Engine Control System (Diagnostic Codes (P0128-P0420)): Overview Scion tC II рестайлинг

DESCRIPTION

This DTC is stored when the engine coolant temperature does not reach 75°C (167°F) despite sufficient engine warmup time having elapsed.

Scheme 125

The ECM estimates the engine coolant temperature based on the starting temperature, engine load and engine speed. The ECM then compares the estimated temperature with the actual engine coolant temperature. When the estimated engine coolant temperature reaches 75°C (167°F), the ECM checks the actual engine coolant temperature. If the actual engine coolant temperature is below 75°C (167°F), the ECM interprets this as a malfunction in the thermostat or the engine cooling system and stores the DTC.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a Three-way Catalytic Converter (TWC) is used. For the most efficient use of the Three-way Catalytic Converter (TWC), the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio. For the purpose of helping the ECM to deliver accurate air-fuel ratio control, a heated oxygen sensor is used.

The heated oxygen sensor is located behind the Three-way Catalytic Converter (TWC), and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with a 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 is rich. The heated oxygen sensor informs the ECM that the post-Three-way Catalytic Converter (TWC) air-fuel ratio is lean (low voltage, i.e. below 0.45 V).

Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel ratio, the oxygen concentration in the exhaust gas becomes lean. The heated oxygen sensor informs the ECM that the post-Three-way Catalytic Converter (TWC) air-fuel ratio is rich (high voltage, i.e. higher than 0.45 V). The heated oxygen 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 heated oxygen sensor to determine whether the air-fuel ratio after the Three-way Catalytic Converter (TWC) is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in primary air-fuel ratio control.

Scheme 126

MONITOR DESCRIPTION

Active Air-fuel Ratio Control

The ECM usually performs air-fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air-fuel ratio. 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 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, a DTC is stored.

Abnormal Voltage Output of Heated Oxygen Sensor (DTC P0136)

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 heated oxygen sensor voltage does not increase to a value higher than 0.69 V during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormal and stores DTC P0136.

Scheme 127

Open in Heated Oxygen Sensor Circuit (DTC P0137)

During active air fuel ratio control, the ECM calculates the oxygen storage capacity* of the three-way catalytic converter by forcibly regulating the air fuel ratio to become rich or lean.

If the heated oxygen sensor has an open circuit, or the voltage output of the sensor noticeably decreases, the oxygen storage capacity indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air-fuel ratio to become rich or lean, the heated oxygen sensor output does not change.

While performing active air fuel ratio control, when the target air fuel ratio is rich and the heated oxygen sensor voltage output is 0.21 V or less (lean), the ECM interprets this as an abnormally low sensor output voltage and stores DTC P0137.

HINT

*: The three-way catalytic converter has the capability to store oxygen. The oxygen storage capacity and the emission purification capacity of the three-way catalytic converter are mutually related. The ECM determines whether the catalyst has deteriorated based on the calculated oxygen storage capacity value. Refer to MONITOR DESCRIPTION.

Scheme 128

High or Low Impedance of Heated Oxygen Sensor (DTC P0136 or P0137)

Scheme 129

During normal air-fuel ratio feedback control, there are small variations in the exhaust gas oxygen concentration. In order to continuously monitor the slight variations in the heated oxygen 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

1. The impedance cannot be measured using an ohmmeter.
2. DTC P0136 indicates deterioration of the heated oxygen sensor. The ECM stores this DTC by calculating the impedance of the sensor when the typical enabling conditions are satisfied (2 driving cycles).
3. DTC P0137 indicates an open or short circuit in the heated oxygen sensor (2 driving cycles). The ECM stores this DTC when the impedance of the sensor exceeds the threshold of 15 kohms.

Extremely High Output Voltage of Heated Oxygen Sensor (DTC P0138)

The ECM continuously monitors the heated oxygen sensor output voltage while the engine is running.

DTC P0138 is stored if the heated oxygen sensor voltage output is higher than 1.2 V for 10 seconds or more.

Abnormal Voltage Output of Heated Oxygen Sensor During Fuel Cut (P0139)

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, the ECM determines that the sensor response has deteriorated, illuminates the MIL and stores a DTC.

Abnormal Voltage Output of Heated Oxygen Sensor during Fuel Cut from Rich Condition (DTC P013A)

If the sensor output voltage does not drop from 0.35 to 0.2 V immediately when the vehicle decelerates and fuel cut is operating, the ECM illuminates the MIL and stores a DTC.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a Three-way Catalytic Converter (TWC) is used. For the most efficient use of the Three-way Catalytic Converter (TWC), the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric air-fuel ratio. For the purpose of helping the ECM to deliver accurate air-fuel ratio control, a heated oxygen sensor is used.

