Engine Controls - 8.1L - Diagnostics (Dtcs P0030-P0174): Diagnosis GMC Sierra 1500

Circuit Description

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. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the engine control module (ECM).

The ECM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The ECM monitors the voltage on the HO2S heater low control circuit for heater fault diagnosis. If the ECM detects that the HO2S heater low control circuit voltage is not within a specified range, DTC P0030 sets for HO2S bank 1 sensor 1, DTC P0036 sets for HO2S bank 1 sensor 2, DTC P0050 sets for HO2S bank 2 sensor 1, or DTC P0056 sets for HO2S bank 2 sensor 2.

DTC Descriptors

This diagnostic procedure supports the following DTCs

1. DTC P0030 HO2S Heater Control Circuit Bank 1 Sensor 1
2. DTC P0036 HO2S Heater Control Circuit Bank 1 Sensor 2
3. DTC P0050 HO2S Heater Control Circuit Bank 2 Sensor 1
4. DTC P0056 HO2S Heater Control Circuit Bank 2 Sensor 2

Conditions for Running the DTC

1. The Ignition 1 Signal parameter is between 10-18 volts.
2. This diagnostic runs continuously when the above condition is met.

Conditions for Setting the DTC

The ECM detects that the affected HO2S heater low control circuit is not within a specified range for 6 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.

The heated oxygen sensor (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. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the powertrain control module (PCM). The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The PCM determines the temperature by measuring the current flow through the heater. When the heater is in the ON state, the PCM will pulse the heater OFF for a duration of 50 ms, once per second. The PCM calculates the heater resistance on a cold start. This diagnostic will only run once per ignition cycle. If the PCM detects that the heater calculated resistance is not within the expected range, the following DTCs will set

1. DTC P0053 for HO2S Bank 1 Sensor 1
2. DTC P0054 for HO2S Bank 1 Sensor 2
3. DTC P0059 for HO2S Bank 2 Sensor 1
4. DTC P0060 for HO2S Bank 2 Sensor 2

This diagnostic procedure supports the following DTCs

1. DTC P0053 HO2S Heater Resistance Bank 1 Sensor 1
2. DTC P0054 HO2S Heater Resistance Bank 1 Sensor 2
3. DTC P0059 HO2S Heater Resistance Bank 2 Sensor 1
4. DTC P0060 HO2S Heater Resistance Bank 2 Sensor 2

1. DTCs P0112, P0113, P0116, P0117, P0118, P0128, P2610 are not set.
2. The ignition is OFF for more than 10 hours.
3. The Engine Coolant Temperature (ECT) Sensor parameter is between -30 and +45°C (-22 and +113°F) at engine start-up.
4. The ECT Sensor parameter minus the IAT Sensor parameter is less than 8°C (14°F) at engine start-up.
5. The engine is started.
6. This diagnostic runs one time per valid cold start once the above conditions are met.

The PCM detects that the affected HO2S heater calculated resistance is not within an expected range at engine start-up for 1 second.

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 powertrain control module (PCM) uses the following readings in order to calculate the predicted mass air flow (MAF) rate

1. The throttle position (TP)
2. The barometric (BARO) pressure
3. The intake air temperature (IAT)
4. The engine revolutions per minute (RPM)

The PCM compares the predicted MAF value to the actual MAF value, and to the speed density calculation in order to verify the proper throttle operation.

DTC Descriptor

This diagnostic procedure supports the following DTC

DTC P0068 Throttle Body Air Flow Performance

1. DTCs P0601, P0602, P0604, P0606, P1516, P2101, P2108 or U0107 are not set.
2. DTCs P0120 and P0220 are not active at the same time.
3. The engine operates longer than 1 second.
4. The engine speed is greater than 500 RPM.
5. This diagnostic runs continuously when the above conditions are met.

1. The PCM detects that the difference between the actual MAF and the speed density calculated air flow is greater than expected.
2. All of the above conditions met for less than 1 second.

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 and/or the Failure Records.
3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
4. A message center or an indicator displays Reduced Engine Power.
5. Under certain conditions the control module commands the engine OFF.

