Engine Controls Diagnosis - 3.4l (DTC p0140-dtc p0496) Buick Rendezvous I

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 of the exhaust stream. When the vehicle is first started, the powertrain control module (PCM) operates in an Open Loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference, or bias, voltage of about 450 mV. The HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage once in Closed Loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and to provide an accurate voltage signal. The HO2S 2 is used for post catalyst monitoring. If the PCM detects that the HO2S 2 voltage remains at or near the bias voltage amount, DTC P0140 will set.

The HO2S 2 has the following circuits

1. A HO2S 2 high signal circuit
2. A HO2S 2 low signal circuit
3. A HO2S 2 heater ignition voltage circuit
4. A HO2S 2 heater ground circuit

Conditions for Running the DTC

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201-P0206, P0401, P0442, P0443, P0446, P0449, P0455, P0496 are not set.
2. The Engine Run Time parameter is longer than 2 minutes.
3. The system voltage is between 9-18 volts.
4. The diagnostic runs once per trip.
5. There is a throttle position (TP) sensor angle change of more than 8 percent at least 3 times during the test period.

Conditions for Setting the DTC

The PCM detects that the HO2S 2 signal voltage remains between 391-521 mV for more than 100 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.

DTC P0140

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 of the exhaust stream. When the vehicle is first started, the powertrain control module (PCM) operates in an Open Loop mode, ignoring the HO2S signal voltage when calculating the air-to-fuel ratio. The PCM supplies the HO2S with a reference, or bias, voltage of about 450 mV. The HO2S generates a voltage within a range of 0-1,000 mV that fluctuates above and below bias voltage once in Closed Loop. A high HO2S voltage output indicates a rich fuel mixture. A low HO2S voltage output indicates a lean mixture. Heating elements inside the HO2S minimize the time required for the sensors to reach operating temperature, and to provide an accurate voltage signal. The HO2S 2 heater performance diagnostic will only run from a cold start and only once per key cycle. The HO2S 2 heater circuit is energized anytime the ignition key is in the ON position. If the PCM detects that the HO2S 2 heater takes too long to heat, based on the HO2S 2 signal voltage, DTC P0141 will set. The HO2S 2 has the following circuits

1. A HO2S 2 high signal circuit
2. A HO2S 2 low signal circuit
3. A HO2S 2 heater ignition voltage circuit
4. A HO2S 2 heater ground circuit

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0201-P0206, P0401, P0442, P0443, P0446, P0449, P0455, P0496 are not set.
2. The Start-Up IAT parameter is less than 35°C (95°F).
3. The Start-Up ECT parameter is less than 35°C (95°F).
4. The intake air temperature (IAT) and engine coolant temperature (ECT) are within 6°C (11°F) of each other at start-up.
5. The system voltage is between 9-18 volts.
6. The MAF Sensor parameter is less than 20 g/s.

The PCM detects that the HO2S 2 voltage remains within 74 mV of the bias voltage, about 450 mV, for a longer amount of time than necessary. The amount of time ranges between 100-280 seconds depending on ECT at startup, and the average mass air flow (MAF) since startup.

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 P0141

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 Loop and Closed Loop. During Open Loop, the PCM determines fuel delivery based on sensor signals, without oxygen sensor (O2S) input. During Closed Loop, the PCM adds oxygen sensor inputs to calculate the short and long term fuel trim, fuel delivery adjustments. If the oxygen sensors indicate a lean condition, the fuel trim values will be above 0 percent. If the oxygen sensors indicate a rich condition, the fuel trim values will be below 0 percent. The short term fuel trim values change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. The long term fuel trim makes coarse adjustments in order to maintain an air/fuel ratio of 14.7:1. If the PCM detects an excessively lean condition, diagnostic trouble code (DTC) P0171 sets.

1. DTCs P0101-P0103, P0107, P0108, P0121- P0123, P0130-P0135, P0137, P0138, P0140, P0141, P0201-P0206, P0300, P0401, P0403-P0405, P0410, P0440, P0442, P0446, P0506, P0507, P1404, or P1441 are not set.
2. The engine coolant temperature (ECT) is between 20-110°C (68-230°F).
3. The intake air temperature (IAT) is between 18-70°C (64-158°F).
4. The manifold absolute pressure (MAP) is between 15-105 kPa (2.1-15.2 psi).
5. The vehicle speed is less than 132 km/h (82 mph).
6. The engine speed is between 550-4,000 RPM.
7. The barometric pressure (BARO) is more than 70 kPa (10.1 psi).
8. The mass airflow (MAF) is between 2.8-150 g/s.
9. The fuel level is more than 10 percent.

1. The average long term fuel trim value is above 20 percent.
2. All of the above conditions are present for 6 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.

Diagnostic Aids

1. The system will go lean if an injector is not supplying enough fuel.
2. A lean condition could be present during high fuel demand due to a fuel pump that does not pump enough fuel.
3. Fuel contamination, such as water and alcohol will effect the fuel trim.
4. Use a scan tool in order to review the Failure Records. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

Test Description

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

1. 5: If the conditions were not corrected, refer to Fuel System Diagnosis for a possible fuel condition.
2. 6: If the conditions were not corrected, a worn cam, worn intake or exhaust valves, or other engine mechanical failures may be at fault.