The heated oxygen sensor is located behind the Three-way Catalytic Converter (TWC), and detects the oxygen concentration in the exhaust gas. Since the sensor is integrated with a 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 is rich. The heated oxygen sensor informs the ECM that the post-Three-way Catalytic Converter (TWC) air-fuel ratio is lean (low voltage, i.e. below 0.45 V).

Conversely, when the air-fuel ratio is richer than the stoichiometric air-fuel ratio, the oxygen concentration in the exhaust gas becomes lean. The heated oxygen sensor informs the ECM that the post-Three-way Catalytic Converter (TWC) air-fuel ratio is rich (high voltage, i.e. higher than 0.45 V). The heated oxygen 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 heated oxygen sensor to determine whether the air-fuel ratio after the Three-way Catalytic Converter (TWC) is rich or lean, and adjusts the fuel injection time accordingly. Thus, if the heated oxygen sensor is working improperly due to internal malfunctions, the ECM is unable to compensate for deviations in primary air-fuel ratio control.

Active Air-fuel Ratio Control

The ECM usually performs air-fuel ratio feedback control so that the air fuel ratio sensor output indicates a near stoichiometric air-fuel ratio. 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 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, a DTC is stored.

Abnormal Voltage Output of Heated Oxygen Sensor (DTC P0136)

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 heated oxygen sensor voltage does not increase to a value higher than 0.69 V during active air-fuel ratio control, the ECM determines that the sensor voltage output is abnormal and stores DTC P0136.

Open in Heated Oxygen Sensor Circuit (DTC P0137)

During active air fuel ratio control, the ECM calculates the oxygen storage capacity* of the three-way catalytic converter by forcibly regulating the air fuel ratio to become rich or lean.

If the heated oxygen sensor has an open circuit, or the voltage output of the sensor noticeably decreases, the oxygen storage capacity indicates an extraordinarily high value. Even if the ECM attempts to continue regulating the air-fuel ratio to become rich or lean, the heated oxygen sensor output does not change.

While performing active air fuel ratio control, when the target air fuel ratio is rich and the heated oxygen sensor voltage output is 0.21 V or less (lean), the ECM interprets this as an abnormally low sensor output voltage and stores DTC P0137.

HINT

*: The three-way catalytic converter has the capability to store oxygen. The oxygen storage capacity and the emission purification capacity of the three-way catalytic converter are mutually related. The ECM determines whether the catalyst has deteriorated based on the calculated oxygen storage capacity value. Refer to MONITOR DESCRIPTION.

High or Low Impedance of Heated Oxygen Sensor (DTC P0136 or P0137)

During normal air-fuel ratio feedback control, there are small variations in the exhaust gas oxygen concentration. In order to continuously monitor the slight variations in the heated oxygen 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

1. The impedance cannot be measured using an ohmmeter.
2. DTC P0136 indicates deterioration of the heated oxygen sensor. The ECM stores this DTC by calculating the impedance of the sensor when the typical enabling conditions are satisfied (2 driving cycles).
3. DTC P0137 indicates an open or short circuit in the heated oxygen sensor (2 driving cycles). The ECM stores this DTC when the impedance of the sensor exceeds the threshold of 15 kohms.

Extremely High Output Voltage of Heated Oxygen Sensor (DTC P0138)

The ECM continuously monitors the heated oxygen sensor output voltage while the engine is running.

DTC P0138 is stored if the heated oxygen sensor voltage output is higher than 1.2 V for 10 seconds or more.

Abnormal Voltage Output of Heated Oxygen Sensor During Fuel Cut (P0139)

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, the ECM determines that the sensor response has deteriorated, illuminates the MIL and stores a DTC.

Abnormal Voltage Output of Heated Oxygen Sensor during Fuel Cut from Rich Condition (DTC P013A)

If the sensor output voltage does not drop from 0.35 to 0.2 V immediately when the vehicle decelerates and fuel cut is operating, the ECM illuminates the MIL and stores a DTC.

HINT

1. Refer to DTC P2195. Refer to «DESCRIPTION»(/scion/tc/ii-2013-2016/remont/testing-diagnostics/#engine-control-system-diagnostic-codes-p1604-u0101) .
2. Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.

