Engine Control System (Diagnostic Codes (P0190-P0617)): Overview Lexus IS II facelift 2

DESCRIPTION

The fuel pressure sensor is installed on the delivery pipe. The sensor changes fuel pressure to an electrical signal and sends the signal to the ECM. Then the ECM controls the feedback of the pump discharge to maintain the fuel's target pressure between 4000 and 13000 kPa (40.8 and 132.6 kgf/cm, 580 and 1886 psi). If the sensor output stops, the ECM will stop the high pressure side fuel pump and supply fuel using the low pressure side fuel pump.

Scheme 124

HINT

After confirming DTC P0190, use Techstream to confirm the fuel pressure in the delivery pipe by following menus Powertrain / Engine / Data List / Fuel Press.

MONITOR DESCRIPTION

These DTCs are set if the fuel pressure sensor output voltage is out of the standard range. The DTCs stand for an open or short malfunction of the sensor circuit.

If these DTCs are set, the ECM enters fail-safe mode and limits the engine power. Fail-safe mode continues until the engine switch is turned off.

The high speed activation of the high pressure fuel injector is possible through the high-voltage, rapid-recharge DC/DC converter. Using high pressure fuel, the atomized fuel's injection timing can be accurately controlled, which decreases emissions and fuel consumption. The steady ECM checks the injector driver movement. When the injector driver or injector has a malfunction, the injection control of the relevant cylinder is stopped or power to the injector relay is cut. Then the ECM illuminates the check engine warning light.

When the engine is cranked, a signal is sent from the ignition control ECU's STSW terminal to the ECM's STSW terminal. Then voltage travels from the ECM's STAR terminal through the park/neutral position switch to the STARTER relay coil. The STAR terminal also sends a signal to the STA terminal. When the STA signal and NE signal are input to the ECM, the ECM interior's Tr1 turns on, which causes power to be supplied to the C/OPN relay coil (C/OPN on). As a result, the F/PMP relay actuates, which causes the fuel pump to operate. If the engine is operating and NE signals are being output, the ECM interior's Tr1 is on (C/OPN on), and the fuel pump will continue operating. The fuel pump's has a high and low speed setting. When the engine is starting or operating with a heavy load, the ECM interior's Tr2 turns off so that the F/PMP relay will close and the fuel pump will operates at the high speed setting. When the engine is idling or operating with a light load, the Tr2 turns on, operating the F/PMP relay and causing current to flows through the fuel pump resistor to the fuel pump. This operates the fuel pump at the low speed setting.

Scheme 125

When the engine misfires, high concentrations of hydrocarbons (HC) enter the exhaust gas. Extremely high hydrocarbons concentration levels can cause increases in exhaust emission levels. 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 these increases in emissions and to limit the possibility of thermal damage, the ECM monitors the misfire count. 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 level and could cause emission deterioration, the ECM illuminates the MIL and sets a DTC.

When DTCs for misfiring cylinders are randomly 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.

1. 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). 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. After the first 1000 crankshaft revolutions, an excessive misfiring rate (approximately 20 to 60 misfires per 1000 crankshaft revolutions) occurs 4 times in sequential crankshaft revolutions.

1. The ECM flashes the MIL (immediately 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 damage, is detected. In every 200 crankshaft revolutions at a high engine speed, the threshold misfiring percentage is recorded once. In every 200 crankshaft revolutions at a normal engine speed, the threshold misfiring percentage is recorded 3 times.

A flat type knock sensor (non-resonant type) has a structure that can detect vibrations over a wide band of frequencies: between approximately 5 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 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 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 engine switch is turned off.

Reference: Inspection using an oscilloscope

Scheme 126

The correct waveform is as shown.

If the output voltage transmitted by the knock control sensor remains low or high 1 second or more, the ECM interprets this as a malfunction in the sensor circuit, and stores a DTC.

The monitor for DTCs P0327, P0328, P0332 and P0333 begins to run when 5 seconds have elapsed since the engine was started.

The crankshaft position (CKP) 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 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 speed. Using these calculations, the fuel injection time and ignition time are controlled.

Scheme 127

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

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

The VVT sensor (for intake camshaft) (VV1, VV2 signal) consists of a magnet and MRE (Magneto Resistance Element).

The camshaft timing gear assembly has a sensor plate for the VVT sensor. When the intake camshaft rotates, changes occur in the air gaps between the timing rotor and MRE, which affects the magnetic field. As a result, the resistance of the MRE material fluctuates. The VVT sensor converts the intake camshaft rotation data to pulse signals, uses the pulse signals to determine the camshaft angle, and sends it to the ECM.

Then the ECM uses this data to control fuel injection duration, fuel injection timing and Variable Valve Timing (VVT) system.