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. Inspect the throttle blade for being broken, bent, or missing.
2. Inspect the TP sensor for proper installation. A sensor that is mis-aligned could set this DTC.
3. Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
4. Physically and visually inspect the throttle body assembly and correct any problems that you observe. Manually move the throttle blade from closed to wide open throttle (WOT). You should not need to use excess force. The throttle blade should move smoothly through the full range and then should independently return to a slightly open position.
5. When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Remember this if you review the stored information in Capture Info.
6. For an intermittent condition, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits

1. An ignition 1 voltage circuit
2. A ground circuit
3. A signal circuit

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load. The PCM uses the following sensor inputs to calculate a predicted MAF value

1. The manifold absolute pressure (MAP) sensor
2. The intake air temperature (IAT) sensor
3. The engine speed revolutions per minute (RPM)

The PCM compares the actual MAF sensor frequency signal to the predicted MAF value. This comparison will determine if the signal is stuck based on a lack of variation, or is too low or too high for a given operating condition. If the PCM detects the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value DTC P0101 sets.

This diagnostic procedure supports the following DTC

DTC P0101 Mass Air Flow (MAF) Sensor Performance

1. DTCs P0068, P0102, P0103, P0106, P0107, P0108, P0120, P0220, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P2135 are not set.
2. The engine is cranking or running.
3. The ignition 1 signal is between 11-18 volts.
4. The throttle position (TP) indicated angle is less than 95 percent.
5. The change in the TP indicated angle is less than 5 percent.
6. The MAP sensor is less than 80 kPa.
7. The change in the MAP sensor is less than 3 kPa.
8. The above conditions are met for 1.5 seconds.
9. DTC P0101 runs continuously when the above conditions are met.

The PCM detects that the actual MAF sensor frequency signal is not within a predetermined range of the calculated MAF value for more than 4 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. Inspect the harness of the MAF sensor to verify that it is not routed too close to the following components: The secondary ignition wires or coils Any solenoids Any relays Any motors
2. A low minimum air rate through the sensor bore at idle or during deceleration may cause this DTC to set. Inspect for any vacuum leak downstream of the MAF sensor.
3. Inspect for any contamination or debris on the sensing elements of the MAF sensor.
4. Inspect the air induction system for any water intrusion. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.
5. A wide open throttle acceleration from a stop should cause the MAF Sensor parameter on the scan tool to increase rapidly. This increase should be from 7-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
6. A high resistance of 15 ohms or more on the ignition 1 voltage circuit may cause this DTC to set. A high resistance may cause a driveability concern before this DTC sets.
7. The barometric pressure (BARO) that is used to calculate the predicted mass air flow value is initially based on the MAP sensor at key ON. When the engine is running, the BARO value is continually updated near wide open throttle. A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate and may result in a no start condition. The value shown for the MAP Sensor parameter varies with the altitude. With the ignition ON and the engine OFF, 101 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 305 meters (1,000 feet) of altitude.
8. A high resistance on the 5-volt reference circuit of the MAP sensor may cause this DTC to set.
9. A high resistance on the low reference circuit of the MAP sensor may cause this DTC to set.
10. If the condition is intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

The mass air flow (MAF) sensor is an airflow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal in order to provide the correct fuel delivery for a wide range of engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits

1. An ignition 1 voltage circuit
2. A ground circuit
3. A signal circuit

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage in order to produce a frequency based on inlet air flow through the sensor bore. The frequency varies within a range of around 2,000 Hertz at idle to about 10,000 Hertz at maximum engine load. If the PCM detects a frequency signal lower than the possible range of a properly operating MAF sensor, DTC P0102 sets.

This diagnostic procedure supports the following DTC

DTC P0102 Mass Air Flow (MAF) Sensor Circuit Low Frequency

1. The engine is running for more than 2 seconds.
2. The engine speed is more than 400 RPM.
3. The ignition 1 signal is more than 8 volts.
4. The above conditions are met for more than 1 second.
5. DTC P0102 runs continuously when the above conditions are met.

The PCM detects that the MAF sensor frequency signal is less than 1,200 Hertz for more than 0.6 second.

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.

Inspect for the following conditions

1. An incorrectly routed harness-Inspect the harness of the MAF sensor in order to verify that it is not routed too close to the following components: The secondary ignition wires or coils Any solenoids Any relays Any motors Any aftermarket accessories - Refer to «Checking Aftermarket Accessories»(ref-238178-S36192588272006072400000) .
2. A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any vacuum leaks downstream of the MAF sensor.
3. A wide open throttle (WOT) acceleration from a stop should cause the MAF Sensor g/s parameter on the scan tool to increase rapidly. This increase should be from 6-12 g/s at idle to 230 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.
4. A resistance of 15 ohms or more on the ground circuit or the ignition 1 circuit of the MAF sensor can cause this DTC to set.

