Engine Control System Sfi System (Diagnostic Codes (P0136 - P0441)): Overview Toyota Avalon XX30 рестайлинг 2

DESCRIPTION

A three-way catalytic converter (TWC) is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the TWC to function effectively, it is necessary to keep the air-fuel ratio of the engine near the stoichiometric air-fuel ratio. For the purpose of helping the ECM to deliver accurate air-fuel ratio control, the Heated Oxygen (HO2) sensor is used.

The HO2 sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).

When the air-fuel ratio becomes lean, the oxygen concentration in the exhaust gas becomes rich. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. less than 0.45 V).

Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel level, the oxygen concentration in the exhaust gas becomes lean. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is rich (high voltage, i.e. more than 0.45 V). The HO2 sensor has the property of changing its output voltage drastically when the air-fuel ratio is close to the stoichiometric level.

The ECM uses the supplementary information from the HO2 sensor to determine whether the air-fuel ratio after the TWC is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the HO2 sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air-fuel ratio control.

Scheme 124

Scheme 125

Scheme 126

Scheme 127

1. Active Air-Fuel Ratio Control The ECM usually performs air-fuel ratio feedback control so that the Air-Fuel Ratio (A/F) sensor output indicates a near stoichiometric air-fuel level. This vehicle includes active air-fuel ratio control in addition to regular air-fuel ratio control. The ECM performs active air-fuel ratio control to detect any deterioration in the Three-Way Catalytic Converter (TWC) and Heated Oxygen (HO2) sensor malfunctions (refer to the diagram below). Active air-fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine. During active air-fuel ratio control, the air-fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, one of the following DTCs is set: DTC P0136 or P0156 (abnormal voltage output), P0137 or P0157 (open circuit) or P0138 or P0158 (short circuit).
2. Abnormal Voltage Output of HO2 Sensor (DTCs P0136 and P0156) While the ECM is performing active air-fuel ratio control, the air-fuel ratio is forcibly regulated to become rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when the HO2 sensor voltage does not decrease to less than 0.21 V and does not increase to more than 0.59 V during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets DTCs P0136 and P0156.
3. Open or Short in Heated Oxygen (HO2) Sensor Circuit (DTCs P0137 and P0157 or P0138 and P0158) During active air-fuel ratio control, the ECM calculates the Oxygen Storage Capacity (OSC) * of the Three-Way Catalytic Converter (TWC) by forcibly regulating the air-fuel ratio to become rich or lean. If the HO2 sensor has an open or short circuit, or the voltage output of the sensor noticeably decreases, the OSC indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air-fuel ratio to become rich or lean, the HO2 sensor output does not change. While performing active air-fuel ratio control, when the target air-fuel ratio is rich and the HO2 sensor voltage output is 0.21 V or less (lean), the ECM interprets this as an abnormally low sensor output voltage and sets DTC P0137 or P0157. When the target air-fuel ratio is lean and the voltage output is 0.59 V or more (rich) during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormally high, and sets DTC P0138 or P0158. HINT: DTC P0138 or P0158 is also set if the HO2 sensor voltage output is 1.2 V or more for 10 seconds or more. *: The TWC has the capability to store oxygen. The OSC and the emission purification capacity of the TWC are mutually related. The ECM determines whether the catalyst has deteriorated, based on the calculated OSC value. Refer to «DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2)»(ref-428884-S16117257652011101200000).
4. High or Low Impedance of Heated Oxygen (HO2) Sensor (DTCs P0136 and P0156 or P0137 and P0157) During normal air-fuel ratio feedback control, there are small variations in the exhaust gas oxygen concentration. In order to continuously monitor the slight variation of the HO2 sensor signal while the engine is running, the impedance * of the sensor is measured by the ECM. The ECM determines that there is a malfunction in the sensor when the measured impedance deviates from the standard range. * : The effective resistance in an alternating current electrical circuit. HINT: The impedance cannot be measured using an ohmmeter. DTCs P0136 and P0156 indicate the deterioration of the HO2 sensor. The ECM sets the DTCs by calculating the impedance of the sensor when the typical enabling conditions are satisfied (2 driving cycle). DTCs P0137 and P0157 indicate an open or short circuit in the HO2 sensor (2 driving cycle). The ECM sets the DTCs when the impedance of the sensor exceeds the threshold of 15 kohms.
5. Abnormal Voltage Output of Heated Oxygen Sensor During Fuel-cut (DTC P0139 and P0159) The sensor output voltage drops to below 0.2 V (extremely lean status) immediately when the vehicle decelerates and fuel cut is operating. If the voltage does not drop to below 0.2 V for 7 seconds or more, or voltage does not drop from 0.35 V to 0.2 V for 1 second the ECM determines that the sensor's response has deteriorated, illuminates the MIL and sets a DTC.

A three-way catalytic converter (TWC) is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the TWC to function effectively, it is necessary to keep the air-fuel ratio of the engine near the stoichiometric air-fuel ratio. For the purpose of helping the ECM to deliver accurate air-fuel ratio control, the Heated Oxygen (HO2) sensor is used.

