Engine Controls - 1.6l (l91) - DTC p0456 to DTC p2196 Chevrolet Aveo I

Circuit Description

The evaporative emission (EVAP) small leak test applies vacuum to the EVAP system and monitors vacuum decay. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the EVAP canister purge valve and the EVAP vent valve are turned ON. This allows the engine to draw vacuum on the EVAP system. After the desired vacuum level has been achieved, the EVAP purge valve is turned OFF, sealing the system. A leak is detected by monitoring for a decrease in the vacuum level during a given time period. If the system detects a leak larger than a calibrated amount, DTC P0456 will set.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0456 Evaporative Emissions (EVAP) Very Small Leak Detected

Conditions for Running the DTC

1. Before the engine control module (ECM) can report DTC P0456 failed, DTC P0441 must run and pass.
2. DTCs P0106, P0107, P0108, P112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0133, P0134, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204 P0402, P0404, P0405, P0406, P0443, P0452, P0453, P0462, P0463, P0488, P0502, P2195, and P2196 are not set.
3. The ignition 1 voltage is between 11-16 volts.
4. The barometric pressure (BARO) is more than 72 kPa.
5. The engine coolant temperature (ECT) and the intake air temperature (IAT) at start-up are between -5°C and +40°C (+23°F and +140°F).
6. The engine is OFF for more than 6 hours or the following conditions must be met: The start-up IAT minus start-up ECT are within 12°C (22°F). The start-up ECT minus start-up IAT is within 50°C (90°F).
7. The start-up IAT minus IAT are within 3°C (5°F).
8. The purge enable time is less than 360 seconds.
9. The engine run time is more than 1 second and less than 360 seconds.
10. The fuel level is between 24-94 percent.
11. The engine speed is less than 1,200 RPM.
12. The vehicle speed is less than 3 km/h (2 mph).
13. The throttle position is less than 1 percent.
14. DTC P0456 runs once an ignition cycle when the above conditions are met.

Conditions for Setting the DTC

The EVAP system can achieve vacuum but a vacuum decay is detected during the diagnostic test.

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.

Diagnostic Aids

To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. See Special Tools . Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light. See Special Tools . Introducing smoke in 15-second intervals will allow less pressure into the EVAP system. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.

Test Description

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

1. 6: This step verifies that repairs are complete and that other conditions are not present.

DTC P0456

The engine control module (ECM) monitors the position of the exhaust gas recirculation (EGR) valve through the EGR valve position sensor. The EGR valve position sensor sends a feedback voltage on the signal circuit to the ECM. This voltage varies depending on the position of the EGR valve. The ECM interprets this voltage as the position of the EGR valve. When the ignition switch is turned ON, the ECM records the minimum value of the EGR valve position sensor which is the learned closed position. If the ECM detects a difference between the actual closed EGR position and the learned closed position of the EGR valve, DTC P0488 sets.

This diagnostic procedure supports the following DTC

DTC P0488 Exhaust Gas Recirculation (EGR) Closed Position Performance

1. DTCs P0112, P0113, P0405, P0406, and P0502 are not set.
2. The ambient air temperature is more than 3°C (37°F).
3. The engine is running.
4. The desired EGR position is 0 percent.
5. The ignition voltage is between 11.7-16 volts.
6. DTC P0488 runs continuously once the above conditions are met.

1. The ECM detects a difference of more than 10 percent between the actual and the learned position of the EGR valve.
2. The ECM detects this failure for 40 consecutive times out of 40 test samples.
3. The above failure must fail 3 sets of the 40 test samples. Each set of test samples are separated by more than 5 seconds with the desired EGR position being more than 30 percent.

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.

DTC P0488

System Description

This DTC tests for continuous intake manifold vacuum flow to the Evaporative Emission (EVAP) System. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Closed. The control module monitors the fuel tank pressure (FTP) sensor to determine if a vacuum is being drawn on the EVAP system. If vacuum in the EVAP system is more than a predetermined value within a predetermined time, this DTC sets.

The following table illustrates the relationship between the ON and OFF states, and the Open or Closed states of the EVAP canister purge and vent solenoid valves.