If the condition is intermittent, refer to Testing for Intermittent Conditions and Poor Connections .

The mass air flow (MAF) sensor is an air flow meter that measures the amount of air entering the engine. The powertrain control module (PCM) uses the MAF sensor signal to provide the correct fuel delivery for all engine speeds and loads. A small quantity of air entering the engine indicates a deceleration or idle condition. A large quantity of air entering the engine indicates an acceleration or high load condition. The MAF sensor has the following circuits

1. An ignition 1 voltage circuit
2. A ground circuit
3. A signal circuit

The PCM applies a voltage to the sensor on the signal circuit. The sensor uses the voltage to produce a frequency based on the inlet air flow through the sensor bore. The frequency varies within a range of near 2,000 Hertz at idle to near 10,000 Hertz at maximum engine load. If the PCM detects the frequency signal is more than the possible range of a correctly operating MAF sensor DTC P0103 sets.

This diagnostic procedure supports the following DTC

DTC P0103 Mass Air Flow (MAF) Sensor Circuit High Frequency

1. The engine is running for more than 2 seconds.
2. The engine speed is more than 400 RPM.
3. The ignition 1 signal is more than 8 volts.
4. The above conditions are met for more than 1 second.
5. DTC P0103 runs continuously when the above conditions are met.

The PCM detects that the MAF sensor frequency signal is more than 12,000 Hz.

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. Inspect the air induction system for any water intrusion. The water rapidly cools the hot sensing elements in the sensor causing a false indication of excessive air flow. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.
2. A poor connection in the ignition 1 voltage circuit of the MAF sensor may cause this DTC to set.
3. If the condition is intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

The manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM 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 in order 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 PCM monitors the MAP sensor signal for voltage outside of the normal range.

The PCM calculates a predicted value for the MAP sensor based on the throttle position (TP) and the engine speed. The PCM then compares the predicted value to the actual MAP sensor signal. If the PCM detects that the MAP sensor signal is not within the predicted range, DTC P0106 sets.

This diagnostic procedure supports the following DTC

DTC P0106 Manifold Absolute Pressure (MAP) Sensor Performance

1. DTCs P0068, P0107, P0108, P0120, P0220, P0506, P0507, P2135 are not set.
2. The engine is running.
3. The engine speed is between 500-5,000 RPM.
4. Any change in the engine speed is less than 125 RPM.
5. The change in air flow is less than 10 g/s.
6. The traction control is not active.
7. The A/C compressor clutch state does not change.
8. The power steering load is stable.
9. The brake switch state does not change.
10. The power take-off (PTO), if equipped, is not active.
11. The clutch switch state does not change, if equipped.
12. The above conditions are met for 1 second.
13. DTC P0106 runs continuously when the above conditions are met.

The PCM detects that the actual MAP sensor signal is not within the predicted range for 1.5 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 manifold absolute pressure (MAP) sensor responds to pressure changes in the intake manifold. The pressure changes occur based on the engine load. The MAP sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM 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 in order 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 PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that is excessively low, diagnostic trouble code (DTC) P0107 sets.

This diagnostic procedure supports the following DTC

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

1. DTC P0068, P0120, P0220, P2135 are not set.
2. The engine is running.
3. The throttle angle is more than 0 percent when the engine speed is less than 800 RPM. OR The throttle angle is more than 12.5 percent when the engine speed is more than 800 RPM.
4. DTC P0107 runs continuously when the above conditions are met.

The PCM detects that the MAP sensor voltage is less than 0.055 volt for more than 4 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.

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 MAP sensor has the following circuits

1. 5-volt reference circuit
2. Low reference circuit
3. MAP sensor signal circuit

The powertrain control module (PCM) supplies 5 volts to the MAP sensor on the 5-volt reference circuit. The PCM also provides a ground on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit which is relative to the pressure changes in the manifold. The PCM should detect a low signal voltage at a low MAP, such as during an idle or a deceleration. The PCM 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 in order 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 PCM monitors the MAP sensor signal for voltage outside of the normal range.