The HO2 sensor is located behind the TWC, and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with the heater that heats the sensing portion, it is possible to detect the oxygen concentration even when the intake air volume is low (the exhaust gas temperature is low).

When the air-fuel ratio becomes lean, the oxygen concentration in the exhaust gas becomes rich. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is lean (low voltage, i.e. less than 0.45 V).

Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel level, the oxygen concentration in the exhaust gas becomes lean. The HO2 sensor informs the ECM that the post-TWC air-fuel ratio is rich (high voltage, i.e. more than 0.45 V). The HO2 sensor has the property of changing its output voltage drastically when the air-fuel ratio is close to the stoichiometric level.

The ECM uses the supplementary information from the HO2 sensor to determine whether the air-fuel ratio after the TWC is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the HO2 sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in the primary air-fuel ratio control.

MONITOR DESCRIPTION

1. Active Air-Fuel Ratio Control The ECM usually performs air-fuel ratio feedback control so that the Air-Fuel Ratio (A/F) sensor output indicates a near stoichiometric air-fuel level. This vehicle includes active air-fuel ratio control in addition to regular air-fuel ratio control. The ECM performs active air-fuel ratio control to detect any deterioration in the Three-Way Catalytic Converter (TWC) and Heated Oxygen (HO2) sensor malfunctions (refer to the diagram below). Active air-fuel ratio control is performed for approximately 15 to 20 seconds while driving with a warm engine. During active air-fuel ratio control, the air-fuel ratio is forcibly regulated to become lean or rich by the ECM. If the ECM detects a malfunction, one of the following DTCs is set: DTC P0136 or P0156 (abnormal voltage output), P0137 or P0157 (open circuit) or P0138 or P0158 (short circuit).
2. Abnormal Voltage Output of HO2 Sensor (DTCs P0136 and P0156) While the ECM is performing active air-fuel ratio control, the air-fuel ratio is forcibly regulated to become rich or lean. If the sensor is not functioning properly, the voltage output variation is small. For example, when the HO2 sensor voltage does not decrease to less than 0.21 V and does not increase to more than 0.59 V during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormal and sets DTCs P0136 and P0156.
3. Open or Short in Heated Oxygen (HO2) Sensor Circuit (DTCs P0137 and P0157 or P0138 and P0158) During active air-fuel ratio control, the ECM calculates the Oxygen Storage Capacity (OSC) * of the Three-Way Catalytic Converter (TWC) by forcibly regulating the air-fuel ratio to become rich or lean. If the HO2 sensor has an open or short circuit, or the voltage output of the sensor noticeably decreases, the OSC indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air-fuel ratio to become rich or lean, the HO2 sensor output does not change. While performing active air-fuel ratio control, when the target air-fuel ratio is rich and the HO2 sensor voltage output is 0.21 V or less (lean), the ECM interprets this as an abnormally low sensor output voltage and sets DTC P0137 or P0157. When the target air-fuel ratio is lean and the voltage output is 0.59 V or more (rich) during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormally high, and sets DTC P0138 or P0158. HINT: DTC P0138 or P0158 is also set if the HO2 sensor voltage output is 1.2 V or more for 10 seconds or more. *: The TWC has the capability to store oxygen. The OSC and the emission purification capacity of the TWC are mutually related. The ECM determines whether the catalyst has deteriorated, based on the calculated OSC value. Refer to «DTC P0420: Catalyst System Efficiency Below Threshold (Bank 1); DTC P0430: Catalyst System Efficiency Below Threshold (Bank 2)»(ref-428884-S36116724762011101200000).
4. High or Low Impedance of Heated Oxygen (HO2) Sensor (DTCs P0136 and P0156 or P0137 and P0157) During normal air-fuel ratio feedback control, there are small variations in the exhaust gas oxygen concentration. In order to continuously monitor the slight variation of the HO2 sensor signal while the engine is running, the impedance * of the sensor is measured by the ECM. The ECM determines that there is a malfunction in the sensor when the measured impedance deviates from the standard range. * : The effective resistance in an alternating current electrical circuit. HINT: The impedance cannot be measured using an ohmmeter. DTCs P0136 and P0156 indicate the deterioration of the HO2 sensor. The ECM sets the DTCs by calculating the impedance of the sensor when the typical enabling conditions are satisfied (2 driving cycle). DTCs P0137 and P0157 indicate an open or short circuit in the HO2 sensor (2 driving cycle). The ECM sets the DTCs when the impedance of the sensor exceeds the threshold of 15 kohms.
5. Abnormal Voltage Output of Heated Oxygen Sensor During Fuel-cut (DTC P0139 and P0159) The sensor output voltage drops to below 0.2 V (extremely lean status) immediately when the vehicle decelerates and fuel cut is operating. If the voltage does not drop to below 0.2 V for 7 seconds or more, or voltage does not drop from 0.35 V to 0.2 V for 1 second the ECM determines that the sensor's response has deteriorated, illuminates the MIL and sets a DTC.

HINT

1. Refer to DTC P2195. Refer to «DESCRIPTION»(ref-428883-S12025430352011101200000).
2. Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.

