Engine Control System (1GR-FE) (Diagnostic Codes (P0335-P1605): Overview Toyota 4Runner V

DESCRIPTION

The crankshaft position sensor system consists of a crankshaft position sensor plate and 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 277

1. Reference: Inspection using an oscilloscope (VV1, VV2 and NE Signal Waveforms). HINT: The correct waveforms are as shown. VV1+ and VV2+ are the VVT sensor signals, and NE+ is the crankshaft position sensor signal. Grounding failure of the shielded wire may cause noise in the waveforms. Item Content Terminal VV1+ - VV1- VV2+ - VV2- NE+ - NE- Equipment Setting 5 V/DIV., 20 msec./DIV. Condition Cranking or idling

MONITOR DESCRIPTION

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's Variable Valve Timing (VVT) sensor (VV1, VV2 signal) consists of a magnet and MRE (Magnetoresistive Element).

The camshaft timing 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 the camshaft angle data to the ECM.

The crankshaft position sensor plate has 34 teeth. The pickup coil generates 34 signals for each crankshaft revolution. Based on a combination of the VVT 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.

Scheme 278

1. Reference: Inspection using an oscilloscope HINT: The correct waveforms are as shown. VV1+ and VV2+ are the VVT sensor signals, and NE+ is the crankshaft position sensor signal. Item Content Terminal NE+ - NE- VV1+ - VV1- VV2+ - VV2- Equipment Setting 5 V/DIV. 20 msec./DIV. Condition Cranking or idling

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

HINT

1. These DTCs indicate malfunctions relating to the primary circuit.
2. If DTC P0351 is output, check the No. 1 ignition coil circuit.
3. If DTC P0352 is output, check the No. 2 ignition coil circuit.
4. If DTC P0353 is output, check the No. 3 ignition coil circuit.
5. If DTC P0354 is output, check the No. 4 ignition coil circuit.
6. If DTC P0355 is output, check the No. 5 ignition coil circuit.
7. If DTC P0356 is output, 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 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 279

Scheme 280

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 and E1 of the ECM connector. Item Content Terminal CH1: IGT1, IGT2, IGT3, IGT4, IGT5, IGT6 - E1 CH2: IGF1 - E1 Equipment Setting 2 V/DIV. 20 msec./DIV. Condition Cranking or idling

Scheme 281

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's Variable Valve Timing (VVT) sensor (EV1, EV2 signal) consists of a magnet and MRE (Magnetoresistive 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 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 the camshaft angle data to the ECM.

Scheme 282

1. Reference: Inspection using an oscilloscope HINT: The correct waveforms are as shown. EV1+ and EV2+ are the VVT sensor signal, and NE+ is the crankshaft position sensor signal. Item Content Terminal NE+ - NE- EV1+ - EV1- EV2+ - EV2- Equipment Setting 5 V/DIV. 20 msec./DIV. Condition Cranking or idling

If no signal is transmitted by the VVT sensor despite the camshaft 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 front catalyst 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 (OSC) 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 OSC 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 rich-lean cycle of the heated oxygen sensor is long, the OSC becomes greater. There is a direct correlation between the OSCs of the heated oxygen sensor and three-way catalytic converter.

The ECM uses the OSC value to determine the state of the three-way catalytic converter. If any deterioration has occurred, it illuminates the MIL and stores the 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 283

TEXT IN ILLUSTRATION

Refer to EVAP (Evaporative Emission) System, refer to DESCRIPTION .

5 hours* after the ignition 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 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.

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

Scheme 284

The leak detection pump creates negative pressure through the reference orifice. When the system is normal, the EVAP pressure is between 724 and 752 mmHg* and is saturated within a minute. If not, the ECM interprets this as a malfunction. The ECM will illuminate the MIL and store a DTC if this malfunction is detected in consecutive drive cycles.

*: Typical value.

Scheme 285

Refer to 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 286

Scheme 287

Scheme 288

1. Key-off Monitor 5 hours* after the ignition 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 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, 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 76 kPa-a and 110 kPa-a (570 mmHg-a and 825 mmHg-a), 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. 360 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 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 measured by ECM. Large increase indicates normality. 10 seconds E Second reference pressure measurement After second reference pressure measurement, leak check performed by comparing first and second reference pressure measurements. If stabilized system pressure higher than second reference pressure, ECM determines that EVAP system leaking. 60 seconds - Final check Atmospheric pressure measured, and then monitoring result 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 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 (Vacuum Switching Valve) 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 system pressure. The pressure measurement for the 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-g (2.25 mmHg-g) 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 stores 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 0.15 kPa-g (1.12 mmHg-g), the ECM interprets this as the purge VSV being stuck closed, and 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 pressure, before and after conduction of the purge flow monitor, is measured by the ECM.

HINT

DTC P0443 is applicable to Mexico models only.