If the PCM detects a MAP sensor signal voltage that 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 P0068, P0120, P0220, P2135 are not set.
2. The engine has been running for a length of time that is determined by the startup coolant temperature. The length of time ranges from 10-242 seconds.
3. The accelerator pedal angle is less than 1 percent when the engine speed is less than 1,200 RPM. OR The throttle angle is less than 20 percent when the engine speed is more than 1,200 RPM.
4. DTC P0108 runs continuously when the above conditions are met.

The PCM detects that the MAP sensor voltage is more than 4.9 volts for more than 2 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.

DTC P0108

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively low IAT signal voltage, indicating a high temperature, DTC P0112 sets.

This diagnostic procedure supports the following DTC

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

1. DTCs P0116, P0117, P0118, P0128, P0502, P0503 are not set.
2. The engine run time is more than 45 seconds.
3. The vehicle speed sensor (VSS) indicates that the vehicle speed is more than 40 km/h (25 mph).
4. The engine coolant temperature (ECT) is less than 125°C (257°F).
5. DTC P0112 runs continuously when the above conditions are met.

The PCM detects that the IAT Sensor parameter is more than 128°C (262°F) for 12.5 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. When the vehicle is at ambient temperature the IAT sensor and the ECT sensor temperatures should be relatively close to each other. Refer to «Temperature vs Resistance»(ref-238194-S28420146912006072400000) .
2. If an intermittent condition is suspected, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

DTC P0112

The intake air temperature (IAT) sensor is a variable resistor. The IAT sensor has a signal circuit and a low reference circuit. The IAT sensor measures the temperature of the air entering the engine. The powertrain control module (PCM) supplies 5 volts to the IAT signal circuit and a ground for the IAT low reference circuit. When the IAT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the IAT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the IAT signal circuit. If the PCM detects an excessively high IAT signal voltage, indicating a low temperature, DTC P0113 sets.

This diagnostic procedure supports the following DTC

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

1. DTCs P0116, P0117, P0118, P0128, P0502, P0503 are not set.
2. The engine run time is more than 120 seconds.
3. The vehicle speed sensor (VSS) indicates that the vehicle speed is less than 11 km/h (7 mph).
4. The engine coolant temperature (ECT) is more than 60°C (140°F).
5. The mass air flow (MAF) is less than 15 g/s.
6. DTC P0113 runs continuously when the above conditions are met.

The PCM detects that the IAT Sensor parameter is less than -38°C (-36°F) for more than 12.5 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. When the vehicle is at ambient temperature the IAT sensor and the ECT sensor temperatures should be relatively close to each other. Refer to «Temperature vs Resistance»(ref-238194-S28420146912006072400000) .
2. If a short to a separate 5-volt source occurs this DTC may set.
3. If an intermittent condition is suspected, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

The engine coolant temperature (ECT) sensor is a variable resistor that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the signal circuit and a ground for the ECT low reference circuit. When the engine coolant temperature is low, the sensor resistance is high. When the engine coolant temperature is high, the sensor resistance is low. The PCM uses this High Side Coolant Rationality test to determine if the ECT input is skewed high. The internal clock of the PCM will record the amount of time the ignition is OFF. At restart the PCM will compare the temperature difference between the ECT and the intake air temperature (IAT). Before failing this test, the PCM will perform a calculation to determine the presence of an engine block heater. If the PCM detects that the temperature difference between the ECT and the IAT is not within the calibrated range after the ignition OFF time, DTC P0116 sets.

This diagnostic procedure supports the following DTC

DTC P0116 Engine Coolant Temperature (ECT) Sensor Performance

1. The ignition is ON.
2. DTCs P0112, P0113, P0117, P0118, P0128, P0502, P0503 are not set.
3. The IAT Sensor parameter is more than -7°C (20°F).
4. The vehicle has a minimum ignition OFF time of 10 hours.
5. DTC P0116 runs once per drive cycle when the above conditions are met.

The start-up ECT is more than the start-up IAT by 100°C (180°F).

OR

If the start-up ECT is more than the start-up IAT by 15°C (27°F), then the vehicle must be driven for more than 400 seconds over 24 km/h (15 mph). If the IAT sensor temperature decreases more than 8°C (14°F), a block heater is detected and the test is aborted. If the IAT sensor temperature does not decrease, a block heater was not detected and DTC P0116 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.

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 P0116 may set if the vehicle uses an aftermarket engine block heater.

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively low ECT signal voltage, which is a high temperature indication, DTC P0117 sets.