Scheme 128

1. Reference: Inspection using an oscilloscope

HINT

1. The correct waveform is as shown.
2. VV1+ and VV2+ stand for the VVT sensor for intake camshaft signal, and NE+ stands for the CKP sensor signal.

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, the igniter sends back an ignition confirmation signal (IGF) to the ECM, for each cylinder ignition.

Scheme 129

Scheme 130

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, IGF2 and E1 of the ECM connector. Item Content ECM Terminals Name CH1: IGT1, IGT3 or IGT5 - E1 CH2: IGF1 - E1 CH1: IGT2, IGT4 or IGT6 - E1 CH2: IGF2 - E1 Tester Range 2 V/DIV. 20 ms./DIV. Conditions Idling

Scheme 131

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

The VVT sensor (for exhaust camshaft) (EV1, EV2 signal) consists of a magnet and MRE (Magneto Resistance Element).

The exhaust camshaft has a timing rotor for the VVT sensor. When the exhaust camshaft rotates, changes occur in the air gaps between the timing rotor and MRE, which affects the magnetic field. 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.

Then the ECM uses this data to control fuel injection duration, fuel injection timing and the Variable Valve Timing (VVT) system.

Scheme 132

1. Reference: Inspection using an oscilloscope HINT: The correct waveform is as shown. EV1+ and EV2+ stand for the VVT sensor for exhaust camshaft signal, and NE+ stands for the CKP sensor signal. Item Content ECM Terminals Name Between NE+ and NE- Between EV1+ and EV1- or EV2+ and EV2- Tester Range 5 V/DIV. 20 ms./DIV. Condition Idling

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

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, the ECM calculates the oxygen storage capacity of the three-way catalytic converter. This calculation is based on the voltage output of the heated oxygen sensor while performing active air fuel ratio control.

The oxygen storage capacity value is an indication of the oxygen storage capacity of the three-way catalytic converter. 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 cycle of the waveform for the heated oxygen sensor is long, the oxygen storage capacity is great. There is a direct correlation between the heated oxygen sensor and the oxygen storage capacity of the three-way catalytic converter.

The ECM uses the oxygen storage capacity value to determine the state of the three-way catalytic converter. If any deterioration has occurred, the ECM illuminates the MIL and sets the DTC.

This system determines the deterioration of the entire catalyst system (including the front and rear catalysts), by using the oxygen storage capacity value of the front catalyst, that is more sensitive than the rear catalyst, as the representative value. Therefore, be sure to replace the front and rear catalysts together when catalyst replacement is necessary.

Scheme 133

Note. When outputting DTC P0420 replace the exhaust manifold sub-assembly RH and the front exhaust pipe assembly together when catalyst replacement is necessary (Excluding air fuel ratio sensor and heated oxygen sensor). When outputting DTC P0430 replace the exhaust manifold sub-assembly LH and the front exhaust pipe assembly together when catalyst replacement is necessary (Excluding air fuel ratio sensor and heated oxygen sensor).

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

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

HINT

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

*: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

Scheme 134

The leak detection pump creates negative pressure through the reference orifice (in operation B and E). When the system is normal, the EVAP pressure is between 97 to 100 kPa(abs) [728 to 750 mmHg(abs)]* and saturated within a minute. If not, the ECM interprets this as a malfunction. The ECM illuminates the MIL and stores a DTC if this malfunction is detected in consecutive drive cycles.

*: Typical value.

Scheme 135

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

The 2 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 engine switch is turned off. The purge flow monitor runs while the engine is running.

Scheme 136

Scheme 137

Scheme 138

1. KEY-OFF MONITOR 5 hours* after the engine switch is turned off, the electric 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: *: If the engine coolant temperature is not less than 35°C (95°F) 5 hours after the engine switch is turned off, the monitor check starts 2 hours later. If it is still not less than 35°C (95°F) 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later. Sequence Operation Description Duration - ECM activation Activated by soak timer 5, 7 or 9.5 hours after engine switch turned off. - A Atmospheric pressure measurement Vent valve is turned off (vent) and EVAP system pressure is measured by ECM in order to register atmospheric pressure. If pressure in EVAP system is not between 70 kPa(abs) and 110 kPa(abs) [525 mmHg(abs) and 825 mmHg(abs)], ECM cancels EVAP system monitor. 60 seconds B First reference pressure measurement In order to determine reference pressure, leak detection pump creates negative pressure (vacuum) through reference orifice and then ECM checks if leak detection pump and vent valve operate normally. 60 seconds C EVAP system pressure measurement Vent valve is turned on (closed) to shut EVAP system. Negative pressure (vacuum) is created in EVAP system, and EVAP system pressure is then measured. Write down measured value as it will be used in leak check. If EVAP pressure does not stabilize within 15 minutes, ECM cancels EVAP system monitor. 15 minutes* D Purge VSV monitor Purge VSV opened and then EVAP system pressure is measured by ECM. A large increase indicates normality. 10 seconds E Second reference pressure measurement After second reference pressure measurement, leak check is performed by comparing first and second reference pressure measurements. If stabilized system pressure is higher than second reference pressure, ECM determines that EVAP system leaking. 60 seconds - Final check Atmospheric pressure is measured and then monitoring result is recorded by ECM. - *: 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 canister pressure sensor. If the stabilized system pressure is higher than [second reference pressure x 0.2], the ECM interprets this as the purge VSV being stuck open. The ECM illuminates the MIL and stores the DTC (2 trip detection logic). Purge VSV stuck closed In operation D, the canister pressure sensor measures the EVAP (Evaporative Emission) system pressure. The pressure measurement for the purge VSV monitor begins when the purge VSV is turned on (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa(gauge) [2.25 mmHg(gauge)] 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, illuminates the MIL and sets the DTC (2 trip detection logic).
2. PURGE FLOW MONITOR The purge flow monitor consists of 2 monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary.