*: Calculated by the ECM based on the air fuel ratio sensor output

After the engine is warm, the ECM carries out air-fuel ratio feedback control, and maintains the air-fuel ratio at the stoichiometric 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 air fuel ratio sensor by increasing or decreasing the injection volume by a specific quantity based on the stoichiometric air-fuel ratio learned during normal air-fuel control. The ECM determines whether there is an air fuel ratio sensor malfunction at the mid-point of active air-fuel ratio control.

If the air fuel ratio sensor's response ability is reduced, DTC P014C and P014D are stored.

If the time it takes the air fuel ratio sensor output to change is delayed, DTC P015A and P015B are stored.

Scheme 130

HINT

1. Refer to DTC P2195. Refer to «DESCRIPTION»(/scion/tc/ii-2013-2016/remont/testing-diagnostics/#engine-control-system-diagnostic-codes-p1604-u0101) .
2. Sensor 1 refers to the sensor mounted in front of the three-way catalytic converter and located near the engine assembly.

*: Calculated by the ECM based on the air fuel ratio sensor output

After the engine is warm, the ECM carries out air-fuel ratio feedback control, and maintains the air-fuel ratio at the stoichiometric 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 air fuel ratio sensor by increasing or decreasing the injection volume by a specific quantity based on the stoichiometric air-fuel ratio learned during normal air-fuel control. The ECM determines whether there is an air fuel ratio sensor malfunction at the mid-point of active air-fuel ratio control.

If the air fuel ratio sensor's response ability is reduced, DTC P014C and P014D are stored.

If the time it takes the air fuel ratio sensor output to change is delayed, DTC P015A and P015B are stored.

The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the 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 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 and 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 vary 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.

HINT

1. When DTC P0171 is stored, the actual air-fuel ratio is on the lean side. When DTC P0172 is stored, 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 may be stored. 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 higher 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 estimated fuel injection volumes also affect the average fuel trim learned value, which is a combination of the average short-term fuel trim (fuel feedback compensation value) and the average long-term fuel trim (learned value of the air-fuel ratio). If the average fuel trim learned value exceeds the malfunction threshold, the ECM interprets this as a fault in the fuel system and stores a DTC.

Example

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

Scheme 131

The fuel trim is related to the feedback compensation value, not to the basic injection time. The fuel trim consists of both the 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 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 and 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 vary 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.

HINT

1. When DTC P0171 is stored, the actual air-fuel ratio is on the lean side. When DTC P0172 is stored, 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 may be stored. 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 higher 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 estimated fuel injection volumes also affect the average fuel trim learned value, which is a combination of the average short-term fuel trim (fuel feedback compensation value) and the average long-term fuel trim (learned value of the air-fuel ratio). If the average fuel trim learned value exceeds the malfunction threshold, the ECM interprets this as a fault in the fuel system and stores a DTC.

Example

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

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

1. Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 40 to 60 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 (immediate detection logic) and sets a DTC (2 trip detection logic) when either one of the following conditions, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected

1. At a high engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected once.
2. At a normal engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.

TEXT IN ILLUSTRATION

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high HC concentration levels can cause increases in exhaust emissions levels. High concentrations of HC can also cause increases in the Three-way Catalytic Converter (TWC) temperature, which may cause damage to the Three-way Catalytic Converter (TWC). To prevent these increases 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 (TWC) reaches the point of thermal degradation, the MIL blinks. To monitor misfires, the ECM uses both the camshaft position sensor and the crankshaft position sensor. The camshaft position 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 as when the crankshaft rotation speed variations exceed predetermined thresholds.

If the misfire rate exceeds the threshold, the ECM illuminates the MIL and stores a DTC.

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

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

1. Within the first 1000 crankshaft revolutions of the engine starting, an excessive misfiring rate (approximately 40 to 60 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 (immediate detection logic) and sets a DTC (2 trip detection logic) when either one of the following conditions, which could cause the Three-Way Catalytic Converter (TWC) damage, is detected

1. At a high engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected once.
2. At a normal engine speed, a sufficient amount of misfires to damage the catalyst occurring within 200 crankshaft revolutions is detected 3 times.

A flat-type knock sensor (non-resonant type) has a structure that can detect vibrations between approximately 5 kHz and 15 kHz.

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

Each knock sensor contains a piezoelectric element which generates a voltage when 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 DTC P0327 or P0328 is stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is delayed to its maximum retardation. The ECM continues operating in fail-safe mode until the ignition switch is turned off.

Reference: Inspection using an oscilloscope

Scheme 132

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 the 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 output voltage is outside the normal range, the ECM interprets this as a fault in the knock sensor and stores a DTC.

A flat-type knock sensor (non-resonant type) has a structure that can detect vibrations between approximately 5 kHz and 15 kHz.