This diagnostic procedure supports the following DTC

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

1. The engine run time is more than 10 seconds. OR The engine run time is less than 10 seconds when the intake air temperature (IAT) is less than 50°C (122°F).
2. DTC P0117 runs continuously when the above condition is met.

The PCM detects that the ECT Sensor parameter is more than 138°C (280°F) for more than 23 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 overheating condition may cause this DTC to set.
2. If the condition is suspected of being an intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

DTC P0117

The engine coolant temperature (ECT) sensor is a variable resistor, that measures the temperature of the engine coolant. The ECT sensor has a signal circuit and a low reference circuit. The powertrain control module (PCM) supplies 5 volts to the ECT signal circuit and a ground for the ECT low reference circuit. When the ECT is cold, the sensor resistance is high. When the ECT increases, the sensor resistance decreases. With high sensor resistance, the PCM detects a high voltage on the ECT signal circuit. With lower sensor resistance, the PCM detects a lower voltage on the ECT signal circuit. If the PCM detects an excessively high ECT signal voltage, which is a low temperature indication, DTC P0118 sets.

This diagnostic procedure supports the following DTC

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

1. The engine has been running for more than 60 seconds. OR The engine run time is less than 60 seconds when the intake air temperature (IAT) is more than 0°C (32°F)
2. DTC P0118 runs continuously when the above condition is met.

The PCM detects that the ECT Sensor parameter is less than -38°C (-36°F) for 23 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. If a short to a separate 5-volt source occurs, this DTC may set.
2. If the condition is suspected of being intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

DTC P0118

The throttle position (TP) sensor 1 is a potentiometer type sensor with 3 circuits

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

The TP sensor is used to determine the throttle plate angle for various engine management systems. The control module provides the TP sensor a 5-volt reference circuit and a low reference circuit. The TP sensor then provides the control module a signal voltage proportional to throttle plate movement. TP sensor 1 signal voltage is low at closed throttle and increases as the throttle opens. When the control module detects that the TP sensor 1 signal or TP sensor 5-volt reference voltage is outside the predetermined range, this DTC sets.

This diagnostic procedure supports the following DTC

DTC P0120 Throttle Position (TP) Sensor 1 Circuit

1. DTCs U0107 or P2108 are not set.
2. The ignition switch is in the crank or run position.
3. The ignition voltage is more than 5.23 volts.
4. This diagnostic runs continuously when the above conditions are met.

1. The TP sensor 1 signal voltage is less than 0.37 volt or more than 4.51 volts.
2. The above condition is present for more than 1 second.

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 and/or the Failure Records.
3. The control module commands the TAC system to operate in the Reduced Engine Power mode.
4. A message center or an indicator displays Reduced Engine Power.
5. Under certain conditions the control module commands the engine OFF.

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. Inspect the throttle actuator control (TAC) module connectors for signs of water intrusion. When this occurs, multiple DTCs could be set with no circuit or component conditions found during diagnostic testing.
2. When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture info.
3. If this DTC is determined to be intermittent, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

An engine coolant temperature (ECT) sensor monitors the temperature of the coolant. This input is used by the powertrain control module (PCM) for engine control, and as an enabling criteria for some diagnostics.

The air flow coming into the engine is accumulated and used to determine if the vehicle has been driven within conditions that would allow the engine coolant to heat up normally to the thermostat regulating temperature. If the coolant temperature does not increase normally or does not reach the regulating temperature of the thermostat, diagnostics that use ECT as enabling criteria may not run when expected.

This DTC will only run once per ignition cycle within the enabling condition. If the PCM detects the calibrated amount of air flow and engine run time have been met and the ECT has not met the minimum thermostat regulating temperature, DTC P0128 sets.

This diagnostic procedure supports the following DTC

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

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0220, P0502, P0503, P2135 are not present.
2. The start-up ECT is less than 74°C (165°F) when the intake air temperature (IAT) is more than 10°C (50°F). OR The start-up ECT is less than 50°C (122°F) when the IAT is between -7 and +10°C (+19 and +50°F).
3. The fuel ethanol is less than 87 percent.
4. The IAT sensor parameter is between -7 and +55°C (+19 and +131°F).
5. The engine run time is between 120-1,370 seconds.
6. The vehicle speed is more than 8 km/h (5 mph) for more than 2.5 km (1.5 miles).
7. The mass air flow (MAF) is between 20-75 g/s with the average more than 10 g/s.
8. DTC P0128 runs one time per drive cycle when the above conditions are met.