DTC P0171

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 Loop and Closed Loop. During Open Loop, the PCM determines fuel delivery based on sensor signals, without oxygen sensor input. During Closed Loop, the oxygen sensor inputs are added and used by the PCM to calculate the short and long term fuel trim (fuel delivery adjustments). If the oxygen sensors indicate a lean condition, the fuel trim values will be above 0 percent. If the oxygen sensors indicate a rich condition, the fuel trim values will be below 0 percent. The short term fuel trim values change rapidly in response to the heated oxygen sensor (HO2S) voltage signals. The long term fuel trim makes coarse adjustments in order to maintain Air/Fuel Ratio of 14.7:1. The fuel trim diagnostic will conduct a test to determine if a rich failure actually exists or if excessive vapor from the evaporative emission (EVAP) canister is causing a rich condition. If the PCM detects an excessively rich condition, diagnostic trouble code (DTC) P0172 sets.

1. DTCs P0101-P0103, P0107, P0108, P0121-P0123, P0130-P0135, P0137, P0138, P0140, P0141, P0201-P0206, P0300, P0401, P0403-P0405, P0410, P0412, P0418, P0440, P0442, P0446, P0506, P0507, P1404, or P1441 are not set.
2. The engine coolant temperature (ECT) is between 20-110°C (68-239°F).
3. The intake air temperature (IAT) is between 18-70°C (64-158°F).
4. The manifold absolute pressure (MAP) is between 15-105 kPa (2.1-15.2 psi).
5. The vehicle speed is less than 132 km/h (82 mph).
6. The engine speed is between 550-4,000 RPM.
7. The barometric pressure is more than 70 kPa (10.1 psi).
8. The mass air flow (MAF) is between 2.8-150 g/s.
9. The fuel level is more than 10 percent.

1. The average long term fuel trim value is below -13 percent.
2. All of the above conditions are present for 40 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. Fuel contamination, such as water and alcohol will effect the fuel trim.
2. A malfunctioning mass air flow (MAF) sensor can cause a rich condition and set this DTC. Refer to «DTC P0101»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-diagnosis-34l-dtc-p0030-dtc-p0138) .
3. Use a scan tool in order to review the Failure Records. If an intermittent condition is suspected, refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

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

1. 5: If the conditions were not corrected, refer to Fuel System Diagnosis for a possible fuel condition.
2. 6: An EVAP canister that is saturated will cause a rich condition. Fuel in the vacuum line to the fuel pressure regulator indicates a leaking regulator. If the conditions were not corrected, a worn cam, worn intake or exhaust valves, or other engine mechanical failure may be at fault.

DTC P0172

The powertrain control module (PCM) enables the appropriate fuel injector on the intake stroke for each cylinder. A voltage is supplied directly to the fuel injectors. The PCM controls each fuel injector by grounding the control circuit via a solid state device called a driver. The PCM monitors the status of each driver. If the PCM detects an incorrect voltage for the commanded state of the driver, a fuel injector control diagnostic trouble code (DTC) sets.

1. The engine is running.
2. The ignition voltage is between 9-18 volts.

1. The PCM detects an incorrect voltage on the fuel injector control circuit.
2. The condition exists for 30 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. Performing the Fuel Injector Coil Test may help isolate an intermittent condition. Refer to «Fuel Injector Coil Test»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting) .
2. If the condition is intermittent, refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

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

1. 2: The misfire current counters may not increment if certain DTCs are set. Use a scan tool to clear the DTCs. Monitoring the misfire current counters isolates which fuel injector is not operating. A cylinder that is misfiring can also cause the misfire current counters to increment for another cylinder. Diagnose the cylinder with the highest level of misfire first.
2. 4: This step isolates the condition. If the test lamp blinks, the PCM is providing ground to the fuel injector.
3. 5: This step tests if a ground is constantly being applied to the fuel injector.
4. 6: This step isolates the circuit between the multi-way connector and the PCM. An open or short to voltage on the fuel injector control circuit will not allow the test lamp to blink.
5. 8: This step inspects for fuel injector harness damage between the multi-way connector and the upper intake manifold. Careful inspection may isolate the condition before removal of the upper intake manifold.
6. 10: Perform the continuity test at the multi-way connector. If the DMM displays OL, test the circuits for an open or a poor connection.
7. 13: This step isolates the circuit between the multi-way connector and the fuel injector. A short to voltage on the fuel injector control circuit will set this DTC.

DTC P0201-P0206

The powertrain control module (PCM) provides ignition positive voltage to the coil side of the fuel pump relay. When the ignition switch is first turned ON, the PCM energizes the fuel pump relay, which applies power to the fuel pump. The PCM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the PCM de-energizes the fuel pump relay after 2 seconds. The PCM monitors the voltage on the fuel pump relay control circuit. If the PCM detects an incorrect voltage on the fuel pump relay control circuit, DTC P0230 sets.