* Calculated by ECM based on the A/F sensor output

After the engine is warm, the ECM carries out air-fuel ratio feedback control, and maintains the air-fuel ratio at the theoretical level. In addition, after all the preconditions have been met, active air-fuel ratio control is carried out for approx. 10 seconds, and during active air-fuel ratio control, the ECM measures the response of the A/F sensor by increasing or decreasing a specific injection quantity based on the theoretical air-fuel ratio learned during normal air-fuel control. The ECM determines whether there is an A/F sensor malfunction at the mid-point of active air-fuel ratio control.

If the A/F sensor's response ability is reduced, DTC P014C, P014D, P014E and P014F are output.

If the time it takes the A/F sensor output to change is delayed, DTC P015A, P015B, P015C and P015D are output.

Scheme 128

HINT

1. Refer to DTC P2195. Refer to «DESCRIPTION»(ref-428883-S33108738322011101200000).
2. Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.

* Calculated by ECM based on the A/F sensor output

After the engine is warm, the ECM carries out air-fuel ratio feedback control, and maintains the air-fuel ratio at the theoretical level. In addition, after all the preconditions have been met, active air-fuel ratio control is carried out for approx. 10 seconds, and during active air-fuel ratio control, the ECM measures the response of the A/F sensor by increasing or decreasing a specific injection quantity based on the theoretical air-fuel ratio learned during normal air-fuel control. The ECM determines whether there is an A/F sensor malfunction at the mid-point of active air-fuel ratio control.

If the A/F sensor's response ability is reduced, DTC P014C, P014D, P014E and P014F are output.

If the time it takes the A/F sensor output to change is delayed, DTC P015A, P015B, P015C and P015D are output.

The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both short-term and long-term fuel trims.

The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. The signal from the Air-Fuel Ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air-fuel ratio is rich or an increase in the fuel injection volume if it is lean.

Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to deviate from the central value. The long-term fuel trim, which controls overall fuel compensation, compensates for long-term deviations in the fuel trim from the central value caused by the short-term fuel trim compensation.

If both the short-term and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.

HINT

1. When DTC P0171 or P0174 is set, the actual air-fuel ratio is on the lean side. When DTC P0172 or P0175 is set, the actual air-fuel ratio is on the rich side.
2. If the vehicle runs out of fuel, the air-fuel ratio is lean and DTC P0171 or P0174 may be set. The MIL is then illuminated.
3. When the total of the short-term and long-term fuel trim values is within the malfunction threshold (and the engine coolant temperature is more than 75°C [167°F]), the system is functioning normally.

Under closed-loop fuel control, fuel injection volumes that deviate from those estimated by the ECM cause changes in the long-term fuel trim compensation value. The long-term fuel trim is adjusted when there are persistent deviations in the short-term fuel trim values. Deviations from the ECM's estimated fuel injection volumes also affect the average fuel trim learning value, which is a combination of the average short-term fuel trim (fuel feedback compensation value) and the average long-term fuel trim (learning value of the air-fuel ratio). If the average fuel trim learning value exceeds the malfunction thresholds, the ECM interprets this as a fault in the fuel system and sets a DTC.

Example

Scheme 129

1. The average fuel trim learning value is +35% or more, or -35% or less, the ECM interprets this as a fuel system malfunction.

The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both short-term and long-term fuel trims.

The short-term fuel trim is fuel compensation that is used to constantly maintain the air-fuel ratio at stoichiometric levels. The signal from the Air-Fuel Ratio (A/F) sensor indicates whether the air-fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air-fuel ratio is rich or an increase in the fuel injection volume if it is lean.

Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to deviate from the central value. The long-term fuel trim, which controls overall fuel compensation, compensates for long-term deviations in the fuel trim from the central value caused by the short-term fuel trim compensation.

If both the short-term and long-term fuel trims are lean or rich beyond predetermined values, it is interpreted as a malfunction, and the ECM illuminates the MIL and sets a DTC.

HINT

1. When DTC P0171 or P0174 is set, the actual air-fuel ratio is on the lean side. When DTC P0172 or P0175 is set, the actual air-fuel ratio is on the rich side.
2. If the vehicle runs out of fuel, the air-fuel ratio is lean and DTC P0171 or P0174 may be set. The MIL is then illuminated.
3. When the total of the short-term and long-term fuel trim values is within the malfunction threshold (and the engine coolant temperature is more than 75°C [167°F]), the system is functioning normally.

Under closed-loop fuel control, fuel injection volumes that deviate from those estimated by the ECM cause changes in the long-term fuel trim compensation value. The long-term fuel trim is adjusted when there are persistent deviations in the short-term fuel trim values. Deviations from the ECM's estimated fuel injection volumes also affect the average fuel trim learning value, which is a combination of the average short-term fuel trim (fuel feedback compensation value) and the average long-term fuel trim (learning value of the air-fuel ratio). If the average fuel trim learning value exceeds the malfunction thresholds, the ECM interprets this as a fault in the fuel system and sets a DTC.