The PCM detects all of the following conditions

1. The calibrated amount of engine run time has been met.
2. The calibrated amount of engine air flow has been met.
3. The calibrated vehicle speed and distance have been met.
4. The calibrated minimum ECT of 79°C (175°F) has not been met when the IAT is more than 10°C (50°F). OR The calibrated minimum ECT of 55°C (131°F) has not been met when the IAT is between -7 and +10°C (+19 and +50°F).

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 P0128

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the PCM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. If the PCM detects an HO2S voltage that stays below a specified value, DTC P0131 sets for HO2S bank 1 sensor 1, or DTC P0151 sets for HO2S bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1
2. DTC P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The Loop Status parameter is closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The TP Indicated Angle parameter is between 3-70 percent more than the value observed at idle.
6. The above conditions are met for 2 seconds.
7. This diagnostic runs continuously when the above conditions are met.

The PCM detects that the affected HO2S voltage parameter is less than 200 mV for 165 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.
3. The control module commands the Loop Status open.

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.

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the PCM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. If the PCM detects an HO2S voltage that stays above a specified value, DTC P0132 sets for HO2S bank 1 sensor 1, or DTC P0152 sets for HO2S bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0132 HO2S High Voltage Bank 1 Sensor 1
2. DTC P0152 HO2S High Voltage Bank 2 Sensor 1

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The Loop Status parameter is closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Tank Level Remaining parameter is more than 10 percent.
5. The TP Indicated Angle parameter is between 3-70 percent more than the value observed at idle.
6. The above conditions are met for 2 seconds.
7. This diagnostic runs continuously when the above conditions are met.

The PCM detects that the affected HO2S voltage parameter is more than 1050 mV for 48 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.
3. The control module commands the Loop Status open.

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.

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the PCM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. This diagnostic will only run once per ignition cycle. The PCM monitors the rich-to-lean and lean-to-rich transition time. A transition is defined as, the HO2S voltage changes from above 625 mV to below 250 mV or from below 250 mV to above 625 mV. If the PCM detects that the transition time is too long, DTC P0133 sets for HO2S bank 1 sensor 1 or DTC P0153 sets for HO2S bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0133 HO2S Slow Response Bank 1 Sensor 1
2. DTC P0153 HO2S Slow Response Bank 2 Sensor 1

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0131, P0132, P0134, P0135, P0151, P0152, P0154, P0155, P0200, P0220, P0300, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The ECT Sensor parameter is more than 60°C (140°F).
3. The EVAP Purge Solenoid Command parameter is more than 1 percent.
4. The MAF Sensor parameter is between 29-55 g/s.
5. The Engine Speed parameter is between 1,000-3,000 RPM.
6. The TP Indicated Angle parameter is 5 percent more than the value observed at idle.
7. The Loop Status parameter is closed.
8. The Ignition 1 Signal parameter is between 10-18 volts.
9. The Fuel Tank Level Remaining parameter is more than 10 percent.
10. The Engine Run Time parameter is more than 160 seconds.
11. The above conditions are met for 1 second.
12. This diagnostic runs continuously when the above conditions are met.

The PCM detects that the affected HO2S rich-to-lean or lean-to-rich average response time is more than a calibrated value for 100 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.

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the PCM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. If the PCM detects that the HO2S voltage remains within the bias voltage range, DTC P0134 sets for HO2S bank 1 sensor 1 or DTC P0154 sets for HO2S bank 2 sensor 1.

This diagnostic procedure supports the following DTCs

1. DTC P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor 1
2. DTC P0154 HO2S Circuit Insufficient Activity Bank 2 Sensor 1

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The Engine Run Time parameter is more than 300 seconds.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. This diagnostic runs continuously when the above conditions are met.

The PCM detects that the affected HO2S voltage parameter is between 350-550 mV for 60 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.
3. The control module commands the Loop Status open.