1. The 1st monitor While the engine is running and the purge VSV 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.
2. 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(gauge) [3 mmHg(gauge)], the ECM interprets this as the purge VSV being stuck closed, illuminates the MIL and stores DTC P0441 (2 trip detection logic).

Atmospheric pressure check

In order to ensure reliable malfunction detection, the variation between the atmospheric pressures, before and after conduction of the purge flow monitor, is measured by the ECM.

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

Scheme 139

1. DTC P0451: Canister pressure sensor abnormal voltage fluctuation or being constant If the canister pressure sensor voltage output fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as the canister pressure sensor voltage fluctuating, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the DTC. Alternatively, if the sensor voltage output does not change for 2 minutes, the ECM interprets this as the sensor being stuck, and stops the monitor. The ECM then illuminates the MIL and stores the DTC. (Both the malfunctions are detected by 2 trip detection logic.)
2. DTC P0452: Canister pressure sensor voltage low If the canister pressure sensor voltage output (pressure) is less than 0.45 V: 42.11009 kPa(abs) [315.86779 mmHg(abs)], the ECM interprets this as an open or short circuit in the canister pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the DTC (1 trip detection logic).
3. DTC P0453: Canister pressure sensor voltage high If the canister pressure sensor voltage output (pressure) is higher than 4.9 V: 123.76147 kPa(abs) [928.33479 mmHg(abs)], the ECM interprets this as an open or short circuit in the canister pressure sensor or its circuit, and stops the EVAP system monitor. The ECM then illuminates the MIL and stores the DTC (1 trip detection logic).

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

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

HINT

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

*: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.

Scheme 140

1. (a) P0455: EVAP (Evaporative Emission) gross leak In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than [second reference pressure x 0.2] (near atmospheric pressure), the ECM determines that the EVAP system has a large leak, illuminates the MIL and stores the DTC (2 trip detection logic).
2. (b) P0456: EVAP very small leak In operation C, the leak detection pump creates negative pressure (vacuum) in the EVAP system and the EVAP system pressure is measured. If the stabilized system pressure is higher than second reference pressure, the ECM determines that the EVAP system has a small leak, illuminates the MIL and stores the DTC (2 trip detection logic).

The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. The skid control ECU converts these wheel speed signals into a 4-pulse signal and outputs it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of these pulse signals.

Scheme 141

If there is no speed signal from the combination meter assembly even though the ECM determines that the vehicle is being driven, the ECM interprets this as a malfunction in the speed signal circuit. The ECM then illuminates the MIL and sets the DTC.

The stop light switch is a duplex system that transmits two signals: STP and ST1-. These two signals are used by the ECM to monitor whether or not the brake system is working properly. If the signals, which indicate the brake pedal is being depressed and released, are detected simultaneously, the ECM interprets this as a malfunction in the stop light switch and sets the DTC.

HINT

The normal signal conditions are as shown in the table below.

1. [OFF] denotes ground potential.
2. [ON] denotes battery potential (+B).
3. On the Techstream, both the Data List items Stop Light Switch and ST1 are ON when the brake pedal is depressed because the ST1 indication characteristic is opposite to the Stop Light Switch indication.

This DTC indicates that the stop light switch remains on. When the stop light switch remains on during "STOP and GO" driving, the ECM interprets this as a fault in the stop light switch and the MIL comes on and the ECM stores the DTC. The vehicle must STOP (less than 3 km/h (1.86 mph)) and GO (30 km/h (18.65 mph) or more) 5 times for two driving cycles in order to detect a malfunction.

