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach regulating temperature of the thermostat, diagnostics that use the ECT as enabling criteria, may not run when expected. If the engine coolant temperature fails to reach the thermostat regulating temperature, before a predetermined amount of air flow enters the engine, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0128 Engine Coolant Temperature (ECT) Below Thermostat Regulating Temperature

1. DTCs P0117, P0118, P0122, P0123, P0502, P0562, P0563, P0606, and U0101 are not set.
2. The engine is operating.
3. The start-up intake air temperature is more than -39°C (-38°F).
4. Before the ECM can report DTC P0128 failed, the engine must be idling for more than a predetermined amount of time which is based off of start-up coolant temperature.
5. Before the ECM can report DTC P0128 failed, the airflow into the engine must be more than a predetermined amount which is based off of start-up coolant temperature.
6. DTC P0128 runs once an ignition cycle once the above conditions are met.

The ECM detects a 20°C (68°F) difference between the ECT sensor and the thermostat regulated temperature.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. Use the J 35616 Connector Test Adapter Kit for any test that requires probing the ECM harness connector or a component harness connector.
2. For an intermittent condition, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

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

1. 5: This step tests for excessive resistance in the ECT circuit.
2. 6: This step isolates the condition. If the temperature changes, test for a condition in the low reference circuit. If the temperature remains the same test the signal circuit for a condition.

DTC P0128

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of approximately 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

If the ECM detects the HO2S 1 voltage is too low, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0131 HO2S Circuit Low Voltage Sensor 1

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The fuel system is in closed loop.
5. DTC P0131 runs continuously once the above conditions are met for 3 seconds.

The ECM detects that the HO2S 1 voltage is less than 50 mV for 25 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0131

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of approximately 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

If the ECM detects the HO2S 1 voltage is too high, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0132 HO2S Circuit High Voltage Sensor 1

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The fuel system is in closed loop.
5. DTC P0132 runs continuously once the above conditions are met for 3 seconds.

The ECM detects that the HO2S 1 voltage is more than 952 mV for 25 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0132

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of approximately 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

The ECM monitors the rich-to-lean and lean-to-rich transition time. A transition is defined as the HO2S voltage changes from above 600 mV to below 300 mV or from below 300 mV to above 600 mV. If the ECM detects that the transition time is too long, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0133 HO2S Slow Response Sensor 1

1. DTCs P0106, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0134, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, P0507, P2195, and P2196 are not set.
2. The engine coolant temperature is more than 70°C (158°F).
3. The ignition 1 voltage is more than 10 volts.
4. The fuel system is in closed loop.
5. The engine run time is more than 60 seconds.
6. The engine speed is between 1,500-3,000 RPM.
7. The calculated air flow is between 9-30 g/s.
8. The EVAP purge is less than 20 percent.
9. DTC P0133 runs once per ignition cycle once the above conditions are met for 2 seconds.

The ECM detects that the HO2S 1 rich-to-lean average response time is less than 90 milliseconds or lean-to-rich average response time is more than 125 milliseconds.

Or

The ECM detects that the HO2S 1 rich-to-lean or lean-to-rich switches are less than 10.

Or

The ECM detects that the HO2S 1 signal spends twice the amount of time in the rich region as compared to the lean region or the HO2S 1 signal spends twice the amount of time in the lean region as compared to the rich region.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 2: This step determines if the condition is present. This test may take 5-10 minutes for the diagnostic to run.
2. 4: An exhaust leak 6-12 inches away from the HO2S can cause a DTC to set.
3. 5: Certain RTV silicone gasket materials release vapors that can contaminate the HO2S. Silicone in the fuel can also cause silicone contamination. If the sensors appear contaminated by silicone, and if all the silicone sealant is a non-silicone base, advise the customer to try a different fuel company. A missing fuel filler restrictor indicates that the customer may have used leaded fuel.