To reduce hydrocarbon emissions, evaporated fuel from the fuel tank is routed through a charcoal canister to the intake manifold for combustion in the cylinders.

The ECM changes the duty signals to the Purge VSV (Vacuum Switching Valve for purge control) so that the intake amount of evaporated fuel is appropriate for the driving conditions (engine load, engine speed, vehicle speed, etc.) after the engine is warmed up.

Scheme 289

Refer to EVAP (Evaporative Emission) System, refer to DESCRIPTION .

Scheme 290

1. DTC P0451: Canister pressure sensor signal has noise or is fixed/flat If the canister pressure sensor voltage output fluctuates rapidly for 10 seconds, the ECM stops the EVAP system monitor. The ECM interprets this as noise from the canister pressure sensor 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 10 seconds, the ECM interprets this as the sensor signal being fixed/flat and stops the monitor. The ECM then illuminates the MIL and stores the DTC. (Both malfunctions are detected by 2 trip detection logic.)
2. DTC P0452: Canister pressure sensor voltage is low If the canister pressure sensor output [pressure] is below 42.1 kPa-a (315.9 mmHg-a), the ECM interprets this as an open or short circuit malfunction 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 is high If the canister pressure sensor output [pressure] is 123.8 kPa-a (928.4 mmHg-a) or higher, the ECM interprets this as an open or short circuit malfunction 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).

Refer to EVAP (Evaporative Emission) System, refer to DESCRIPTION .

5 hours* after the ignition 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 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.

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

Scheme 291

1. (a) P0455: EVAP 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 the 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 pulse signal and outputs it to the ECM via the combination meter assembly. The ECM determines the vehicle speed based on the frequency of this pulse signal.

Scheme 292

The ECM assumes that the vehicle is being driven when the indicated vehicle speed is higher than 9 km/h (5.6 mph). If there is no speed signal from the combination meter assembly despite this condition being met, the ECM interprets this as a malfunction in the speed signal circuit. The ECM then illuminates the MIL and stores 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 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 stores the DTC.

HINT

The normal switch 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.

Scheme 293

The idling speed is controlled by the ETCS (Electronic Throttle Control System). The ETCS is comprised of: 1) a 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; and 5) the ECM, which controls the ETCS. Based on the target idling speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

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

1. The difference between the target engine idling speed and actual engine idling 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 actual engine idling speed minus the target idling speed is less than -100 RPM or 150 RPM or more when the A/C and NSW are off, or less than -100 RPM or 200 RPM or more when the A/C and NSW are on 5 times or more during a driving cycle.

Scheme 294

The Electronic Throttle Control System (ETCS) controls the engine idling speed. The ETCS operates the throttle actuator to open and close the throttle valve, and adjusts the intake air amount to achieve the target idling speed.

In addition, the ECM retards the ignition timing and the ETCS increases the intake air amount to quickly increase the catalyst temperature at cold start to reduce emissions.

Scheme 295

The ECM monitors the intake air amount during idling, and the ignition timing.

When the engine coolant temperature is between -10°C and 50°C (14°F and 122°F), the ECM calculates the idling intake air amount for 10 seconds, beginning 3 seconds after the engine starts.

When the accumulated amount is below the threshold, the ECM interprets this as a malfunction in the Idle Speed Control (ISC) system at cold start.

The ECM also monitors the ignition timing at cold start and determines it to be incorrect when it is advanced to the same value as a warm engine for 5 seconds or more of the 10 second monitoring period.

Example

P050A is detected when all conditions below are met (2 trip detection logic).

1. The engine coolant temperature is between -10°C and 50°C (14°F and 122°F) when the engine starts.
2. The engine idles for 13 seconds after engine start.
3. The accumulated intake air amount is below the threshold.

The ECM stores the DTC and illuminates the MIL 13 seconds after the engine is next started.

Note. When the cable is disconnected from the negative battery terminal during inspection or repairs, the ISC learned values are cleared. ISC learning must be performed by warming up the engine and idling for 5 minutes with the engine coolant temperature at 75°C (167°F) or higher because DTCs cannot be detected with the ISC learned values cleared.

This monitor will run when the engine is started with the engine coolant temperature at -10 to 50°C (14 to 122°F). The DTC can be 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 with the engine coolant temperature below 50°C (122°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).

The ETCS (Electrical Throttle Control System) controls the idle speed. The ETCS 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 ISC (Idle Speed Control) learned values are cleared. This DTC cannot be stored with the ISC learned values cleared.

HINT

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

Scheme 296

The power steering oil pressure switch is turned on when a power steering wheel load is generated by turning the steering wheel. The ECM regulates the engine idling speed according to the voltage output of the sensor.

Scheme 297

The ECM monitors the power steering oil pressure switch voltage and uses this value to regulate the engine idling speed. When the power steering oil pressure switch output voltage deviates from the normal operating range, the ECM determines that there is a malfunction in the power steering oil pressure switch and stores a DTC.