DTC P0496

This diagnostic procedure supports the following DTC

DTC P0496 Evaporative Emissions (EVAP) System Continuous Purge Flow

1. DTCs P0106, P0107, P0108, P112, P0113, P0117, P0118, P0122, P0123, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0201, P0202, P0203, P0204, P0300, P0402, P0404, P0405, P0406, P0443, P0452, P0453, P0462, P0463, P0488, P0502, P0506, P0507, P2195, and P2196 are not set.
2. The ignition 1 voltage is between 11-16 volts.
3. The barometric pressure (BARO) is more than 72 kPa.
4. The engine run time is more than 1 second and less than 120 seconds.
5. The engine coolant temperature (ECT) and the intake air temperature (IAT) at start-up are between -5°C and +40°C (23°F and 140°F).
6. The start-up IAT minus the startup ECT is within 12°C (22°F).
7. The start-up ECT minus startup IAT is within 50°C (90°F).
8. The start-up IAT minus IAT are within 3°C (5°F).
9. DTC P0496 runs once an ignition cycle when the above conditions are met.

The FTP sensor indicates vacuum during a non-purge condition.

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 EVAP system tests run when engine is first started and meets The Conditions for Running the DTC. An intermittent condition could be caused by an improperly installed or damaged EVAP canister purge solenoid valve, or by a temporary blockage or restriction in the EVAP canister purge solenoid valve.

DTC P0496

The vehicle speed information is provided to the engine control module (ECM) by the vehicle speed sensor (VSS). The VSS is a permanent magnet generator that is mounted to the transmission and produces a pulsing voltage. The AC voltage amplitude and frequency increases with vehicle speed. The ECM converts the pulsing voltage into km/h (mph). The ECM supplies the VSS signal to the following components

1. The instrument panel for speedometer and odometer operation
2. The cruise control module
3. The multi-function alarm module

If the ECM detects no vehicle speed for a calibrated amount of time, this DTC sets.

This diagnostic supports the following DTC

DTC P0502 Vehicle Speed Sensor (VSS) Circuit Low Voltage

1. DTCs P0106, P0107, P0108, P0115, P0117, P0118, P0122, P0123, P0125, P0128, P0201, P0202, P0203, P0204, P0217, P0300, P0351, P0352, P0402, P0404, P0405, P0406, and P0488 are not set.
2. The engine is running.
3. The engine coolant temperature (ECT) is more than 60°C (140°F).
4. The ignition 1 voltage is between 11-16 volts.
5. The following are additional Conditions for Running for the applicable test: Power Test The engine speed is between 1,200-4,000 RPM. The throttle position (TP) sensor is between 25-60 percent. The manifold absolute pressure (MAP) is more than 60 kPa. Deceleration Test The MAP is less than 30 kPa. The change in engine speed per cycle is less than or equal to 50 RPM/cycle. The throttle position (TP) sensor is less than or equal to 0.8 percent. The engine speed is between 1,800-6,000.
6. DTC P0502 runs continuously when the above conditions are met.

The ECM detects that the vehicle speed is less than 5 km/h (3.1 mph) for more than 35 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. An intermittent condition may be caused by a poor connection, rubbed-through wire insulation, or a wire that is broken inside the insulation.
2. Ensure the VSS is correctly torqued to the transmission housing.

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

1. 2: The permanent magnet generator only produces a signal if the drive wheels are turning greater than 8 km/h (5 mph). This step determines if DTC P0502 is the result of a hard failure or an intermittent condition.

DTC P0502

The engine control module (ECM) controls the engine idle speed by adjusting the position of the idle air control (IAC) valve pintle. The IAC valve is a stepper motor driven by two internal coils. The movement of the IAC valve is controlled electrically by four circuits. Drivers within the ECM control the polarity of the two windings inside the IAC valve through these circuits. The ECM, by commanding the correct polarity in sequence, is able to command the motor within the IAC valve to rotate clockwise or counter clockwise in steps. In order for the armature of the stepper motor of the IAC valve to turn one revolution, it needs to move approximately twenty four steps. The IAC valve motor is linked by a gear drive to the IAC valve pintle. The electrical pulses sent to the IAC valve coils, by the ECM, allows the pintle to extend or retract into the passage in the throttle body. By retracting the pintle, air is allowed to bypass the throttle valve, which will increase air flow and raise engine speed. When the pintle is extended, bypass air is decreased which lowers engine speed. IAC valve movement is measured in counts on the scan tool. Each count is equivalent to a step of the IAC valve. When the IAC valve is fully extended, and seated in the throttle body bore, the scan tool displays zero and the engine speed is slow. As the IAC valve pintle retracts the counts will raise along with engine speed.