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 heated oxygen sensor (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. With the engine running, ground is provided to the heater by the HO2S heater low control circuit, through a low side driver within the powertrain control module (PCM). The PCM commands the heater ON or OFF to maintain a specific HO2S operating temperature range. The PCM determines the temperature by measuring the current flow through the heater. When the heater is in the ON state, the PCM will pulse the heater OFF for a duration of 50 ms, once per second. When the heater is in the OFF state, the PCM will pulse the heater ON for a duration of 50 ms, once per second. The PCM monitors the heater current with the engine running. This diagnostic will only run once per ignition cycle. If the PCM detects that the heater current is not within an expected range, the following DTCs will set

1. DTC P0135 for HO2S bank 1 sensor 1
2. DTC P0141 for HO2S bank 1 sensor 2
3. DTC P0155 for HO2S bank 2 sensor 1
4. DTC P0161 for HO2S bank 2 sensor 2

This diagnostic procedure supports the following DTCs

1. DTC P0135 HO2S Heater Performance Bank 1 Sensor 1
2. DTC P0141 HO2S Heater Performance Bank 1 Sensor 2
3. DTC P0155 HO2S Heater Performance Bank 2 Sensor 1
4. DTC P0161 HO2S Heater Performance Bank 2 Sensor 2

1. DTCs P0053, P0054, P0059, P0060, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The ECT Sensor parameter is more than 50°C (122°F).
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The MAF Sensor parameter is between 3-40 g/s.
5. The Engine Speed parameter is between 500-3,000 RPM.
6. The Engine Run Time parameter is more than 120 seconds.
7. The above conditions are met for 2 seconds.
8. This diagnostic runs 1 time per drive cycle when the above conditions are met.

1. The PCM detects that the affected HO2S Heater current parameter is more than 3.125 amps or less than 0.25 amps.
2. The above condition is met 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.

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the PCM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream. If the PCM detects an HO2S voltage that stays below a specified value, DTC P0137 sets for HO2S bank 1 sensor 2 or DTC P0157 sets for HO2S bank 2 sensor 2.

This diagnostic procedure supports the following DTCs

1. DTC P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
2. DTC P0157 HO2S Circuit Low Voltage Bank 2 Sensor 2

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0169, P0178, P0179, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The Loop Status parameter is closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Alcohol content parameter is less than 90 percent.
5. The Fuel Tank Level Remaining parameter is greater than 10 percent.
6. The TP Indicated Angle parameter is between 3-70 percent more than the value observed at idle.
7. The above conditions are met for 2 seconds.
8. This diagnostic runs continuously when the above conditions are met.

The PCM detects that the affected HO2S voltage parameter is less than 80 mV for 200 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.

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started, the PCM operates in Open Loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and Closed Loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream. Low HO2S voltage indicates a lean exhaust stream. If the PCM detects an HO2S voltage that stays above a specified value, DTC P0138 sets for HO2S bank 1 sensor 2 or DTC P0158 sets for HO2S bank 2 sensor 2.

This diagnostic procedure supports the following DTCs

1. DTC P0138 HO2S Circuit High Voltage Bank 1 Sensor 2
2. DTC P0158 HO2S Circuit High Voltage Bank 2 Sensor 2

1. DTCs P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0169, P0178, P0179, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The Loop Status parameter is closed.
3. The Ignition 1 Signal parameter is between 10-18 volts.
4. The Fuel Alcohol content parameter is less than 90 percent.
5. The Fuel Tank Level Remaining parameter is greater than 10 percent.
6. The TP Indicated Angle parameter is between 3-70 percent more than the value observed at idle.
7. The above conditions are met for 2 seconds.
8. This diagnostic runs continuously when the above conditions are met.

The PCM detects that the affected HO2S voltage parameter is greater than 950 mV for 200 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.

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. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature. The powertrain control module (PCM) supplies the HO2S with a reference, or bias, voltage of about 450 mV. When the engine is first started the PCM operates in open loop, ignoring the HO2S voltage signal. Once the HO2S reaches operating temperature and closed loop is achieved, the HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage. High HO2S voltage indicates a rich exhaust stream; low HO2S voltage indicates a lean exhaust stream. This diagnostic will only run once per ignition cycle. If the PCM detects that the HO2S voltage remains within the bias voltage range, DTC P0140 sets for HO2S bank 1 sensor 2 or DTC P0160 sets for HO2S bank 2 sensor 2.