Example

1. The average fuel trim learning value is +35% or more, or -35% or less, the ECM interprets this as a fuel system malfunction.

When the engine misfires, high concentrations of hydrocarbons enter the exhaust gas. High hydrocarbons concentration levels can cause increase in exhaust emission levels. Extremely high concentrations of hydrocarbons can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the three-way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the VVT sensor and the crankshaft position sensor. The VVT sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels, the ECM illuminates the MIL and sets a DTC.

When multiple DTCs for misfiring cylinders are set, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set when several misfiring cylinders are detected at the same time.

Scheme 130

The ECM illuminates the MIL and sets a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

1. Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.
2. An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).

1. At a high engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs once.
2. At a normal engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs 3 times.

HINT

If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.

When the engine misfires, high concentrations of hydrocarbons enter the exhaust gas. High hydrocarbons concentration levels can cause increase in exhaust emission levels. Extremely high concentrations of hydrocarbons can also cause increases in the three-way catalytic converter temperature, which may cause damage to the three-way catalytic converter. To prevent this increase in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire rate. When the temperature of the three-way catalytic converter reaches the point of thermal degradation, the ECM blinks the MIL. To monitor misfires, the ECM uses both the VVT sensor and the crankshaft position sensor. The VVT sensor is used to identify any misfiring cylinders and the crankshaft position sensor is used to measure variations in the crankshaft rotation speed. Misfires are counted when the crankshaft rotation speed variations exceed predetermined thresholds. If the misfire count exceeds the threshold levels, the ECM illuminates the MIL and sets a DTC.

When multiple DTCs for misfiring cylinders are set, but DTC P0300 is not set, it indicates that misfires have been detected in different cylinders at different times. DTC P0300 is only set when several misfiring cylinders are detected at the same time.

The ECM illuminates the MIL and sets a DTC when either one of the following conditions, which could cause emission deterioration, is detected (2 trip detection logic).

1. Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs once.
2. An excessive misfiring rate (approximately 20 to 50 misfires per 1000 crankshaft revolutions) occurs a total of 4 times.

The ECM flashes the MIL and sets a DTC when either one of the following conditions, which could cause the three-way catalytic converter damage, is detected (2 trip detection logic).

1. At a high engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs once.
2. At a normal engine rpm, a catalyst damage misfire, which monitored every 200 crankshaft revolutions, occurs 3 times.

HINT

If a catalyst damage misfire occurs, the ECM informs the driver by flashing the MIL.

A flat type knock sensor (non-resonant type) has a structure that can detect vibrations over a wide band of frequencies: between approximately 6 kHz and 15 kHz.

Knock sensors are fitted onto the engine block to detect engine knocking.

The knock sensor contains a piezoelectric element which generates a voltage if it becomes deformed.

The voltage is generated when the engine block vibrates due to knocking. Any occurrence of engine knocking can be suppressed by delaying the ignition timing.

HINT

When any of DTCs P0327, P0328, P0332 and P0333 are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is delayed to its maximum retardation. Fail-safe mode continues until the ignition switch is turned off.

Reference: Inspection using an oscilloscope

Scheme 131

The correct waveform is as shown.

The knock sensor, located on the cylinder block, detects spark knock. When spark knock occurs, the piezoelectric element of the sensor vibrates. When the ECM detects a voltage in this frequency range, it retards the ignition timing to suppress spark knock.

The ECM also senses background engine noise with the knock sensor and uses this noise to check for faults in the sensor. If the knock sensor signal level is too low for more than 10 seconds, or if the knock sensor output voltage is outside the normal range, the ECM interprets this as a fault in the knock sensor and sets a DTC.

A flat type knock sensor (non-resonant type) has a structure that can detect vibrations over a wide band of frequencies: between approximately 6 kHz and 15 kHz.

Knock sensors are fitted onto the engine block to detect engine knocking.

The knock sensor contains a piezoelectric element which generates a voltage if it becomes deformed.

The voltage is generated when the engine block vibrates due to knocking. Any occurrence of engine knocking can be suppressed by delaying the ignition timing.

HINT

When any of DTCs P0327, P0328, P0332 and P0333 are set, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is delayed to its maximum retardation. Fail-safe mode continues until the ignition switch is turned off.

Reference: Inspection using an oscilloscope

The correct waveform is as shown.

The knock sensor, located on the cylinder block, detects spark knock. When spark knock occurs, the piezoelectric element of the sensor vibrates. When the ECM detects a voltage in this frequency range, it retards the ignition timing to suppress spark knock.

The ECM also senses background engine noise with the knock sensor and uses this noise to check for faults in the sensor. If the knock sensor signal level is too low for more than 10 seconds, or if the knock sensor output voltage is outside the normal range, the ECM interprets this as a fault in the knock sensor and sets a DTC.

The crankshaft position (CKP) sensor system consists of a crankshaft position sensor plate and a magnetic coil.

The sensor plate has 34 teeth and is installed on the crankshaft. The pickup coil is made of windings, an iron core and magnet. The sensor plate rotates and as each tooth passes through the pickup coil, a pulse signal is created. The pickup coil generates 34 signals for each engine revolution. Based on these signals, the ECM calculates the crankshaft position and engine RPM. Using these calculations, the fuel injection time and ignition time are controlled.