If the ECM detects that the engine speed is not within a predetermined amount of the desired engine speed, a diagnostic trouble code (DTC) sets.

IAC Valve Reset

When the ignition switch is turned OFF for more than ten seconds an IAC valve reset occurs. At that time, the ECM commands the IAC valve to extend for a certain period which allows the IAC pintle to seat in the throttle body bore. This position is then sensed as zero count position for the IAC valve by the ECM. It must be observed that the IAC valve position is only sensed by the ECM measuring counts or steps of the driver circuit, there is no direct sensing of its exact position. When this extend time period ends, the ECM then commands the IAC valve to retract a predetermined amount. This will allow for a high engine speed on the next ignition cycle. If for any reason the IAC valve pintle moves after this reset, before the next ignition cycle, the ECM will not be able to detect it and will affect the ability to control engine idle. When the IAC valve is removed for any reason the reset must be performed.

This diagnostic procedure supports the following DTCs

1. DTC P0506 Idle Speed Low
2. DTC P0507 Idle Speed High

1. DTCs P0106, P0107, P0108, P0112, P0113, P0115, P0117, P0118, P0121, P0123, P0125, P0128, P0131, P0132, P0133, P0134, P0135, P0141, P0171, P0172, P0201, P0202, P0203, P0204, P0300, P0336, P0337, P0341, P0342, P0351, P0352, P0402, P0404, P0405, P0406, P0441, P0443, P0488, P0502, P2195, and P2196 are not set.
2. The engine coolant temperature (ECT) is more than 60°C (140°F).
3. The intake air temperature is more than -20°C (-4°F)
4. The barometric pressure (BARO) is more than 72 kPa.
5. The engine run time is more than 60 seconds.
6. The manifold absolute pressure (MAP) is less than 60 kPa - P0506 only.
7. The manifold absolute pressure (MAP) is more than 22 kPa - P0507 only.
8. The ignition voltage is between 11.0 and 16.0 volts.
9. This DTC runs continuously when the above conditions are met for 5 seconds.

DTC P0506

1. The actual engine speed is 100 RPM less than the desired engine speed.
2. The condition exists for 10 seconds.

DTC P0507

1. The actual engine speed is 200 RPM more than the desired engine speed.
2. The condition exists 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. A low, high or unstable idle condition may be caused by a non-IAC system condition that cannot be overcome by the IAC valve. Refer to «Rough, Unstable, or Incorrect Idle and Stalling»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__rough-unstable-or-incorrect-idle-and) .
2. If the condition is intermittent, refer to «Intermittent Conditions»(/chevrolet/aveo/i-2003-2008/remont/testing-diagnostics/#engine-controls-16l-l91-troubleshooting-diagnosis__intermittent-conditions) .

DTC P0506 or P0507

This diagnostic applies to internal microprocessor integrity conditions within the engine control module (ECM). This diagnostic also addresses if the ECM is not programmed.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0601 Control Module Read Only Memory (ROM)
2. DTC P0602 Control Module Not Programmed
3. DTC P0606 Control Module Internal Performance
4. DTC P2610 Control Module Ignition Off Timer Performance

DTC P0601

1. The ignition is ON, with the engine OFF.
2. DTC P0601 runs once an ignition cycle.

DTC P0602

1. The ignition is ON, with the engine OFF.
2. DTC P0602 runs once an ignition cycle.

DTC P0606

1. The ignition is ON, with the engine OFF.
2. The ignition 1 voltage is more than 11 volts.
3. DTC P0606 runs continuously with ignition ON or engine operating.

DTC P2610

1. The ignition is ON, with the engine OFF.
2. The non-volatile memory has not reset.
3. DTC P2610 runs once an ignition cycle.

DTC P0601

The ECM detects that the checksum calculation does not match the expected checksum.

DTC P0602

The ECM detects that programming is incomplete for more than 1 second.

DTC P0606

The ECM detects an internal condition for more than 3 seconds.

DTC P2610

The ECM detects a low power counter error for more than 3 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 4 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: A DTC P0602 indicates the ECM is not programmed.
2. 4: Attempt to program the ECM. If the ECM fails to program a second time, replace the ECM.