The idle speed is controlled by the Electronic Throttle Control System (ETCS). The ETCS is comprised of: 1) one valve type throttle body; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects the opening angle of the throttle valve; 4) the accelerator pedal position sensor, which detects the accelerator pedal position; 5) the ECM, which controls the ETCS. Based on the target idle speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

The ECM monitors the idle speed and idling air flow volume to conduct Idle Speed Control (ISC). The ECM determines that the ISC system is malfunctioning if either of the following conditions is met

1. The difference between the target engine idle speed and actual engine idle speed exceeds the threshold and the IAC flow rate learned value is stuck at the upper or lower limit for 5 seconds or more.
2. After driving at a vehicle speed of 10 km/h (6.25 mph) or more, the difference between the target and actual engine idle speed exceeds the threshold 5 times or more during a driving cycle, and then the system determines that the IAC flow rate learned value is stuck at the upper or lower limit, or that the IAC flow rate learned value has been changed by an amount that exceeds the threshold.

Scheme 142

This monitor will run when the engine is started at an engine coolant temperature of -10 to 60°C (14 to 140°F). The DTC is stored after the engine idles for 13 seconds (2 trip detection logic).

The DTC is designed to monitor the idle air control at cold start. When the engine is started at an engine coolant temperature of below 60°C (140°F), the ECM measures the accumulated mass air flow during engine idling. If the accumulated mass air flow does not reach the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The electronic throttle control system controls the idle speed. The electronic throttle control system operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idle speed.

Note. When the cable is disconnected from the negative (-) battery terminal during inspections or repairs, the idle speed control learned values are cleared. This DTC cannot be stored with the idle speed control learned values cleared.

HINT

The idle speed control learning is performed when the engine is warmed up and has been idling for 5 minutes.

Scheme 143

This monitor will run when the engine is started at an engine coolant temperature of -10 to 60°C (14 to 140°F). The DTC is stored after the engine idles for 13 seconds (2 trip detection logic).

The DTC is designed to monitor the ignition timing at cold start. When the engine is started at an engine coolant temperature of below 60°C (140°F), the ECM checks the ignition timing during engine idling. If the ignition timing advances beyond the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

Note. When the cable is disconnected from the negative (-) battery terminal during inspections or repairs, the idle speed control learned values are cleared. This DTC cannot be stored with the idle speed control learned values cleared.

HINT

Idle speed control learning is performed when the engine is warmed up and has been idling for 5 minutes.

Scheme 144

The battery supplies electricity to the ECM even when the engine switch is off. This power allows the ECM to store data such as DTC history, freeze frame data and fuel trim values. If the battery voltage falls below a minimum level, these memories are cleared and the ECM determines that there is a malfunction in the power supply circuit. When the engine is next started, the ECM will illuminate the MIL and set the DTC.

HINT

If DTC P0560 is set, the ECM does not store other DTCs.

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM functioning properly. It is diagnosed by internal "mirroring" of the main CPU and sub CPU to detect the Random Access Memory (RAM) errors. If outputs from these CPUs are different and deviate from the standards, the ECM will illuminate the MIL and set a DTC immediately.

The ECM continuously monitors its main and sub CPUs. This self-check ensures that the ECM is functioning properly. If outputs from the CPUs are different and deviate from the standards, the ECM will illuminate the MIL and set the DTC immediately.

The ECM continuously monitors its internal processors (CPUs) and heated oxygen sensor transistors. This self-check ensures that the ECM functioning properly.

The main CPU and sub CPU of the ECM perform data communication between each other. The main CPU monitors the communications and WDC pulses from the sub CPU. When the malfunction below is detected, the DTC is stored.

The ECM monitors the input signals of the No. 1 accelerator pedal position sensor. When the input signals and control signals deviate, the DTC is stored.

The ECM monitors the signals of the No. 1 throttle position sensor and stop light switch assembly. As the ECM monitors the input signals of the No. 1 throttle position sensor and the STP signals of the stop light switch assembly, if the input signals and control signals deviate, the DTC is stored.

While the engine is being cranked, battery voltage is applied to terminal STA of the ECM.

If the ECM detects the Starter Control (STA) signal while the vehicle is being driven, it determines that there is a malfunction in the STA circuit. The ECM then illuminates the MIL and sets the DTC.

This monitor runs when the vehicle is driven at 20 km/h (12.43 mph) for over 20 seconds.

See also:
• ON-VEHICLE INSPECTION [08/2012 - ] - Step 1
• ON-VEHICLE INSPECTION [08/2012 - ] - Step 3
• ON-VEHICLE INSPECTION [08/2012 - ] - Step 9
• ON-VEHICLE INSPECTION [08/2012 - ]
• ON-VEHICLE INSPECTION [08/2012 - ] - Step 2
• REMOVAL [08/2012 - ]
• COMPONENTS [08/2012 - ]
• REMOVAL [08/2012 - ]