1. The ignition is ON.
2. The system voltage is between 9-18 volts.

1. The PCM detects an incorrect voltage on the control circuit of the fuel pump relay.
2. The condition exists for less than 1 second.

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: Listen for a click when the fuel pump relay operates. Command both the ON and OFF states. Repeat the commands as necessary.
2. 4: This step verifies that the PCM is providing voltage to the fuel pump relay.
3. 5: This step tests for an open in the ground circuit to the fuel pump relay.
4. 6: This step tests if voltage is constantly being applied to the control circuit of the fuel pump relay.

DTC P0230

System Description

The powertrain control module (PCM) uses information from the ignition control (IC) module and the camshaft position (CMP) sensor in order to determine when an engine misfire is occurring. By monitoring variations in the crankshaft rotation speed for each cylinder, the PCM is able to detect individual misfire events. A misfire rate that is high enough can cause the 3-way catalytic converter (TWC) to overheat under certain driving conditions. The malfunction indicator lamp (MIL) will flash ON and OFF when the conditions for TWC overheating are present. If the PCM detects a misfire rate sufficient to cause emission levels to exceed mandated standards, DTC P0300 will set.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0315, P0336, P0341, P0502, P0503, P1106, P1107, P1114, P1115, P1121, P1122, P1351, P1352, P1361, P1362, P1374 are not set.
2. The engine speed is between 525-5,900 RPM.
3. The ignition voltage is between 9-18 volts.
4. The engine coolant temperature (ECT) is between -7 and +125°C (+21 and +255°F).
5. The fuel level is more than 10 percent.
6. The throttle position (TP) sensor angle is steady within 1 percent.
7. The antilock brake system (ABS) and the traction control system are not active.
8. The transmission is not changing gears.
9. The A/C clutch is not changing states.
10. The PCM is not in fuel shut-off or decel fuel cut-off mode.
11. The PCM is not receiving a rough road signal.

The PCM is detecting a crankshaft rotation speed variation indicating a misfire sufficient to cause emission levels to exceed mandated standards.

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. Excessive vibration from sources other than the engine could cause DTC P0300 to set. The following are possible sources of vibration: Variable thickness brake rotors-Refer to «Symptoms - Hydraulic Brakes»(/buick/rendezvous/i-2001-2007/remont/mechanical-hydraulic/#hydraulic-brake-system__symptoms-hydraulic-brakes) in Hydraulic Brakes. Worn or damaged accessory drive belt-Refer to «Symptoms - Engine Mechanical»(/buick/rendezvous/i-2001-2007/remont/mechanical/#engine-mechanical-34l-la1) in Engine Mechanical.
2. Spray water on the secondary ignition components using a spray bottle. Look and listen for arcing or misfiring.

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

1. 2: If the actual CKP variation values are not within the learned values, the misfire counters may increment.

DTC P0300

The crankshaft position (CKP) system variation learn feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, and the crankshaft position sensors. The calculated error allows the powertrain control module (PCM) to accurately compensate for reference period variations. This enhances the ability of the PCM to detect misfire events over a wider range of engine speed and load.

The CKP system variation compensating values are stored in PCM memory after a learn procedure has been performed. If the actual CKP variation is not within the CKP system variation compensating values stored in the PCM, DTC P0300 may set.

If the CKP system variation values are not stored in the PCM memory, DTC P0315 sets.

1. DTCs P0336, P0341, P1374 are not set.
2. The engine coolant temperature (ECT) is more than 70°C (158°F).

The CKP system variation values are not stored in the PCM memory.

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 P0315

The knock sensor (KS) produces an alternating current voltage at all engine speeds and loads. The powertrain control module (PCM) then adjusts the spark timing based on the amplitude and on the frequency of the KS signal. The PCM uses the KS signal in order to calculate the average voltage and assigns a voltage value. The PCM checks the KS and the related wiring by comparing the actual knock signal to the assigned voltage range. A normal KS signal should remain out of the assigned voltage range. This diagnostic trouble code (DTC) will set if the PCM malfunctions in a manner that will not allow proper diagnosis of the KS system.

1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0336, P0341, P0502, P0503, P1114, P1115, P1121, P1122 are not set.
2. The engine speed is between 1,000-5,000 RPM.
3. The throttle angle is more than 15 percent.
4. The engine load is more than 45 percent.
5. The engine coolant temperature (ECT) is more than 60°C (140°F).
6. The maximum spark retard is less than 15 degrees.
7. The system voltage is more than 9 volts.
8. The engine run time is more than 30 seconds.

1. The PCM detects a malfunction in the KS diagnostic circuitry which will not allow proper diagnosis of the KS circuit.
2. The above condition exists for at least 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.

DTC P0325

The knock sensor (KS) system enables the powertrain control module (PCM) to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The KS is located at the left side of the engine block. The KS produces an AC voltage that varies depending on the vibration level during engine operation. The PCM adjusts the spark timing based on the amplitude and the frequency of the KS signal. The PCM receives the KS signal through a signal circuit. The KS ground is supplied by the engine block through the sensor housing. The PCM uses the KS signal to calculate an average voltage range value. If the system is operating normally, the PCM should monitor the KS voltage varying above and below the voltage range. If the PCM detects the KS signal voltage within the voltage range, or the KS signal is not present, this DTC will set.