Scheme 132

1. Reference: Inspection using an oscilloscope. HINT: The correct waveform is as shown. VV1+ and VV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminal Name Between VV1+ and VV1-, VV2+ and VV2- Between NE+ and NE- Tester Range 5 V/DIV, 20 ms./DIV. Condition Idling with warm engine

If there is no signal from the crankshaft position sensor despite the engine revolving, the ECM interprets this as a malfunction of the sensor.

If the malfunction is not repaired successfully, these DTCs are set 10 seconds after the engine is next started.

The crankshaft position (CKP) sensor system consists of a crankshaft position sensor plate and a magnetic coil.

The sensor plate has 34 teeth and is installed on the crankshaft. The pickup coil is made of windings, an iron core and magnet. The sensor plate rotates and as each tooth passes through the pickup coil, a pulse signal is created. The pickup coil generates 34 signals for each engine revolution. Based on these signals, the ECM calculates the crankshaft position and engine RPM. Using these calculations, the fuel injection time and ignition time are controlled.

1. Reference: Inspection using an oscilloscope. HINT: The correct waveform is as shown. VV1+ and VV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminal Name Between VV1+ and VV1-, VV2+ and VV2- Between NE+ and NE- Tester Range 5 V/DIV, 20 ms./DIV. Condition Idling with warm engine

If there is no signal from the crankshaft position sensor despite the engine revolving, the ECM interprets this as a malfunction of the sensor.

If the malfunction is not repaired successfully, these DTCs are set 10 seconds after the engine is next started.

The intake camshaft's Variable Valve Timing (VVT) sensor (VV1, VV2 signal) consists of a magnet and MRE (Magnetic Resistance Element).

The VVT camshaft drive gear has a sensor plate with 3 teeth on its outer circumference. When the gear rotates, changes occur in the air gaps between the sensor plate and MRE, which affects the magnetic field. As a result, the resistance of the MRE material fluctuates. The VVT sensor converts the gear rotation data to pulse signals, uses the pulse signals to determine the camshaft angle, and sends it to the ECM.

The crankshaft angle sensor plate has 34 teeth. The pickup coil generates 34 signals for each engine revolution. Based on combination of the VVT signals and NE signal, the ECM detects the crankshaft angle. Then the ECM uses this data to control fuel injection time and injection timing. Also, based on the NE signal, the ECM detects the engine speed.

1. Reference: Inspection using an oscilloscope HINT: The correct waveform is as shown. VV1+ and VV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminal Name Between VV1+ and VV1-, VV2+ and VV2- Between NE+ and NE- Tester Range 5 V/DIV. 20 ms./DIV. Condition Idling with warm engine

If no signal is transmitted by the VVT sensor despite the engine revolving, or the rotations of the camshaft and the crankshaft are not synchronized, the ECM interprets this as a malfunction of the sensor.

The intake camshaft's Variable Valve Timing (VVT) sensor (VV1, VV2 signal) consists of a magnet and MRE (Magnetic Resistance Element).

The VVT camshaft drive gear has a sensor plate with 3 teeth on its outer circumference. When the gear rotates, changes occur in the air gaps between the sensor plate and MRE, which affects the magnetic field. As a result, the resistance of the MRE material fluctuates. The VVT sensor converts the gear rotation data to pulse signals, uses the pulse signals to determine the camshaft angle, and sends it to the ECM.

The crankshaft angle sensor plate has 34 teeth. The pickup coil generates 34 signals for each engine revolution. Based on combination of the VVT signals and NE signal, the ECM detects the crankshaft angle. Then the ECM uses this data to control fuel injection time and injection timing. Also, based on the NE signal, the ECM detects the engine speed.

1. Reference: Inspection using an oscilloscope HINT: The correct waveform is as shown. VV1+ and VV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminal Name Between VV1+ and VV1-, VV2+ and VV2- Between NE+ and NE- Tester Range 5 V/DIV. 20 ms./DIV. Condition Idling with warm engine

If no signal is transmitted by the VVT sensor despite the engine revolving, or the rotations of the camshaft and the crankshaft are not synchronized, the ECM interprets this as a malfunction of the sensor.

HINT

1. These DTCs indicate malfunctions relating to the primary circuit.
2. If DTC P0351 is set, check the No. 1 ignition coil circuit.
3. If DTC P0352 is set, check the No. 2 ignition coil circuit.
4. If DTC P0353 is set, check the No. 3 ignition coil circuit.
5. If DTC P0354 is set, check the No. 4 ignition coil circuit.
6. If DTC P0355 is set, check the No. 5 ignition coil circuit.
7. If DTC P0356 is set, check the No. 6 ignition coil circuit.

A Direct Ignition System (DIS) is used on this vehicle.

The DIS is a 1-cylinder ignition system in which each cylinder is ignited by one ignition coil and spark plug is connected to the end of each secondary wiring. A powerful voltage, generated in the secondary wiring, is applied directly to each spark plug. The sparks of the spark plugs pass from the center electrode to the ground electrodes.