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

Each knock sensor contains a piezoelectric element which generates a voltage when 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 DTC P0327 or P0328 is stored, the ECM enters fail-safe mode. During fail-safe mode, the ignition timing is delayed to its maximum retardation. The ECM continues operating in fail-safe mode until the ignition switch is turned off.

Reference: Inspection using an oscilloscope

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 the 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 output voltage is outside the normal range, the ECM interprets this as a fault in the knock sensor and stores a DTC.

The crankshaft position sensor system consists of a crankshaft position sensor plate and a pickup coil.

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

Scheme 133

1. Reference: Inspection using an oscilloscope. HINT: G2 stands for the camshaft position sensor signal, NE stands for the crankshaft position sensor signal and EV1 stands for the camshaft position sensor (for exhaust side) signal. Grounding failure of the shielded wire may cause noise in the waveforms. Tester Connection Tool Setting Condition Specified Condition B30-74 (NE+) - B30-120 (NE-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-76 (G2+) - B30-122 (G2-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-75 (EV1+) - B30-121 (EV1-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown

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

If the malfunction is not repaired successfully, a DTC is stored 10 seconds after the engine is next started.

The crankshaft position sensor system consists of a crankshaft position sensor plate and a pickup coil.

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

1. Reference: Inspection using an oscilloscope. HINT: G2 stands for the camshaft position sensor signal, NE stands for the crankshaft position sensor signal and EV1 stands for the camshaft position sensor (for exhaust side) signal. Grounding failure of the shielded wire may cause noise in the waveforms. Tester Connection Tool Setting Condition Specified Condition B30-74 (NE+) - B30-120 (NE-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-76 (G2+) - B30-122 (G2-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-75 (EV1+) - B30-121 (EV1-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown

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

If the malfunction is not repaired successfully, a DTC is stored 10 seconds after the engine is next started.

The intake camshaft position sensor (G2 signal) consists of a magnet and MRE (Magnetoresistive Element).

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

The crankshaft position sensor plate has 34 teeth. The MRE generates 34 signals for each crankshaft revolution. Based on a combination of the G2 signal 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: G2 stands for the camshaft position sensor (for intake side) signal, NE stands for the crankshaft position sensor signal and EV1 stands for the camshaft position sensor (for exhaust side) signal. Grounding failure of the shielded wire may cause noise in waveforms. Tester Connection Tool Setting Condition Specified Condition B30-74 (NE+) - B30-120 (NE-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-76 (G2+) - B30-122 (G2-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-75 (EV1+) - B30-121 (EV1-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown

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

Also, when the sensor output voltage remains below 0.3 V, or higher than 4.7 V for more than 4 seconds, the ECM stores a DTC.

The intake camshaft position sensor (G2 signal) consists of a magnet and MRE (Magnetoresistive Element).

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

The crankshaft position sensor plate has 34 teeth. The MRE generates 34 signals for each crankshaft revolution. Based on a combination of the G2 signal 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: G2 stands for the camshaft position sensor (for intake side) signal, NE stands for the crankshaft position sensor signal and EV1 stands for the camshaft position sensor (for exhaust side) signal. Grounding failure of the shielded wire may cause noise in waveforms. Tester Connection Tool Setting Condition Specified Condition B30-74 (NE+) - B30-120 (NE-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-76 (G2+) - B30-122 (G2-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-75 (EV1+) - B30-121 (EV1-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown

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

Also, when the sensor output voltage remains below 0.3 V, or higher than 4.7 V for more than 4 seconds, the ECM stores a DTC.

HINT

1. These DTCs indicate malfunctions relating to the primary circuit.
2. If DTC P0351 is stored, check the No. 1 ignition coil circuit.
3. If DTC P0352 is stored, check the No. 2 ignition coil circuit.
4. If DTC P0353 is stored, check the No. 3 ignition coil circuit.
5. If DTC P0354 is stored, check the No. 4 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 one 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 (IGT) signals 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, the igniter sends back an ignition confirmation (IGF) signal to the ECM for each cylinder ignition.

Scheme 134

1. Reference: Inspection using an oscilloscope.
2. Tester Connection Tool Setting Condition Specified Condition B30-108 (IGT1) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-107 (IGT2) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-106 (IGT3) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-105 (IGT4) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-23 (IGF1) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown HINT: While cranking or idling the engine, check the waveform between terminals IGT (1 to 4) and E1, and IGF1 and E1 of the ECM connector.