1. DTCs P0101, P0102, P0103, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0336, P0341, P0502, P0503, P1114, P1115, P1121, P1122 are not set.
2. The engine speed is between 1,000-5,000 RPM.
3. The engine has been running for a minimum of 30 seconds.
4. The throttle angle is more than 15 percent.
5. The engine load is more than 45 percent.
6. The engine coolant temperature (ECT) is more than 60°C (140°F).
7. The maximum spark retard is less than 15 degrees.
8. The system voltage is more than 9 volts.

1. The PCM detects a KS signal voltage within the average voltage range for at least 10 seconds.
2. The engine run time is more than 30 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 KS for physical damage. A KS that is dropped or damaged may cause a DTC to set.
2. Inspect the KS for proper installation. A KS that is loose or over torqued may cause a DTC to set. The KS should be free of thread sealant. The KS mounting surface should be free of burrs, casting flash, and foreign material.
3. For an intermittent condition, refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

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

1. 3: A fault in the 12-volt reference circuit of the 24X CKP sensor or the CMP sensor can cause this DTC to set.
2. 6: Tapping on the engine block will simulate an engine knock.

DTC P0327

The circuit uses 2 different types of crankshaft position (CKP) sensors. The CKP sensor B is connected directly to the ignition control (IC) module, and consists of the following circuits

1. The CKP sensor 1 signal circuit
2. The low reference circuit

The CKP sensor A connects directly to the powertrain control (PCM) module, and consists of the following circuits

1. The 12-volt reference circuit
2. The medium resolution engine speed signal circuit
3. The low reference circuit

If the PCM detects an incorrect number of CKP pulses, DTC P0336 sets.

The engine is running, and 3 X reference pulses are being received for a minimum of 3 seconds.

The ratio of 24 X reference pulses to 3 X reference pulses received by the PCM is incorrect.

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 P0336 can be caused by secondary components leaking high voltage into the ignition control (IC) module. Inspect for the following conditions

1. Incorrect harness routing near secondary ignition components.
2. Ignition coil arcing to wiring harness or IC module, inspect ignition coils for cracks, carbon tracking, or other signs of damage.
3. Secondary ignition wires arcing to wiring harness.
4. If the DTC is determined to be intermittent refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) in Wiring System.

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

1. 4: If sent here from DTC P0327 proceed with DTC P0336 Diagnostic even if P0336 has not failed this ignition.
2. 8: The 24X RPM on the scan tool should change each time the medium resolution engine speed signal circuit is touched.

DTC P0336

During cranking, the ignition control (IC) module monitors the 7X crankshaft position (CKP) sensor signal. Once the engine starts the IC module determines spark synchronization, by the camshaft position (CMP) sensor pulses. The powertrain control module (PCM) constantly monitors the number of pulses on the CMP signal circuit and compares the number of CMP pulses to the number of 24X reference pulses and the number of 3X reference pulses being received. If the PCM receives an incorrect number of pulses on the CMP signal circuit, DTC P0341 will set.

The engine is running.

The camshaft position (CMP) sensor reference pulse is not detected during every engine revolution.

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 following conditions may cause this DTC to set

1. Incorrect harness routing near secondary ignition components
2. Ignition coil arcing to wiring harness or IC module - Inspect the ignition coils for cracks, for carbon tracking, or for other signs of damage.
3. Camshaft reluctor wheel damage
4. The sensor coming in contact with the reluctor wheel
5. Foreign material passing between the sensor and the reluctor wheel
6. Excessive camshaft end-play

If the condition is intermittent, refer to Intermittent Conditions .

DTC P0341

The powertrain control module (PCM) tests the exhaust gas recirculation (EGR) system during deceleration. The PCM does this by momentarily commanding the EGR valve to open while monitoring the signal circuit of the manifold absolute pressure (MAP) sensor. When the EGR valve is opened, the PCM will expect to see a predetermined increase in MAP. If the expected increase in MAP is not detected, the PCM records the amount of MAP difference that was detected and adjusts a calibrated fail counter towards a calibrated fail threshold level. The number of EGR flow test counts required to exceed the fail threshold may vary according to the amount of detected EGR flow error.

Normally, the PCM will only allow one EGR flow test during an ignition cycle. To aid in verifying a repair, the PCM will allow up to twelve EGR flow test counts during the first ignition cycle following a code clear event. Between nine and twelve EGR flow test counts should be sufficient for the PCM to determine adequate EGR flow and pass the EGR flow test. If the PCM detects an EGR flow error, DTC P0401 sets.

1. DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0201, P0202, P0203, P0204, P0205, P0206, P0300, P0336, P0403, P0404, P0405, P0502, P0503, P0506, P0507, P1106, P1107, P1111, P1112, P1114, P1115, P1121, P1122, P1374, P1404 are not set.
2. The engine run time may need to be more than 3 minutes.
3. The Ignition 1 signal parameter is between 11-18 volts.
4. The gear selector is not in PARK or NEUTRAL.
5. The AC Relay Command parameter does not change.
6. The Current Gear parameter does not change.
7. The Intake Air Temperature (IAT) sensor parameter is between 0-100°C (32-212°F).
8. The Engine Coolant Temperature (ECT) sensor parameter is more than 75°C (167°F).
9. The Engine Speed parameter is between 1,050-1,300 RPM.
10. The Manifold Absolute Pressure (MAP) sensor parameter is between 15-70 kPa.
11. The Barometric Pressure (BARO) parameter is more than 74 kPa.
12. The Throttle Position (TP) sensor parameter is less than 1 percent.
13. The Vehicle Speed sensor parameter is more than 48 km/h (35 mph) during deceleration.
14. The power enrichment (PE) mode is not active.
15. The decel fuel cut off (DFCO) mode is not active.
16. The Idle Air Control (IAC) Position parameter does not change more than 5 counts while the above conditions are met.
17. The vehicle will need to be driven more than 80 km/h (50 mph), and then allowed to decelerate. When the vehicle is decelerating, while meeting all of the criteria listed above, the PCM will enable the EGR flow test to run. As the EGR flow test is running, you will see the desired EGR Position parameter and the EGR Position Sensor parameter on the scan tool momentarily change from 0 to a calibrated value above 0. Additionally, the EGR Flow Test Count parameter on the scan tool will increment when each EGR flow test is completed.

The MAP changes monitored by the PCM during the EGR flow tests indicate an insufficient amount of EGR flow.

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.

Inspect for the following conditions

1. A vacuum restriction to the MAP sensor-A skewed MAP sensor reading can cause the PCM to read incorrect MAP changes during the EGR flow test.
2. An engine that is running poorly due to a mechanical condition such as worn piston rings, worn camshaft, etc.-These types of conditions can cause low engine vacuum and thus can cause a less than expected MAP changes during the flow test.
3. Excessive back pressure in the exhaust system may cause this DTC to set. This condition can cause low engine vacuum and thus can cause a less than expected MAP changes during the EGR flow test. Possible causes of this could be a restriction in the exhaust system or non original equipment manufacture (OEM) exhaust parts.
4. Exhaust system leaks can cause an insufficient amount of EGR flow through the EGR valve. This condition can cause a less than expected MAP changes due to insufficient exhaust back pressure. possible causes of this could be a leaking exhaust system, a leaking EGR pipe or non original equipment manufacture (OEM) exhaust parts.
5. A restriction in the intake manifold such as carbon deposits and casting flash

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

1. 2: MAP sensor faults must be diagnosed first. A skewed MAP sensor reading could cause this DTC to set.

DTC P0401

The powertrain control module (PCM) controls the exhaust gas recirculation (EGR) valve with a solid state device called a driver. The driver supplies the EGR solenoid with 12 volts that is pulse width modulated (PWM) through the EGR solenoid high control circuit. A ground path is provided by the PCM through the EGR solenoid low control circuit. The driver has the ability to detect an electrical malfunction on the EGR solenoid control circuits. If the PCM determines that the driver has detected an electrical malfunction on one of these circuits, DTC P0403 sets.

1. The engine is cranking or running.
2. The Ignition 1 Signal parameter is between 9-18 volts.

1. The PCM detects an electrical malfunction in the EGR solenoid high control circuit or the EGR solenoid low control circuit.
2. The above condition is met for more than 20 seconds.

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

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

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

1. 6: This step tests for voltage that is constantly being applied to the EGR valve.

DTC P0403

The exhaust gas recirculation (EGR) valve position sensor is monitored by the powertrain control module (PCM). The 5-volt reference circuit, low reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. The PCM compares the EGR Position Sensor parameter with the desired EGR Position parameter when the valve is commanded open or closed. If the PCM detects a calibrated difference between the EGR Position Sensor parameter and desired EGR Position parameter for a calibrated amount of time, when the EGR valve is commanded open, DTC P0404 sets.

1. The Ignition 1 Signal parameter is more than 11 volts.
2. The EGR command will be disabled if the startup engine coolant temperature (ECT) is less than 5°C (41°F) and will not enable until the ECT is more than 75°C (167°F).
3. The EGR valve is commanded to open.
4. The EGR flow test is not active.

1. The difference between the EGR Position Sensor parameter and the desired EGR Position parameter is more than 15 percent.
2. The above condition is met for more than 20 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 for excessive deposits on the EGR pintle or seat. Inspect for deposits that may interfere with the EGR valve pintle extending completely or cause the pintle to stick.
2. If the condition is intermittent, refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

DTC P0404

The exhaust gas recirculation (EGR) valve position sensor is monitored by the powertrain control module (PCM). The 5-volt reference circuit, low reference circuit and the EGR valve position signal circuit are used by the PCM to determine the EGR valve position. If the EGR valve position sensor signal voltage is pulled below a calibrated value, DTC P0405 sets.