DTC P0601, P0602, P0606, or P2610

An ignition 1 voltage is supplied directly to the intake manifold tuning (IMT) valve solenoid or variable geometry induction system (VGIS). The control module controls the IMT solenoid by grounding the control circuit via an internal driver switch. The primary function of the driver is to supply ground for the controlled component. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, DTC P0660 sets.

This diagnostic procedure supports the following DTC

DTC P0660 Intake Manifold Tuning (IMT) Valve Solenoid Control Circuit

1. The engine is operating.
2. The ignition 1 voltage is more 10 volts.
3. DTC P0660 runs continuously once the above conditions are met.

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for more than 10 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

Conditions for Clearing the DTC

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 2: A click should be heard or felt when the valve operates. Ensure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
2. 5: This step verifies that the ECM is providing ground to the IMT solenoid.
3. 6: This step tests if the IMT solenoid control circuit is grounded.

DTC P0660

This diagnostic trouble code (DTC) indicates that an emission related transmission DTC set in the transmission control module (TCM). The engine control module (ECM) receives the TCM DTC information over the serial data circuit. The ECM turns ON the malfunction indicator lamp (MIL) when the TCM sends a message over the serial data circuit requesting MIL illumination. The ECM will also store the freeze frame/failure records data for a transmission DTC. The DTC information for the ECM will only display DTC P0700, but the freeze frame/failure records data will display the transmission DTC that set.

This diagnostic procedure supports the following DTC

DTC P0700 Transmission Control Module (TCM) Requested MIL Illumination

DTC P0700 runs continuously

The ECM receives a serial data message, from the TCM, in order to illuminate the MIL.

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 P0700

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 that the MAP sensor pressure/voltage is intermittently high, DTC P1106 sets.

This diagnostic supports the following DTC

DTC P1106 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent 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.
4. The TP sensor is less than 35 percent if the engine speed is more than 2,500 RPM.
5. DTC P1106 runs continuously once the above conditions are met.

The ECM detects that the MAP sensor is more than 103 kPa intermittently for more than 60 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 3: This step attempts to determine if the intermittent fault is a connector.

1. 4: This step attempts to determine the location of the intermittent fault.

DTC P1106

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 that the MAP sensor pressure/voltage is intermittently too low, DTC P1107 sets.

This diagnostic procedure supports the following DTC

DTC P1107 Manifold Absolute Pressure (MAP) Sensor Circuit Intermittent Low Voltage

1. DTCs P0122, P0123, P1121, and 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 to 1,000 RPM.
3. The TP sensor is more than 5 percent if the engine speed is more than 1,000 RPM.
4. The ignition 1 voltage is more than 11.5 volts.
5. DTC P1107 runs continuously once the above conditions are met.

The ECM detects that the MAP sensor is less than 12 kPa intermittently for more than 60 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 3: This step attempts to determine if the intermittent fault is a connector.

1. 4: This step attempts to determine the location of the intermittent fault.

DTC P1107

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 intermittent 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 P1111

This diagnostic supports the following DTC

DTC P1111 Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage

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

1. The ECM detects that the intake air temperature (IAT) is less than -38°C (-36°F) intermittently.
2. The condition exists for more than 3 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear 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. 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 P1111

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 intermittent 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 P1112

This diagnostic supports the following DTC

DTC P1112 Intake Air Temperature (IAT) Sensor Circuit Intermittent Low Voltage

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

1. The ECM detects that the intake air temperature (IAT) is more than 149°C (300°F) intermittently.
2. The condition exists for more than 20 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear 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 IAT sensor and the ECT 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 P1112

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 intermittent 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 P1114

This diagnostic supports the following DTC

DTC P1114 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent Low Voltage

1. The engine run time is more than 120 seconds.
2. This DTC runs continuously when the above condition is met.

The ECM detects that the engine coolant temperature is more than 149°C (300°F) intermittently.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear 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 P1114

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 intermittent 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 P1115

This diagnostic supports the following DTC

DTC P1115 Engine Coolant Temperature (ECT) Sensor Circuit Intermittent High Voltage

1. The engine run time is more than 120 seconds.
2. This DTC runs continuously once the above condition is met.

The ECM detects that the engine coolant temperature is less than -38°C (-36°F) intermittently.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear 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 P1115

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 three 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. Rotation of the TP sensor rotor from the closed throttle position to the wide open throttle (WOT) position provides the ECM with a signal voltage from below 1 volt to greater than 4 volts through the TP sensor signal circuit. If the ECM detects an intermittent excessively high signal voltage, DTC P1121 sets.