DTC P0133

The heated oxygen sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the control module operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. The control module supplies the HO2S with a reference, or bias voltage of approximately 450 mV. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0-1,000 mV. This voltage will fluctuate above and below the bias voltage. Once sufficient HO2S voltage fluctuation is observed by the control module, Closed Loop is entered. The control module uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases above bias voltage toward 1,000 mV indicates a rich fuel mixture. An HO2S voltage that decreases below bias voltage toward 0 mV indicates a lean fuel mixture.

The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the control module to calculate the air-to-fuel ratio sooner.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

If the ECM detects that the HO2S voltage remains within the bias voltage range, DTC P0134 will set.

This diagnostic procedure supports the following DTC

DTC P0134 HO2S Circuit Insufficient Activity Sensor 1

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The fuel system is in closed loop.
5. The calculated airflow is more than 9 g/s.
6. The engine run time is more than 60 seconds.
7. DTC P0134 runs continuously once the above conditions are met for 2 seconds.

The ECM detects that the HO2S 1 voltage is between 300-600 mV for 10 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 4: This step tests for a short to voltage to the signal circuit of the HO2S 1.
2. 5: This step tests the HO2S 1 signal and the low reference circuit for an open. The HO2S voltage should go low.

DTC P0134

The heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. Ground is provided to the heater on the low control circuit by a low side driver within the control module. The control module monitors the current draw of the heater to determine if a failure is present.

If the ECM detects that the HO2S 1 heater current is below a specified value, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0135 HO2S Heater Performance Sensor 1

1. DTCs P0106, P0107, P0117, and P0118 are not set.
2. The engine run time is more than 3 minutes.
3. The ignition 1 voltage is more than 10 volts.
4. The manifold absolute pressure (MAP) is less than 65 kPa.
5. DTC P0135 runs continuously once the above conditions are met.

The ECM detects that the HO2S 1 heater current is less than 0.1 amps for 3 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 6: This step is testing the heater control circuit for a short to ground.
2. 7: This step is testing the heater control circuit for an open or for a short to voltage.
3. 8: This step is testing the heater control circuit for high resistance. If the voltage is more than the specified value, test the circuit for high resistance.

DTC P0135

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.

The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period and determines if the majority of the samples are out of the operating range.

The ECM monitors the HO2S voltage for being fixed below a predetermined voltage. If the ECM detects the voltage is too low, this DTC sets.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

This diagnostic procedure supports the following DTC

DTC P0137 HO2S Circuit Low Voltage Sensor 2

Closed Loop Test

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0141, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The calculated airflow is more than 9 g/s.
5. The fuel system is in closed loop.
6. DTC P0137 runs continuously once the above conditions are met for 3 seconds.

Power Enrichment Test

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0141, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The air fuel ratio is less than or equal to 13.5:1.
5. DTC P0137 runs continuously once the above conditions are met for 3 seconds.

Closed Loop Test

1. The ECM detects that the HO2S 2 voltage is less than 52 mV.
2. The condition exists for more than 4 minutes.

Power Enrichment Test

1. The ECM detects that the HO2S 2 voltage is less than 35 mV during power enrichment.
2. The condition exists for more than 11 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0137

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.

The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period and determines if the majority of the samples are out of the operating range.

The ECM monitors the HO2S voltage for being fixed below a predetermined voltage. If the ECM detects the voltage is too high, this DTC sets.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

This diagnostic procedure supports the following DTC

DTC P0138 HO2S Circuit High Voltage Sensor 2

Closed Loop Test

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0141, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The calculated airflow is more than 9 g/s.
5. The fuel system is in closed loop.
6. DTC P0138 runs continuously once the above conditions are met for 3 seconds.

Decel Fuel Cut-Off (DFCO) Test

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0141, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. DTC P0138 runs continuously once the above conditions are met for 3 seconds.

Closed Loop Test

1. The ECM detects that the HO2S 2 voltage is more than 952 mV.
2. The condition exists for more than 4 minutes.

Decel Fuel Cut-Off (DFCO) Test

1. The ECM detects that the HO2S 2 voltage is more than 550 mV during deceleration.
2. The condition exists for more than 11 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

DTC P0138

The engine control module (ECM) supplies a voltage near 450 mV between the heated oxygen sensor (HO2S) high signal circuit and the low reference circuit. The HO2S varies the voltage over a range from about 1,000 mV when the exhaust is rich, down through about 10 mV when the exhaust is lean.