1. The Ignition 1 Signal parameter is more than 11 volts.
2. The EGR command will be disabled if the startup engine coolant temperature (ECT) is less than 5°C (41°F) and will not enable until the ECT is more than 75°C (167°F).

1. The EGR Position Sensor parameter is less than 0.35 volts.
2. The above condition is met for more than 20 seconds.

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

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

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

1. 9: By disconnecting each component one at a time, the component that is pulling the 5-volt reference circuit low will be revealed.

DTC P0405

A three-way catalytic (TWC) converter controls emissions of hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx). The catalyst within the converter promotes a chemical reaction which oxidizes the HC and the CO that are present in the exhaust gas. This process converts the HC and the CO into water vapor and carbon dioxide (CO2), and reduces the NOx, converting the NOx into nitrogen. The catalytic converter also stores oxygen. The powertrain control module (PCM) monitors this process by using a heated oxygen sensor (HO2S) that is in the exhaust stream after the TWC. This HO2S 2, also referred to as the catalyst monitor sensor, produces an output signal that the PCM uses to calculate the oxygen storage capacity of the catalyst. This indicates the ability of the catalyst to convert the exhaust emissions efficiently. The PCM monitors the efficiency of the catalyst by allowing the catalyst to heat, then wait for a stabilization period while the engine is idling. The PCM then adds and removes fuel while monitoring the HO2S 2. When the catalyst is functioning properly, the HO2S 2 response to the extra fuel is slow compared to the response of the HO2S 1, which is located before the TWC. When the HO2S 2 response is near that of the HO2S 1, the oxygen storage capability and efficiency of the catalyst is considered to be degraded below an acceptable threshold. If the PCM detects the degraded condition, DTC P0420 sets.

1. DTCs P0030, P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0135, P0136, P0137, P0138, P0140, P0141, P0171, P0172, P0201-P0206, P0300, P0336, P0341, P0404, P0405, P0442, P0443, P0455, P0496, P0502, P0503, P0506, P0507, P1133, P1134, P1351, P1352, P1361, P1362 are not set.
2. The engine has been running longer than 10 minutes.
3. The engine coolant temperature (ECT) is between 75-167°C (169-255°F).
4. The barometric pressure (BARO) is above 74 kPa.
5. The vehicle is in Closed Loop.
6. The intake air temperature (IAT) is between -20 to +100°C (-4 to +212°F).
7. The engine load must be stable.
8. The engine speed is within 150 RPM above or 127 RPM below the desired idle.
9. The throttle position (TP) is below 1.5 percent.
10. The short term fuel trim (FT) is between -1.5 and +1.5 percent.
11. The battery voltage above 10.7 volts.
12. The catalyst test will abort if the vehicle falls outside the conditions listed above while the test is running.

1. Warm up the catalyst. Fully open the hood. The transmission is in Park, automatic, or Neutral, manual. Set the parking brake. Press and hold the service brake. Each time the engine is started, the diagnostic can run up to 18 times if the tests are a combination of passes and failures. If each subsequent test is a pass the diagnostic will run a maximum of 6 times. After the 10 minute run time, and before the diagnostic runs the first time, the engine must run an additional 3 minutes between 1,500-2,500 RPM. For any additional tests on the same key cycle, the engine must be between 1,500-2,500 RPM for 1 minute. In order to activate the diagnostic, return the engine to idle and place the vehicle in drive.
2. Test the catalyst. The transaxle is in drive. Within 60 seconds the air/fuel ratio will transition rich, below 13.7, for up to 7 seconds. The air/fuel ratio may then transition lean, above 16, for up to 7 seconds. Using the scan tool, check and see if DTC P0420 has passed or failed this key cycle.

The PCM determines that the catalyst's oxygen storage capacity is below a threshold considered acceptable.

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

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

1. These conditions may cause a catalytic converter to degrade. Inspect for the following conditions: An engine misfire High engine oil or high coolant consumption Retarded spark timing A weak or poor spark A lean fuel mixture A rich fuel mixture A damaged oxygen sensor or wiring harness
2. If an intermittent condition cannot be duplicated, the information included in the Freeze Frame Records can be useful in determining the vehicle operating conditions when the DTC was set.
3. The catalyst may have been temporarily contaminated with a chemical from a fuel additive or fuel contamination.
4. More than 6 tests may have to be attempted in order to get 6 completed tests. An aborted test counts as an attempted test.
5. If 18 tests have been attempted, and a decision has not been made this key cycle, turn the key OFF for 30 seconds, start the vehicle, and perform the Conditions for Running the DTC, including the 10 minute run time.
6. After returning to an idle, the HO2S 1 signal may stay rich or lean for several seconds, causing the test to be delayed.
7. DO NOT touch the accelerator pedal, steering wheel, or HVAC controls while a catalyst test is in progress.

If the condition is determined to be intermittent, refer to Intermittent Conditions .