This diagnostic procedure supports the following DTC

DTC P1121 Throttle Position (TP) Sensor Circuit Intermittent High Voltage

1. The ignition is ON.
2. DTC P1121 runs continuously once the above conditions are met for more than 2 seconds.

The ECM detects that the TP sensor voltage is intermittently greater than 4.9 volts for more than 2 seconds during a 60 second time period.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

Inspect for the following conditions

1. The ECM harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection
2. The wiring harness for damage-If the harness appears OK, observe the throttle position display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the fault.

If DTC P1121 cannot be duplicated, reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

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

1. 7: This test will determine an intermittent faulty TP sensor utilizing the MIN MAX 100 millisecond capture mode on the DMM.

DTC P1121

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 three 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. Rotation of the TP sensor rotor from the closed throttle position to the wide open throttle (WOT) position provides the ECM with a signal voltage from below 1 volt to greater than 4 volts through the TP sensor signal circuit. If the ECM detects an intermittent excessively low signal voltage, DTC P1122 sets.

This diagnostic procedure supports the following DTC

DTC P1122 Throttle Position (TP) Sensor Circuit Intermittent Low Voltage

1. The ignition is ON.
2. DTC P1122 runs continuously once the above conditions are met for more than 2 seconds.

The ECM detects that the TP sensor voltage is intermittently less than 0.14 volt for a total of 2 seconds during a 60 second time period.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

Inspect for the following conditions

1. The ECM harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection
2. The wiring harness for damage-If the harness appears OK, observe the throttle position display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the display will indicate the location of the fault.

If DTC P1122 cannot be duplicated, reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition occurs that caused the DTC to set. This may assist in diagnosing the condition.

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

1. 6: This test will determine an intermittent faulty TP sensor utilizing the MIN MAX 100 millisecond capture mode on the DMM.

DTC P1122

The engine control module (ECM) detects engine misfire events by monitoring variations in the crankshaft rotation speed. Wheel speed changes caused by rough road conditions can cause changes in crankshaft speed. By monitoring the wheel speed sensors, the anti-lock brake system (ABS) can determine if the vehicle is operating on a rough road. If the ABS is detecting a rough road condition severe enough to affect misfire detection, a rough road signal is sent to the ECM on the serial data circuit. If DTC P0300 is set and the rough road information is not available due to an ABS malfunction, DTC P1380 will set.

This diagnostic procedure supports the following DTC

DTC P1380 Misfire Detected - Rough Road Data Not Available

1. The engine is operating for more than 10 seconds.
2. DTC P1380 runs continuously once the above condition is met.

1. The ECM does not receive rough road detection data from the EBCM for more than 2 seconds.
2. The above condition is met for 2 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

DTC P1380

The engine control module (ECM) detects engine misfire events by monitoring variations in the crankshaft rotation speed. Wheel speed changes caused by rough road conditions can cause changes in crankshaft speed. By monitoring the wheel speed sensors, the anti-lock brake system (ABS) can determine if the vehicle is operating on a rough road. If the ABS is detecting a rough road condition severe enough to affect misfire detection, a rough road signal is sent to the ECM on the serial data circuit. If DTC P0300 is set and the rough road information is not available due to an ABS malfunction, DTC P1381 sets.

This diagnostic procedure supports the following DTC

DTC P1381 Misfire Detected - No Communication With Brake Control Module

1. The engine is operating for more than 10 seconds.
2. DTC P1381 runs continuously once the above condition is met.

1. A serial data malfunction exists preventing the ECM from receiving rough road detection data.
2. The above condition is met for 2 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 1: This step will diagnose a malfunction in the serial data circuits.