The ECM monitors and stores the HO2S voltage information. The ECM evaluates the HO2S voltage samples in order to determine the amount of time that the HO2S voltage was out of range. The ECM compares the stored HO2S voltage samples taken within each sample period and determines if the majority of the samples are out of the operating range.

The ECM monitors the HO2S voltage for being fixed below a predetermined voltage. If the ECM detects that the HO2S voltage remains within the bias voltage range, this DTC sets.

The HO2S utilizes the following circuits

1. A signal circuit
2. A low reference circuit
3. An ignition 1 voltage circuit
4. A heater control circuit

This diagnostic procedure supports the following DTC

DTC P0140 HO2S Circuit Insufficient Activity Sensor 2

1. DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0141, P0171, P0172, P0201-P0204, P0300, P0336, P0337, P0351, P0352, P0401, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P0506, and P0507 are not set.
2. The engine coolant temperature is more than 60°C (140°F).
3. The ignition 1 voltage is more than 10 volts.
4. The fuel system is in closed loop.
5. The calculated airflow is more than 9 g/s.
6. The engine run time is more than 60 seconds.
7. DTC P0140 runs continuously once the above conditions are met for 3 seconds.

The ECM detects that the HO2S 2 voltage is between 422-478 mV for 3 minutes.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 4: This step tests for a short to voltage to the signal circuit of the HO2S 2.
2. 5: This step tests the HO2S 2 signal and the low reference circuit for an open. The HO2S voltage should go low.

DTC P0140

The heated oxygen sensors (HO2S) are used for fuel control and post catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content in the exhaust stream. The HO2S must reach operating temperature to provide an accurate voltage signal. A heating element inside the HO2S minimizes the time required for the sensor to reach operating temperature. Voltage is provided to the heater by the ignition 1 voltage circuit through a fuse. Ground is provided to the heater on the low control circuit by a low side driver within the control module. The control module monitors the current draw of the heater to determine if a failure is present.

If the ECM detects that the HO2S 2 heater current is below a specified value, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0141 HO2S Heater Performance Sensor 2

1. The engine run time is more than 1 minute.
2. The ignition 1 voltage is more than 10 volts.
3. DTC P0141 runs continuously once the above conditions are met.

The ECM detects that the HO2S 2 heater current is less than 0.1 amps for 13 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

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

1. 6: This step is testing the heater control circuit for a short to ground.
2. 7: This step is testing the heater control circuit for an open or for a short to voltage.
3. 8: This step is testing the heater control circuit for high resistance. If the voltage is more than the specified value, test the circuit for high resistance.

DTC P0141

The engine control module (ECM) controls a Closed Loop air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The ECM monitors the heated oxygen sensor (HO2S) signal voltage and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The long term fuel trim values change in response to trends in the short term fuel trim. The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. The ideal fuel trim values are around 0 percent. A positive fuel trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition. The fuel trim cells are based on the engine speed and load. If the ECM detects an excessively lean condition, the ECM sets DTC P0171.

This diagnostic procedure supports the following DTC

DTC P0171 Fuel Trim System Lean

1. DTCs P0106, P0107, P0108, P0112, P0113, P0115, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0201, P0202, P0203, P0204, P0217, P0300, P0336, P0337, P0341, P0342, P0351, P0352, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0506, P0507, P2195, and P2196 are not set.
2. The engine coolant temperature (ECT) is between 70°C (158°F) and 115°C (239°F).
3. The barometric pressure is more than 72 kPa.
4. The calculated air flow is between 1.5 g/s and 45 g/s.
5. The manifold absolute pressure (MAP) sensor is between 25 kPa and 99.7 kPa.
6. The intake air temperature (IAT) is between -40°C (-40°F) and 120°C (248°F).
7. The engine speed is between 700 RPM and 6,000 RPM.
8. The throttle position (TP) sensor angle is less than 95 percent.
9. The vehicle speed is less than 140 km/h (87 mph).
10. The fuel system is operating in Closed Loop.
11. The ignition 1 voltage is more than 11 volts.
12. DTC P0171 runs continuously once the above conditions are met.

