Engine Control System (2TR-FE) (Diagnostic Codes P043E-P1605): Overview Toyota 4Runner V

DESCRIPTION

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

MONITOR 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 609

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 driving cycles.

*: Typical value.

Scheme 610

The circuit description can be found in 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.

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1. Key-off Monitor 5 hours* after the ignition 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 below 35°C (95°F) 5 hours after the ignition switch is turned off, the monitor check starts 2 hours later. If it is still not below 35°C (95°F) 7 hours after the ignition switch is turned off, the monitor check starts 2.5 hours later. Sequence Operation Description Duration - ECM activation Activated by soak timer, 5 hours (7 or 9.5 hours) after ignition switch turned off. - A Atmospheric pressure measurement Vent valve turned OFF (vent) and EVAP system pressure measured by ECM in order to register atmospheric pressure. If pressure in EVAP system not between 70 kPa and 110 kPa (525 mmHg and 825 mmHg), ECM cancels EVAP system monitor. 60 seconds B First 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 they 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. 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. - HINT: *: 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 (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 (Evaporative Emission) system pressure. The pressure measurement for purge VSV monitor is begun when the purge VSV is turned ON (open) after the EVAP leak check. When the measured pressure indicates an increase of 0.3 kPa (2.25 mmHg) or more, the purge VSV is functioning normally. If the pressure does not increase, the ECM interprets this as the purge VSV being stuck closed. The ECM illuminates the MIL and 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 (Vacuum Switching Valve) is ON (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor.
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 0.5 kPa (3.75 mmHg), 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.

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

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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.

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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 vehicle speed sensor monitors the wheel rotation speed and sends a signal to the skid control ECU. The skid control ECU converts the wheel speed signal into a pulse signal and transmits it to the ECM via the combination meter assembly. The ECM determines the vehicle speed based on the frequency of this pulse signal.

HINT

Each ECU controls its respective system based on this pulse signal, and if a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems that use the vehicle speed signal to perform control will not operate normally.

Scheme 618

The ECM assumes that the vehicle is being driven when the indicated vehicle speed is higher than 9 km/h (5.59 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 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 619

The idling speed is controlled by the electronic throttle control system. The electronic throttle control system 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 electronic throttle control system. 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 or NSW is on 5 times or more during a driving cycle.

Scheme 620

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 idle air control at cold start. When the engine is started with the engine coolant temperature below 50°C (122°F), the ECM measures the accumulated mass air flow while the engine is idling. If it does not reach the threshold 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 (Electronic 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) learning 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 621

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 while the engine is 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 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 622

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 and 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, battery voltage is applied to terminal STA of the ECM.

If the ECM detects the starter signal (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.

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.

*: Name of Data List item

This DTC is stored when a deviation from pressure sensor characteristics is detected.

The pressure sensors* are checked 55 minutes after the ignition switch is turned off. If the pressures detected by the pressure sensors* differ by a certain amount, the MIL is illuminated and a DTC is stored (2 trip detection logic).

*: P106B checks the canister pressure sensor and the pressure sensor of the air switching valve.

HINT

Correct judgment may not be possible when the elevation is 4000 m (13120 ft.) or more.

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.