The ECM determines the ignition timing and transmits the ignition signals (IGT) to each cylinder. Using the IGT signal, the ECM turns the power transistor inside the igniter on and off. The power transistor, in turn, switches on and off the current to the primary coil. When the current to the primary coil is cut off, a powerful voltage is generated in the secondary coil. This voltage is applied to the spark plugs, causing them to spark inside the cylinders. As the ECM cuts the current to the primary coil off, the igniter sends back an ignition confirmation signal (IGF) to the ECM, for each cylinder ignition.

Scheme 133

Scheme 134

1. Reference: Inspection using an oscilloscope.
2. While cranking or idling the engine, check the waveform between terminals IGT (1 to 6) and E1, and IGF1, IGF1 and E1 of the ECM connector. Item Content ECM Terminal Name (1) Between IGT (1 to 6) and E1 (2) Between IGF1 and E1 Tester Range 2 V/DIV. 20 ms./DIV. Condition Idling with warm engine

Scheme 135

If the ECM does not receive any IGF signals despite transmitting the IGT signals, it interprets this as a fault in the igniter and sets a DTC.

If the malfunction is not repaired successfully, a DTC is set 1 second after the engine is next started.

HINT

1. These DTCs indicate malfunctions relating to the primary circuit.
2. If DTC P0351 is set, check the No. 1 ignition coil circuit.
3. If DTC P0352 is set, check the No. 2 ignition coil circuit.
4. If DTC P0353 is set, check the No. 3 ignition coil circuit.
5. If DTC P0354 is set, check the No. 4 ignition coil circuit.
6. If DTC P0355 is set, check the No. 5 ignition coil circuit.
7. If DTC P0356 is set, check the No. 6 ignition coil circuit.

A Direct Ignition System (DIS) is used on this vehicle.

The DIS is a 1-cylinder ignition system in which each cylinder is ignited by one ignition coil and spark plug is connected to the end of each secondary wiring. A powerful voltage, generated in the secondary wiring, is applied directly to each spark plug. The sparks of the spark plugs pass from the center electrode to the ground electrodes.

The ECM determines the ignition timing and transmits the ignition signals (IGT) to each cylinder. Using the IGT signal, the ECM turns the power transistor inside the igniter on and off. The power transistor, in turn, switches on and off the current to the primary coil. When the current to the primary coil is cut off, a powerful voltage is generated in the secondary coil. This voltage is applied to the spark plugs, causing them to spark inside the cylinders. As the ECM cuts the current to the primary coil off, the igniter sends back an ignition confirmation signal (IGF) to the ECM, for each cylinder ignition.

1. Reference: Inspection using an oscilloscope.
2. While cranking or idling the engine, check the waveform between terminals IGT (1 to 6) and E1, and IGF1, IGF1 and E1 of the ECM connector. Item Content ECM Terminal Name (1) Between IGT (1 to 6) and E1 (2) Between IGF1 and E1 Tester Range 2 V/DIV. 20 ms./DIV. Condition Idling with warm engine

If the ECM does not receive any IGF signals despite transmitting the IGT signals, it interprets this as a fault in the igniter and sets a DTC.

If the malfunction is not repaired successfully, a DTC is set 1 second after the engine is next started.

The exhaust camshaft's Variable Valve Timing (VVT) sensor consists of a magnet and MRE (Magnetic Resistance Element).

The exhaust camshaft has a sensor plate with 3 teeth on its outer circumference.

When the exhaust camshaft rotates, changes occur in the air gaps between the 3 teeth and MRE, which affects the magnet. As a result, the resistance of the MRE material fluctuates. The VVT sensor converts the exhaust camshaft rotation data to pulse signals, uses the pulse signals to determine the camshaft angle, and sends it to the ECM.

1. HINT: The correct waveform is as shown. EV1+ and EV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminal Name EV1+ and EV1-, or EV2+ and EV2- Between NE+ and NE- Tester Range 5 V/DIV. 20 ms./DIV. Condition Idling with warm engine

If no signal is transmitted by the VVT sensor despite the engine revolving, or the rotations of the camshaft and the crankshaft are not synchronized, the ECM interprets this as a malfunction of the sensor.

The exhaust camshaft's Variable Valve Timing (VVT) sensor consists of a magnet and MRE (Magnetic Resistance Element).

The exhaust camshaft has a sensor plate with 3 teeth on its outer circumference.

When the exhaust camshaft rotates, changes occur in the air gaps between the 3 teeth and MRE, which affects the magnet. As a result, the resistance of the MRE material fluctuates. The VVT sensor converts the exhaust camshaft rotation data to pulse signals, uses the pulse signals to determine the camshaft angle, and sends it to the ECM.