DTC P1381

The rough road sensor is a vertical low G-acceleration sensor. By sensing vertical acceleration caused by rough road conditions, the engine control module (ECM) can determine if the changes in crankshaft speed are due to engine misfire or are driveline induced. If the rough road sensor detects a rough road condition, the ECM misfire detection diagnostic will be de-activated. The rough road sensor at rest output should be between 2.30-2.65 volts. During a rough road condition, the voltage output can vary between 0.5 volts and 4.5 volts. The rough road sensor is a capacitive type sensor with 3 circuits

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

The ECM provides the rough road sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Vibration to the rough road sensor from rough road conditions in the road, provides the ECM with a signal voltage from less than 1 volt to more than 4 volts. If the ECM detects that the rough road sensor input is not within a calibrated limit of the estimated value, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P1391 Rough Road Sensor Performance

1. The engine is running.
2. The vehicle speed is less than 5 km/h (3.1 mph). OR
3. The engine is running.
4. The vehicle speed is between 30-70 km/h (19-43 mph).
5. DTC P1391 runs continuously once the above conditions are met.

The ECM detects that the rough road sensor output is not within range for more than 22.5 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 2: The rough road sensor will give correct voltages only if it is level and mounted securely to its bracket.
2. 12: This step tests for poor connection at the ECM or the harness connections for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and a poor terminal-to-wire connection.

DTC P1391

The rough road sensor is a vertical low G-acceleration sensor. By sensing vertical acceleration caused by rough road conditions, the engine control module (ECM) can determine if the changes in crankshaft speed are due to engine misfire or are driveline induced. If the rough road sensor detects a rough road condition, the ECM misfire detection diagnostic will be de-activated. The rough road sensor at rest output should be between 2.30-2.65 volts. During a rough road condition, the voltage output can vary between 0.5 volts and 4.5 volts. The rough road sensor is a capacitive type sensor with 3 circuits

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

The ECM provides the rough road sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Vibration to the rough road sensor from rough road conditions in the road, provides the ECM with a signal voltage from less than 1 volt to more than 4 volts. If the ECM detects an excessively low signal voltage, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P1392 Rough Road Sensor Circuit Low Voltage

1. The engine is running.
2. DTC P1392 runs continuously once the above condition is met for more than 10 seconds.

The ECM detects that the rough road sensor voltage is less than 0.10 volts for more than 10 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 2: The rough road sensor will give correct voltages only if it is level and mounted securely to its bracket.

DTC P1392

The rough road sensor is a vertical low G-acceleration sensor. By sensing vertical acceleration caused by rough road conditions, the engine control module (ECM) can determine if the changes in crankshaft speed are due to engine misfire or are driveline induced. If the rough road sensor detects a rough road condition, the ECM misfire detection diagnostic will be de-activated. The rough road sensor at rest output should be between 2.30-2.65 volts. During a rough road condition, the voltage output can vary between 0.5 volts and 4.5 volts. The rough road sensor is a capacitive type sensor with 3 circuits

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

The ECM provides the rough road sensor with 5 volts on the 5-volt reference circuit and a ground on the low reference circuit. Vibration to the rough road sensor from rough road conditions in the road, provides the ECM with a signal voltage from less than 1 volt to more than 4 volts. If the ECM detects an excessively high signal voltage, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P1393 Rough Road Sensor Circuit High Voltage

1. The engine is running.
2. DTC P1393 runs continuously once the above condition is met for more than 10 seconds.

The ECM detects that the rough road sensor output is more than 4.90 volts for more than 10 seconds.

1. The control module stores the DTC information into memory when the diagnostic runs and fails.
2. The malfunction indicator lamp (MIL) will not illuminate.
3. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Failure Records.
4. The driver information center, if equipped, may display a message.

1. A current DTC Last Test Failed clears when the diagnostic runs and passes.
2. A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
3. Clear the DTC with a scan tool.

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

1. 2: The rough road sensor will give correct voltages only if it is level and mounted securely to its bracket.

DTC P1393

Modules that are connected to the shared communication circuits monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. The modules have pre-recorded information about what messages are needed to be exchanged on the serial data circuits for each virtual network. The messages are usually supervised and some periodic messages are used by the receiver module as an availability indication of the transmitter module.

This diagnostic procedure supports the following DTC

DTC P1626 Lost Communication With Theft Deterrent Control Module

Conditions for Running the DTCs

1. The ignition is ON and the engine is cranking.
2. The DTC P1626 diagnostic runs once per drive cycle.

The ECM cannot communicate with the theft deterrent control module

1. The DTC P1626 is stored in the ECM.
2. Engine control system functions are disabled and the engine will not start.

1. A current DTC clears when the malfunction is no longer present.
2. A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
3. The scan tool can clear the DTC from the module memory.