DTC P0420

This DTC tests the evaporative emission (EVAP) system for a small leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the vacuum decay rate. At an appropriate time, the control module turns the EVAP canister purge solenoid valve ON and the EVAP canister vent solenoid valve ON. This allows the engine to draw a vacuum on the EVAP system. At a calibrated time, or vacuum level, the control module turns the EVAP canister purge solenoid valve OFF, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum decay. If the control module detects a leak larger than a calibrated amount, 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 P0442

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0455, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, P1122 are not set.
2. The ignition voltage is between 10-18 volts.
3. The barometric pressure (BARO) is more than 75 kPa.
4. The fuel level is between 15-80 percent.
5. The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
6. The intake air temperature (IAT) is between 4-30°C (39-86°F).
7. The start up ECT and IAT are within 9°C (16°F) of each other.
8. The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

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

1. The control module illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.
2. The control module records the operating conditions at the time the diagnostic fails. The control module stores this information in the Freeze Frame/Failure Records.

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

1. To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
2. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
3. For intermittent conditions refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .
4. A condition may exist where a leak in the EVAP system only exists under a vacuum condition. By using the scan tool PURGE/SEAL function to create a vacuum, seal the system and observe the FTP parameter for vacuum decay, this type of leak may be detected.

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

1. 2: This step verifies that a failure condition is present.
2. 4: Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
3. 6: This step verifies that repairs are complete and that no other condition is present.

DTC P0442

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. The control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.

1. The engine speed is more than 400 RPM.
2. The system voltage is between 6-18 volts.

1. The control module detects that the commanded state of the driver and the actual state of the control circuit do NOT match.
2. The above conditions are present for a minimum of 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 numbers below refer to the step numbers on the diagnostic table.

1. 2: This step tests if the concern is active. The EVAP canister purge solenoid valve is PWM. Clicking should be heard or felt when the valve is commanded to 50 percent and should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase as the commanded state is increased and decreased as the commanded state is decreased.
2. 5: This step tests if a ground is constantly being applied to the EVAP canister purge solenoid valve.
3. 6: This step verifies that the control module is providing ground to the EVAP purge solenoid valve.

DTC P0443

This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve OPEN and the EVAP canister vent solenoid valve CLOSED. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve CLOSED and the EVAP canister vent solenoid valve OPEN. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated 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 P0446

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0455, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, P1122 are not set.
2. The ignition voltage is between 10-18 volts.
3. The barometric pressure (BARO) is more than 75 kPa.
4. The fuel level is between 15-80 percent.
5. The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
6. The intake air temperature (IAT) is between 4-30°C (39-86°F).
7. The start up ECT and IAT are within 9°C (16°F) of each other.
8. The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

1. The FTP sensor is less than -10 inches H2O.
2. The condition is present for as long as 30 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 could be caused by a damaged EVAP vent housing, a temporary blockage at the EVAP canister vent solenoid valve inlet, or a pinched vent hose. A blockage in the vent system will also cause a poor fuel fill problem.
2. An EVAP canister valve, a vent hose valve, or a vent solenoid valve that has restricted flow may cause this DTC to set. Using the purge solenoid valve command with a scan tool will allow vacuum to be applied to the system instead of pressure. With the EVAP canister vent solenoid valve open and the EVAP canister purge solenoid valve commanded to 100 percent, vacuum should not increase to more then 9 in H2O.
3. For intermittent conditions refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

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

1. 4: This test determines if the failure is present or intermittent.

DTC P0446

An ignition voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent solenoid valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, 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 vent solenoid valve.

DTC P0449

1. The engine speed is more than 400 RPM.
2. The system voltage is between 6-18 volts.

1. The control module detects that the commanded state of the driver and the actual state of the control circuit do NOT match.
2. The above conditions are present for a minimum of 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 numbers below refer to the step numbers on the diagnostic table.

1. 2: Listen or feel for a click when the EVAP canister vent solenoid valve operates. Ensure that both the ON and the OFF states are commanded.
2. 5: This step verifies that the control module is providing ground to the EVAP canister vent solenoid valve.
3. 6: This step tests if the EVAP canister vent solenoid valve control circuit is grounded.

DTC P0449

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage goes below a calibrated value, this DTC sets.

The following table illustrates the relationship between the FTP sensor signal voltage and the EVAP system pressure/vacuum.

DTC P0452

The key is ON.

1. The FTP sensor voltage is less than 0.1 volt.
2. All conditions are present for more than 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 number below refers to the step number on the diagnostic table.

1. 5: This step tests for the proper operation of the circuit in the high voltage range.

DTC P0452

The fuel tank pressure (FTP) sensor measures the difference between the air pressure or vacuum in the evaporative emission (EVAP) system, and the outside air pressure. The control module supplies a 5-volt reference and a low reference circuit to the FTP sensor. The FTP sensor signal circuit voltage varies depending on EVAP system pressure or vacuum. If the FTP sensor signal voltage increases above a calibrated value, this DTC sets.

The following table illustrates the relationship between FTP sensor signal voltage and the EVAP system pressure/vacuum.

DTC P0453

The key is ON.

1. The FTP sensor voltage is more than 4.9 volts.
2. All conditions are present for more than 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 number below refers to the step number on the diagnostic table.

1. 2: If DTC P1639 set, the 5-volt reference circuit may be shorted to a voltage.