Scheme 135

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

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

HINT

1. These DTCs indicate malfunctions relating to the primary circuit.
2. If DTC P0351 is stored, check the No. 1 ignition coil circuit.
3. If DTC P0352 is stored, check the No. 2 ignition coil circuit.
4. If DTC P0353 is stored, check the No. 3 ignition coil circuit.
5. If DTC P0354 is stored, check the No. 4 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 one 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 (IGT) signals 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, the igniter sends back an ignition confirmation (IGF) signal to the ECM for each cylinder ignition.

1. Reference: Inspection using an oscilloscope.
2. Tester Connection Tool Setting Condition Specified Condition B30-108 (IGT1) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-107 (IGT2) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-106 (IGT3) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-105 (IGT4) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown B30-23 (IGF1) - B30-104 (E1) 2 V/DIV., 20 msec./DIV. Idling The correct waveform is as shown HINT: While cranking or idling the engine, check the waveform between terminals IGT (1 to 4) and E1, and IGF1 and E1 of the ECM connector.

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

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

The exhaust camshaft position sensor (EV1 signal) consists of a magnet and MRE (Magnetoresistive Element).

The exhaust camshaft has 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 magnetic field. As a result, the resistance of the MRE fluctuates. The camshaft position sensor converts the exhaust camshaft rotation data into pulse signals, uses the pulse signals to determine the camshaft angle, and sends the data to the ECM.

1. Reference: Inspection using an oscilloscope. HINT: G2 stands for the camshaft position sensor (for exhaust side) signal, NE stands for the crankshaft position sensor signal and EV1 stands for the camshaft position sensor (for exhaust side) signal. Grounding failure of the shielded wire may cause noise in waveforms. Tester Connection Tool Setting Condition Specified Condition B30-74 (NE+) - B30-120 (NE-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-76 (G2+) - B30-122 (G2-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-75 (EV1+) - B30-121 (EV1-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown

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

Also, when the sensor output voltage remains below 0.3 V, or higher than 4.7 V for more than 4 seconds, the ECM stores a DTC.

The exhaust camshaft position sensor (EV1 signal) consists of a magnet and MRE (Magnetoresistive Element).

The exhaust camshaft has 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 magnetic field. As a result, the resistance of the MRE fluctuates. The camshaft position sensor converts the exhaust camshaft rotation data into pulse signals, uses the pulse signals to determine the camshaft angle, and sends the data to the ECM.

1. Reference: Inspection using an oscilloscope. HINT: G2 stands for the camshaft position sensor (for exhaust side) signal, NE stands for the crankshaft position sensor signal and EV1 stands for the camshaft position sensor (for exhaust side) signal. Grounding failure of the shielded wire may cause noise in waveforms. Tester Connection Tool Setting Condition Specified Condition B30-74 (NE+) - B30-120 (NE-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-76 (G2+) - B30-122 (G2-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown B30-75 (EV1+) - B30-121 (EV1-) 5 V/DIV, 20 ms/DIV Idling The correct waveform is as shown

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

Also, when the sensor output voltage remains below 0.3 V, or higher than 4.7 V for more than 4 seconds, the ECM stores a DTC.

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

The first sensor, the air fuel ratio sensor, sends pre-catalyst information to the ECM. The second sensor, the heated oxygen sensor, sends post-catalyst information to the ECM.

In order to detect any deterioration in the Three-way Catalytic Converter (TWC), the ECM calculates the Oxygen Storage Capacity (OSC) of the Three-way Catalytic Converter (TWC). This calculation is based on the voltage output of the heated oxygen sensor while performing active air-fuel ratio control.

The OSC value is an indication of the oxygen storage capacity of the Three-way Catalytic Converter (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 the rich-lean cycle of the heated oxygen sensor is long, the OSC becomes greater. There is a direct correlation between the OSC of the heated oxygen sensor and OSC of Three-way Catalytic Converter (TWC).

The ECM uses the OSC value to determine the state of the Three-way Catalytic Converter (TWC). If any deterioration has occurred, it illuminates the MIL and stores the DTC.

Scheme 136

TEXT IN ILLUSTRATION

Note. Replace the exhaust manifold converter sub-assembly (*1) and the center exhaust pipe assembly (*3) together when catalyst replacement is necessary. (Excluding air fuel ratio sensor *5 and heated oxygen sensor *6)

See also:
• DESCRIPTION
• ON-VEHICLE INSPECTION [05/2013 - ] - Step 2
• ON-VEHICLE INSPECTION [05/2013 - ] - Step 1
• ON-VEHICLE INSPECTION [05/2013 - ] - Step 1