1. An open or a short in the serial data circuits of the theft deterrent control module can cause a DTC P1626 to set. The serial data circuit fault will also cause the following conditions: The theft deterrent status will switch to Enable and the engine will crank but not start. If there is open circuit, the scan tool will not communicate with the ECM, but will continue to communicate with the TCM. If there is a short circuit, the scan tool will not communicate with either the ECM or the TCM. The DTC P1626 will be stored in memory and is displayed by the scan tool when communication with the ECM resumes.
2. An intermittent electrical condition in the theft deterrent system can cause this code to set. Refer to «Testing for Intermittent Conditions and Poor Connections»(/chevrolet/aveo/i-2003-2008/remont/electrical-component-locations/#wiring-systems-electrical-power-management__testing-for-intermittent-conditions-and-poor) in Wiring Systems.

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

1. 3: This step tests for ignition voltage to the theft deterrent module. The theft deterrent module cannot communicate with the ECM if there is no ignition positive voltage.
2. 4: This step tests for a good ground to the theft deterrent module. The theft deterrent module cannot communicate with the ECM if there is no ground circuit.

DTC P1626

The engine control module (ECM) initiates engine operation based on the immobilizer password received from the vehicle immobilizer, or vehicle theft deterrent (VTD) control module. The ignition key head contains a transponder that emits a magnetic field. This magnetic field interacts with the magnetic field generated by the coils of the theft deterrent control module creating a voltage. This voltage signal becomes the immobilizer password that is sent to the ECM. If the password is incorrect, or cannot be read by the ECM, DTC P1631 is set.

This diagnostic procedure supports the following DTC

DTC P1631 Invalid Data Received From Vehicle Immobilizer Control Module

1. The ignition is ON and the engine is cranking.
2. The DTC P1631 diagnostic runs once per drive cycle.

The ECM has received invalid data from the VTD control module

1. The DTC P1631 is stored in the ECM.
2. Engine control system functions are disabled and the engine will not start.

1. A current DTC clears when the malfunction is no longer present.
2. A history DTC clears when the module ignition cycle counter reaches the reset threshold, without a repeat of the malfunction.
3. The scan tool can clear the DTC from the module memory.

Attempting to start the vehicle by bypassing the VTD system or by substituting parts without performing the Programming Theft Deterrent System Components procedure will continue to cause a no start condition.

DTC P1631

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 vehicle 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 signal is too low during Power Enrichment (PE) mode, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2195 HO2S Circuit Low Voltage During Power Enrichment 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 air fuel ratio is less than or equal to 13.5:1.
5. The engine is in Power Enrichment (PE) mode.
6. DTC P2195 runs continuously once the above conditions are met for 2 seconds.

The ECM detects that the HO2S 1 voltage is less than 350 mV for 11 seconds during Power Enrichment (PE) mode.

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 P2195

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 vehicle 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 signal is too high during Decel Fuel Cut-Off (DFCO) mode, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P2196 HO2S Circuit High Voltage During Decel Fuel Cut-Off (DFCO) 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 ignition 1 voltage is more than 10 volts.
3. The engine is in Decel Fuel Cut-Off (DFCO) mode.
4. DTC P2196 runs continuously once the above conditions are met for 3 seconds.

The ECM detects that the HO2S 1 voltage is more than 550 mV for 11 seconds during Decel Fuel Cut-Off (DFCO) mode.

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 P2196

See also:
• Special Tools
• Evaporative Emissions (EVAP) Hose Routing Diagram
• Diagnostic System Check - Engine Controls
• Diagnostic Trouble Code (DTC) List
• Lifting and Jacking the Vehicle
• Engine Controls Connector End Views
• Intermittent Conditions
• Circuit Testing
• Wiring Repairs
• Testing for Intermittent Conditions and Poor Connections
• Repairing Connector Terminals
• Connector Repairs
• Rough, Unstable, or Incorrect Idle and Stalling
• Testing for Short to Ground
• Diagnostic System Check - Automatic Transmission
• DTC P0108
• Inducing Intermittent Fault Conditions
• Testing for Electrical Intermittents
• Probing Electrical Connectors
• Diagnostic System Check - ABS
• Theft Deterrent System Schematics
• Symptoms - Data Link Communications
• Symptoms - Engine Exhaust
• Fuel System Diagnosis