Scheme 136

1. DTC No. DTC Detection Condition Trouble Area P0365 P0390 Missing exhaust VVT sensor signal for 5 seconds at engine speed of 600 rpm or more (1 trip detection logic) Open or short in VVT sensor for exhaust camshaft circuit VVT sensor for exhaust camshaft Exhaust camshaft ECM P0367 P0392 Output voltage of VVT sensor is less than 0.3 V for 4 seconds (1 trip detection logic) P0368 P0393 Output voltage of VVT sensor is more than 4.7 V for 4 seconds (1 trip detection logic) Reference: Inspection using an oscilloscope HINT: The correct waveform is as shown. EV1+ and EV2+ stand for the VVT sensor signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminal Name EV1+ and EV1-, or EV2+ and EV2- Between NE+ and NE- Tester Range 5 V/DIV. 20 ms./DIV. Condition Idling with warm engine

If no signal is transmitted by the VVT sensor despite the engine revolving, or the rotations of the camshaft and the crankshaft are not synchronized, the ECM interprets this as a malfunction of the sensor.

The ECM uses the sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the Air-Fuel Ratio (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This calculation is based on the voltage output of the HO2 sensor while performing active air- fuel ratio control, rather than the conventional detecting method, which uses the locus ratio.

The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven with a warm engine, active air-fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air-fuel ratio to lean or rich levels. If a rich-lean cycle of the HO2 sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and the TWC.

The ECM uses the OSC value to determine the state of the TWC. If any deterioration has occurred, it illuminates the MIL and sets a DTC.

HINT

1. Bank 1 refers to the bank that includes cylinder No. 1.
2. Bank 2 refers to the bank that does not include cylinder No. 1.
3. Sensor 1 refers to the sensor closest to the engine assembly.
4. Sensor 2 refers to the sensor farthest away from the engine assembly.

Scheme 137

The ECM uses the sensors mounted in front of and behind the Three-Way Catalytic Converter (TWC) to monitor its efficiency.

The first sensor, the Air-Fuel Ratio (A/F) sensor, sends pre-catalyst information to the ECM. The second sensor, the Heated Oxygen (HO2) sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the TWC, the ECM calculates the Oxygen Storage Capacity (OSC) of the TWC. This calculation is based on the voltage output of the HO2 sensor while performing active air- fuel ratio control, rather than the conventional detecting method, which uses the locus ratio.

The OSC value is an indication of the oxygen storage capacity of the TWC. When the vehicle is being driven with a warm engine, active air-fuel ratio control is performed for approximately 15 to 20 seconds. When it is performed, the ECM deliberately sets the air-fuel ratio to lean or rich levels. If a rich-lean cycle of the HO2 sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the HO2 sensor and the TWC.

The ECM uses the OSC value to determine the state of the TWC. If any deterioration has occurred, it illuminates the MIL and sets a DTC.

HINT

1. Bank 1 refers to the bank that includes cylinder No. 1.
2. Bank 2 refers to the bank that does not include cylinder No. 1.
3. Sensor 1 refers to the sensor closest to the engine assembly.
4. Sensor 2 refers to the sensor farthest away from the engine assembly.

The circuit description can be found in the EVAP (Evaporative Emission) System. Refer to DESCRIPTION.

5 hours *1 after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

HINT

*1 : If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.

*2 : If there is only a small amount of fuel in the fuel tank, stabilizing the EVAP pressure takes longer than usual.

Scheme 138

Scheme 139

The leak detection pump creates negative pressure through the reference orifice. When the system is normal, the EVAP pressure is in 724 to 752 mmHg * and saturated within a minute.

If not, the ECM interprets this as a malfunction. The ECM will illuminate the MIL and set a DTC if this malfunction is detected in consecutive drive cycle.

* : Typical valve

The circuit description can be found in the EVAP (Evaporative Emission) System. Refer to DESCRIPTION.

5 hours *1 after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

HINT

*1 : If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later.

*2 : If there is only a small amount of fuel in the fuel tank, stabilizing the EVAP pressure takes longer than usual.

The leak detection pump creates negative pressure through the reference orifice. When the system is normal, the EVAP pressure is in 724 to 752 mmHg * and saturated within a minute.

If not, the ECM interprets this as a malfunction. The ECM will illuminate the MIL and set a DTC if this malfunction is detected in consecutive drive cycle.

* : Typical valve

The circuit description can be found in the EVAP (Evaporative Emission) System. Refer to DESCRIPTION.

The two monitors, Key-off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The key-off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the ignition switch is turned off. The purge flow monitor runs while the engine is running.