This diagnostic procedure supports the following DTCs

1. DTC P0140 HO2S Circuit/Insufficient Activity Bank 1 Sensor 2
2. DTC P0160 HO2S Circuit/Insufficient Activity Bank 2 Sensor 2

1. DTCs P0054, P0060, P0068, P0101, P0102, P0103, P0106, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0120, P0128, P0141, P0161, P0200, P0220, P0442, P0446, P0452, P0453, P0455, P0496, P1125, P1258, P1516, P2101, P2108, P2135, U0107 are not set.
2. The Engine Run Time parameter is more than 300 seconds.
3. The Loop Status is closed.
4. The Ignition 1 Signal parameter is between 10-18 volts.
5. This diagnostic runs 1 time per drive cycle when the above conditions are met.

1. The PCM detects that the affected HO2S voltage parameter is between 410-490 mV for 150 seconds.
2. The TP Indicated Angle parameter changes more than 5 percent within 1 second, 6 times.

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 powertrain control module (PCM) controls the air/fuel metering system in order to provide the best possible combination of driveability, fuel economy, and emission control. Fuel delivery is controlled differently during Open and Closed Loop. During Open Loop, the PCM determines fuel delivery based on sensor signals without oxygen sensor input. During Closed Loop, the PCM adds oxygen sensor inputs and level of purge to calculate short and long term fuel trim adjustments. If the oxygen sensors indicate a lean condition, fuel trim values will be above 0 percent. If the oxygen sensors indicate a rich condition, fuel trim values will be below 0 percent. The values for the short term fuel trim change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. Long term fuel trim makes course adjustments in order to maintain an air/fuel ratio of 14.7:1. A block of cells contain information arranged in combinations of engine RPM and engine load for a full range of vehicle operating conditions. The long term fuel trim diagnostic is based on an average of cells currently being used. The PCM selects the cells based on the engine speed and engine load. If the PCM detects an excessively lean condition, DTC P0171 or P0174 sets.

This diagnostic procedure supports the following DTCs

1. DTC P0171 Fuel Trim System Lean Bank 1
2. DTC P0174 Fuel Trim System Lean Bank 2

1. DTCs P0030, P0036, P0050, P0053, P0054, P0056, P0059, P0060, P0101, P0102, P0103, P0106, P0107, P0108, P0131, P0132, P0133, P0134, P0135, P0137, P0138, P0140, P0141, P0151, P0152, P0153, P0154, P0155, P0157, P0158, P0160, P0161, P0200, P0300, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P0496, P0506, P0507, P1133, P1134, P1153, P1154, P2A01, P2A04 are not set.
2. The Fuel Trim Learn parameter is enabled.
3. The Loop Status parameter is closed.
4. The engine coolant temperature (ECT) is between -40 to +139°C (-40 to +282°F).
5. The intake air temperature (IAT) is between -20 to +152°C (-4 to +304°F).
6. The manifold absolute pressure (MAP) is between 15-105 kPa (2.2-15.2 psi).
7. The vehicle speed is less than 132 km/h (82 mph).
8. The engine speed is between 400-6,500 RPM.
9. The barometric pressure (BARO) is more than 70 kPa (10.2 psi).
10. The mass air flow (MAF) is between 1-250 g/s.
11. The fuel level is more than 15 percent.
12. This diagnostic runs continuously when the above conditions are met.

The long term fuel trim value is more than a calibrated value for approximately 3 minutes after the Conditions for Running the DTC have been met.

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 ignition cycle the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records. The control module illuminates the malfunction indicator lamp (MIL) when one of the following occur

1. The control module detects the same fuel trim failure during 2 consecutive trips.
2. The control module detects any fuel trim failure during any subsequent trip if the conditions at the time of failure meet the following criteria: The engine load is within 20 percent of the previous test that failed. The engine speed is within 375 RPM of the previous test that failed. The engine coolant temperature is in the same range of the previous test that failed.

1. The control module turns OFF the malfunction indicator lamp (MIL) at the beginning of the fourth ignition cycle, 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 and related Freeze Frame data clears after 80 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. Excessive resistance in the fuel injector control and/or the ignition 1 voltage circuits may cause the following symptoms: A lean condition Misfire Rough idle Refer to «DTC P0200»(ref-238271-S24330167442006072400000) .
2. The system may become lean if an injector is not suppling enough fuel.
3. A lean condition could be present during high fuel demand.
4. Review the Failure Records with a scan tool. If an intermittent condition is suspected, refer to «Testing for Intermittent Conditions and Poor Connections»(ref-238178-S33329058682006072400000) .

DTC P0171 or P0174