DTC P0453

The control module tests the evaporative emission (EVAP) system for a large leak. The control module monitors the fuel tank pressure (FTP) sensor signal to determine the EVAP system vacuum level. When the conditions for running are met, the control module commands the EVAP canister purge solenoid valve OPEN and the EVAP canister vent solenoid valve CLOSED. This allows engine vacuum to enter the EVAP system. At a calibrated time, or vacuum level, the control module commands the EVAP canister purge solenoid valve CLOSED, sealing the system, and monitors the FTP sensor input in order to determine the EVAP system vacuum level. If the system is unable to achieve the calibrated vacuum level, or the vacuum level decreases too rapidly, 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 P0455

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0443, P0449, P0452, P0453, P1106, P1107, P1112, P1114, P1115, P1121, P1122 are not set.
2. The engine is running.
3. The ignition voltage is between 10-18 volts.
4. The barometric pressure (BARO) is more than 75 kPa.
5. The fuel level is between 15-85 percent.
6. The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
7. The intake air temperature (IAT) is between 4-30°C (39-86°F).
8. The start up ECT and IAT are within 9°C (16°F) of each other.
9. The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

The EVAP system is not able to achieve or maintain vacuum during the diagnostic test.

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

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

1. To help locate intermittent leaks, use the J 41413-200 Evaporative Emissions System Tester (EEST) to introduce smoke into the EVAP system. Move all EVAP components while observing smoke with the J 41413-SPT High Intensity White Light.
2. A temporary blockage in the EVAP canister purge solenoid valve, purge pipe or EVAP canister could cause an intermittent condition. Inspect and repair any restriction in the EVAP system.
3. To improve the visibility of the smoke exiting the EVAP system, observe the suspected leak area from different angles with the J 41413-SPT .
4. 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.
5. For intermittent conditions, refer to «Intermittent Conditions»(/buick/rendezvous/i-2001-2007/remont/testing-diagnostics/#engine-controls-34l-troubleshooting__intermittent-conditions) .

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

1. 2: This step verifies that a failure condition is active.
2. 4: Introducing smoke in 15 second intervals may allow smaller leak areas to be more noticeable. When the system is less pressurized, the smoke will sometimes escape in a more condensed manner.
3. 6: This step verifies proper operation of the FTP sensor.
4. 7: A normal operating FTP sensor should increase above 5 inches of H20 and stop between 6 inches of H20 and 7 inches of H20.
5. 9: This step tests the EVAP canister purge solenoid valve vacuum source between the EVAP canister purge solenoid valve and the intake manifold for restrictions or blockages.

DTC P0455

This DTC tests for undesired 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 solenoid and vent solenoid valves.

DTC P0496

1. DTCs P0107, P0108, P0112, P0113, P0116, P0117, P0118, P0121, P0122, P0123, P0125, P0442, P0443, P0446, P0449, P0452, P0453, P0455, P1106, P1107, P1112, P1114, P1115, P1121, P1122 are not set.
2. The ignition voltage is between 10-18 volts.
3. The barometric pressure (BARO) is more than 75 kPa.
4. The fuel level is between 15-85 percent.
5. The engine coolant temperature (ECT) is between 4-30°C (39-86°F).
6. The intake air temperature (IAT) is between 4-30°C (39-86°F).
7. The start up ECT and IAT are within 9°C (16°F) of each other.
8. The vehicle speed sensor (VSS) is less than 121 km/h (75 mph).

The control module detects 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 the 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 in the EVAP canister purge solenoid valve.

For intermittent conditions refer to Intermittent Conditions .

DTC P0496

See also:
• Engine Controls Schematics
• Engine Controls Connector End Views
• Powertrain Control Module (PCM) Connector End Views
• Diagnostic System Check - Engine Controls
• Scan Tool Data List
• Intermittent Conditions
• Circuit Testing
• Silicon Contamination of Heated Oxygen Sensors Notice
• Heated Oxygen and Oxygen Sensor Notice
• Inspection/Maintenance (I/M) Evaporative Emission (EVAP) System Set Procedure
• Testing for Intermittent Conditions and Poor Connections
• Connector Repairs
• Heated Oxygen Sensor (HO2S) Wiring Repairs
• Wiring Repairs
• Powertrain Control Module (PCM) Replacement
• Diagnostic Trouble Code (DTC) List
• Alcohol/Contaminants-in-Fuel Diagnosis (Without Special Tool)
• Symptoms - Engine Mechanical
• DTC P0101
• Testing for Continuity
• Symptoms - Hydraulic Brakes
• CKP System Variation Learn Procedure
• Exhaust Gas Recirculation (EGR) System Cleaning
• Restricted Exhaust
• Spark Plug Wire Inspection
• Spark Plug Inspection
• Crankshaft and Bearings Cleaning and Inspection
• Testing for Short to Ground
• Testing for a Short to Voltage
• Power Steering Pump Replacement (LA1 )
• Probing Electrical Connectors
• Using Connector Test Adapters
• DTC P0641
• Exhaust Leakage
• Lifting and Jacking the Vehicle
• DTC P0420