Scheme 140

Scheme 141

Scheme 142

1. KEY-OFF MONITOR 5 hours*1 after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure. HINT: *1: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later. Sequence Operation Description Duration - ECM activation Activated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned off. - A Atmospheric pressure measurement Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to register atmospheric pressure. If pressure in EVAP system not between 70 kPa and 110 kPa (525 mmHg and 825 mmHg), ECM cancels EVAP system monitor. 60 seconds B First 0.02 inch leak pressure measurement In order to determine 0.02 inch leak pressure standard, leak detection pump creates negative pressure (vacuum) through 0.02 inch orifice and then ECM checks if leak detection pump and vent valve operate normally. 60 seconds C EVAP system pressure measurement Vent valve turned ON (closed) to shut EVAP system. Negative pressure (vacuum) created in EVAP system, and EVAP system pressure then measured. Write down measured value as they will be used in leak check. If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor. 15 minutes*2 D Purge VSV monitor Purge VSV opened and then EVAP system pressure measured by ECM. Large increase indicates normal. 10 seconds E Second 0.02 inch leak pressure measurement After second 0.02 inch leak pressure measurement, leak check performed by comparing first and second 0.02 inch leak pressure standards. If stabilized system pressure higher than second 0.02 inch leak pressure standard, ECM determines that EVAP system leaking. 60 seconds F Final check Atmospheric pressure measured and then monitoring result recorded by ECM. - HINT: *2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize. Purge VSV stuck open In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The EVAP system pressure is then measured by the ECM using the pressure sensor. If the stabilized system pressure is higher than [second 0.02 inch leak pressure standard x 0.2], the ECM interprets this as the Purge VSV (Vacuum Switching Valve) being stuck open. The ECM illuminates the MIL and sets the DTC (2 trip detection logic). Purge VSV stuck closed In operation D, the pressure sensor measures the EVAP (Evaporative Emission) system pressure. The pressure measurement for Purge VSV monitor is begun when the Purge VSV is turned ON (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa (2.25 mmHg) or more, the Purge VSV is functioning normally. If the pressure does not increase, the ECM interprets this as the Purge VSV being stuck closed. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
2. PURGE FLOW MONITOR The purge flow monitor consists of the two step monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary. The 1st monitor While the engine is running and the Purge VSV (Vacuum Switching Valve) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor. The 2nd monitor The vent valve is turned ON (closed) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.4 kPa (3.0 mmHg), the ECM interprets this as the Purge VSV being stuck closed, and illuminates the MIL and sets DTC P0441 (2 trip detection logic). Atmospheric pressure check: In order to ensure reliable malfunction detection, the variation between the atmospheric pressure, before and after conduction of the purge flow monitor, is measured by the ECM.

The circuit description can be found in the EVAP (Evaporative Emission) System. Refer to DESCRIPTION.

The two monitors, Key-off and Purge Flow, are used to detect malfunctions relating to DTC P0441. The key-off monitor is initiated by the ECM internal timer, known as the soak timer, 5 hours* after the ignition switch is turned off. The purge flow monitor runs while the engine is running.

1. KEY-OFF MONITOR 5 hours*1 after the ignition switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure. HINT: *1: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later. Sequence Operation Description Duration - ECM activation Activated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned off. - A Atmospheric pressure measurement Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to register atmospheric pressure. If pressure in EVAP system not between 70 kPa and 110 kPa (525 mmHg and 825 mmHg), ECM cancels EVAP system monitor. 60 seconds B First 0.02 inch leak pressure measurement In order to determine 0.02 inch leak pressure standard, leak detection pump creates negative pressure (vacuum) through 0.02 inch orifice and then ECM checks if leak detection pump and vent valve operate normally. 60 seconds C EVAP system pressure measurement Vent valve turned ON (closed) to shut EVAP system. Negative pressure (vacuum) created in EVAP system, and EVAP system pressure then measured. Write down measured value as they will be used in leak check. If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor. 15 minutes*2 D Purge VSV monitor Purge VSV opened and then EVAP system pressure measured by ECM. Large increase indicates normal. 10 seconds E Second 0.02 inch leak pressure measurement After second 0.02 inch leak pressure measurement, leak check performed by comparing first and second 0.02 inch leak pressure standards. If stabilized system pressure higher than second 0.02 inch leak pressure standard, ECM determines that EVAP system leaking. 60 seconds F Final check Atmospheric pressure measured and then monitoring result recorded by ECM. - HINT: *2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize. Purge VSV stuck open In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The EVAP system pressure is then measured by the ECM using the pressure sensor. If the stabilized system pressure is higher than [second 0.02 inch leak pressure standard x 0.2], the ECM interprets this as the Purge VSV (Vacuum Switching Valve) being stuck open. The ECM illuminates the MIL and sets the DTC (2 trip detection logic). Purge VSV stuck closed In operation D, the pressure sensor measures the EVAP (Evaporative Emission) system pressure. The pressure measurement for Purge VSV monitor is begun when the Purge VSV is turned ON (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa (2.25 mmHg) or more, the Purge VSV is functioning normally. If the pressure does not increase, the ECM interprets this as the Purge VSV being stuck closed. The ECM illuminates the MIL and sets the DTC (2 trip detection logic).
2. PURGE FLOW MONITOR The purge flow monitor consists of the two step monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary. The 1st monitor While the engine is running and the Purge VSV (Vacuum Switching Valve) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor. The 2nd monitor The vent valve is turned ON (closed) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.4 kPa (3.0 mmHg), the ECM interprets this as the Purge VSV being stuck closed, and illuminates the MIL and sets DTC P0441 (2 trip detection logic). Atmospheric pressure check: In order to ensure reliable malfunction detection, the variation between the atmospheric pressure, before and after conduction of the purge flow monitor, is measured by the ECM.

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• COMPONENTS