The average long term fuel trim cell values are more than 30 percent for 10 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. The system will become lean if a fuel injector is not supplying enough fuel.
2. A lean condition could be present during high fuel demand due to a fuel pump that does not deliver enough fuel, a plugged fuel filter, or a restricted fuel pipe.
3. Test for fuel contamination. Water or alcohol can effect fuel trim. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool)»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool)»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis) .
4. Review the Failure Records with a scan tool. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0171

The engine control module (ECM) controls a Closed Loop air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. The ECM monitors the heated oxygen sensor (HO2S) signal voltage and adjusts the fuel delivery based on the signal voltage while in Closed Loop. A change made to the fuel delivery changes the long and short term fuel trim values. The short term fuel trim values change rapidly in response to the HO2S signal voltages. These changes fine tune the engine fueling. The long term fuel trim values change in response to trends in the short term fuel trim. The long term fuel trim makes coarse adjustments to fueling in order to re-center and restore control to short term fuel trim. The ideal fuel trim values are around 0 percent. A positive fuel trim value indicates that the ECM is adding fuel in order to compensate for a lean condition. A negative fuel trim value indicates that the ECM is reducing the amount of fuel in order to compensate for a rich condition. The fuel trim cells are based on the engine speed and load. If the ECM detects an excessively rich condition, the ECM sets DTC P0172.

This diagnostic procedure supports the following DTC

DTC P0172 Fuel Trim System Rich

1. DTCs P0106, P0107, P0108, P0112, P0113, P0115, P0117, P0118, P0122, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0201, P0202, P0203, P0204, P0217, P0300, P0336, P0337, P0341, P0342, P0351, P0352, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0506, P0507, P2195, and P2196 are not set.
2. The engine coolant temperature (ECT) is between 70°C (158°F) and 115°C (239°F).
3. The barometric pressure is more than 72 kPa.
4. The calculated air flow is between 1.5 g/s and 45 g/s.
5. The manifold absolute pressure (MAP) sensor is between 25 kPa and 99.7 kPa.
6. The intake air temperature (IAT) is between -40°C (-40°F) and 120°C (248°F).
7. The engine speed is between 700 RPM and 6,000 RPM.
8. The throttle position (TP) sensor angle is less than 95 percent.
9. The vehicle speed is less than 140 km/h (87 mph).
10. The fuel system is operating in Closed Loop.
11. The ignition 1 voltage is more than 11 volts.
12. DTC P0172 runs continuously once the above conditions are met.

The average long term fuel trim cell values are more than -30 percent for 10 seconds.

1. The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic 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.

1. The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
2. A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
3. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
4. Clear the MIL and the DTC with a scan tool.

1. The system will become rich if a fuel injector is supplying too much fuel.
2. Test for fuel contamination. Water or alcohol can effect fuel trim. Refer to «Alcohol/Contaminants-in-Fuel Diagnosis (W/O Special Tool)»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis) or «Alcohol/Contaminants-in-Fuel Diagnosis (W/Special Tool)»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis) .
3. Review the Failure Records with a scan tool. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0172

See also:
• Engine Controls Schematics
• Engine Controls Connector End Views
• Diagnostic System Check - Engine Controls
• Intermittent Conditions
• Restricted Exhaust
• Circuit Testing
• Using Connector Test Adapters
• Measuring Voltage Drop
• Wiring Repairs
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Diagnostic Trouble Code (DTC) List
• Using Fused Jumper Wires
• Loss of Coolant
• Thermostat Diagnosis
• Fuel Injector Balance Test with Special Tool
• Symptoms - Engine Exhaust
• Repairing Connector Terminals
• DTC P0106