The battery supplies electricity to the ECM even when the ignition 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, the memory is cleared and the ECM determines that there is a malfunction in the power supply circuit. When the engine is next started, the ECM illuminates the MIL and stores the DTC.

HINT

If DTC P0560 is stored, the ECM does not store other DTCs or the data stored in the ECM is partly cleared.

The ECM continuously monitors its own internal memory status, internal circuits, and output signals transmitted to the throttle actuator. This self-check ensures that the ECM is functioning properly. If any malfunction is detected, the ECM stores the appropriate DTC and illuminates the MIL.

The ECM memory status is diagnosed by internal mirroring of the main CPU and sub CPU to detect Random Access Memory (RAM) errors. The two CPUs also perform continuous mutual monitoring. The ECM illuminates the MIL and stores a DTC if: 1) outputs from the 2 CPUs are different or deviate from the standard, 2) the signals sent to the throttle actuator deviate from the standard, 3) a malfunction is found in the throttle actuator supply voltage, or 4) any other ECM malfunction is found.

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 standard, the ECM will illuminate the MIL and store a DTC immediately.

The ECM continuously monitors its internal processors (CPUs) and heated oxygen sensor transistors. This self-check ensures that the ECM is functioning properly. Malfunctions are diagnosed by internal "mirroring" of the main and sub CPUs to detect processor errors. If outputs from the processors deviate from the standard, the ECM will illuminate the MIL and store a DTC immediately.

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 signal malfunctions below are detected, this DTC is stored.

This DTC is stored when a communication error occurs in the ECM.

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

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

While the engine is being cranked, the positive 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 stores the DTC.

This monitor runs when the vehicle is driven at 20 km/h (12.4 mph) for over 20 seconds.

The ECM monitors its internal operation and stores this DTC when it detects an internal malfunction.

The ECM monitors its internal operation. If there is an internal operation malfunction, the ECM illuminates the MIL and stores a DTC.

DTC P0630 is stored when the Vehicle Identification Number (VIN) is not stored in the ECM, or the input VIN is incorrect. The VIN is input with the Techstream.

The ECM monitors the output voltage to the throttle actuator. This self-check ensures that the ECM is functioning properly. The output voltage is usually 0 V when the ignition switch is turned off. If the output voltage is 7 V or higher when the ignition switch is turned off, the ECM will illuminate the MIL and store this DTC when the ignition switch is turned to ON.

The stop light switch assembly is part of a duplex system that transmits 2 signals: STP and ST1-. These 2 signals are used by the ECM to monitor whether or not the brake system is working properly.

This DTC indicates that the stop light switch remains on. When the stop light switch remains on during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC.

This DTC indicates that the stop light switch remains on. When the stop light switch remains on during GO and STOP driving, the ECM interprets this as a fault in the stop light switch. Then the MIL illuminates and the ECM stores the DTC. The vehicle must GO (30 km/h (18.65 mph) or more) and STOP (less than 3 km/h (1.86 mph) 5 times for 2 driving cycles in order for the DTC to be stored.

This vehicle is equipped with a voltage inverter, which supplies power to various electrical appliances. When the main switch of the voltage inverter is turned on, the inverter relay turns on, and the inverter then converts the 12 V Direct Current (DC) of the battery into a 115 V Alternating Current (AC). The voltage inverter can output a maximum of 400 W from an outlet.

When the 115 V AC is output, a load is applied to the engine. The ECM controls the engine idling speed according to the vehicle speed and engine load. A speed signal is input to the inverter and an idle-up signal is transmitted to the ECM.

Scheme 298

While the engine is idling, the ECM performs idle up according to the power supply of the inverter to stabilize the engine idling speed.

When the vehicle is stationary and the inverter input exceeds 8.3 A, the inverter sends an idle-up signal from the OUT terminal of the inverter to the ELS2 terminal of the ECM.

If the idle-up signal is input into the ECM for 10 seconds while the vehicle is being driven, the ECM interprets this as a malfunction in the inverter circuit and stores the DTC.

Scheme 299

P1603

After starting the engine, this DTC is stored when the engine stops without the ignition switch being operated.

Using the Techstream, the conditions present when the DTC was stored can be confirmed by referring to the freeze frame data. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.

It is necessary to check if the vehicle has ran out of fuel before performing troubleshooting, as this DTC is also stored when the engine stalls due to running out of fuel.

P1605

This DTC is stored if the engine speed drops below the set speed.

Using the Techstream, the conditions present when the DTC was stored can be confirmed by referring to the freeze frame data. Freeze frame data records engine conditions when a malfunction occurs. This information can be useful when troubleshooting.

It is necessary to check if the vehicle ran out of fuel before performing troubleshooting, as this DTC is also stored when idling is unstable due to running out of fuel.