DESCRIPTION
Refer to DTC P0300. Refer to «DESCRIPTION».
Refer to DTC P2195, P2197. Refer to «DESCRIPTION».
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P219A P219B | The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic). | Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
MONITOR DESCRIPTION
Fuel System Air Fuel Ratio Cylinder Imbalance Monitor
The ECM uses the air fuel ratio sensor and crankshaft position sensor to monitor the difference in air fuel ratios between the cylinders caused by differences in injection volumes between the cylinders, leakage in the intake or exhaust system, etc.
When the air fuel ratios of the cylinders are lean or rich with respect to each other, the ECM determines that a problem is present and stores a DTC.
Air Fuel Ratio Sensor Monitoring Method
When the system detects a difference in air fuel ratios between the cylinders due to fluctuation in the air fuel ratio sensor output over 1 engine cycle (2 crankshaft revolutions), the system determines that there is a problem.
Crankshaft Position Sensor Monitoring Method
The system monitors the engine speed variation and when the variation becomes large, the system determines that there is a difference in air fuel ratios between the cylinders, which it determines to be a problem.
Refer to DTC P0300. Refer to «DESCRIPTION».
Refer to DTC P2195, P2197. Refer to «DESCRIPTION».
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P219A P219B | The difference in air fuel ratios between the cylinders exceeds the threshold (2 trip detection logic). | Fuel injector assembly Intake system Gas leaks from exhaust system Ignition system Compression pressure Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
Fuel System Air Fuel Ratio Cylinder Imbalance Monitor
The ECM uses the air fuel ratio sensor and crankshaft position sensor to monitor the difference in air fuel ratios between the cylinders caused by differences in injection volumes between the cylinders, leakage in the intake or exhaust system, etc.
When the air fuel ratios of the cylinders are lean or rich with respect to each other, the ECM determines that a problem is present and stores a DTC.
Air Fuel Ratio Sensor Monitoring Method
When the system detects a difference in air fuel ratios between the cylinders due to fluctuation in the air fuel ratio sensor output over 1 engine cycle (2 crankshaft revolutions), the system determines that there is a problem.
Crankshaft Position Sensor Monitoring Method
The system monitors the engine speed variation and when the variation becomes large, the system determines that there is a difference in air fuel ratios between the cylinders, which it determines to be a problem.
Refer to DTC P2195. Refer to «DESCRIPTION».
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2237 P2240 | Open in the circuit between terminals A1A+ (A2A-) and A1A- (A2A-) of the air fuel ratio sensor while engine running (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2238 P2241 | Case 1: Condition (a) or (b) continues for 5.0 seconds or more(2 trip detection logic):(a) Voltage at terminal A1A+ (A2A+) is 0.5 V or less(b) Voltage difference between terminals A1A+ (A2A+) and A1A- (A2A-) is 0.1 V or less Case 2: Air fuel ratio sensor admittance is less than 0.0074 1/ohms for 10 seconds or more(2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2239 P2242 | A1A+ (A2A+) voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2252 P2255 | A1A- (A2A-) voltage is 0.5 V or less for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2253 P2256 | A1A- (A2A-) voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
HINT
- DTCs P2237, P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.
- DTCs P2240, P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.
These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if the air fuel ratio sensor output drops. To detect these problems, the voltage of the air fuel ratio sensor is monitored when turning the engine switch on (IG), and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the air fuel ratio sensor is between 0.5 V and 4.5 V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM determines that there is a malfunction in the air fuel ratio sensor. If the same malfunction is detected in next driving cycle, the MIL is illuminated and a DTC is stored.
Refer to DTC P2195. Refer to «DESCRIPTION».
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2237 P2240 | Open in the circuit between terminals A1A+ (A2A-) and A1A- (A2A-) of the air fuel ratio sensor while engine running (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2238 P2241 | Case 1: Condition (a) or (b) continues for 5.0 seconds or more(2 trip detection logic):(a) Voltage at terminal A1A+ (A2A+) is 0.5 V or less(b) Voltage difference between terminals A1A+ (A2A+) and A1A- (A2A-) is 0.1 V or less Case 2: Air fuel ratio sensor admittance is less than 0.0074 1/ohms for 10 seconds or more(2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2239 P2242 | A1A+ (A2A+) voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2252 P2255 | A1A- (A2A-) voltage is 0.5 V or less for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
| P2253 P2256 | A1A- (A2A-) voltage is more than 4.5 V for 5.0 seconds or more (2 trip detection logic) | Open or short in air fuel ratio sensor (bank 1, 2 sensor 1) circuit Air fuel ratio sensor (bank 1, 2 sensor 1) ECM |
HINT
- DTCs P2237, P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 air fuel ratio sensor circuit.
- DTCs P2240, P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 air fuel ratio sensor circuit.
These DTCs are output when there is an open or short in the air fuel ratio sensor circuit, or if the air fuel ratio sensor output drops. To detect these problems, the voltage of the air fuel ratio sensor is monitored when turning the engine switch on (IG), and the admittance (admittance is an electrical term that indicates the ease of flow of current) is checked while driving. If the voltage of the air fuel ratio sensor is between 0.5 V and 4.5 V, it is considered normal. If the voltage is out of the specified range, or the admittance is less than the standard value, the ECM determines that there is a malfunction in the air fuel ratio sensor. If the same malfunction is detected in next driving cycle, the MIL is illuminated and a DTC is stored.
The description can be found in the EVAP (Evaporative Emission) System. Refer to «DESCRIPTION».
5 hours*1 after the engine switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.
HINT
*1: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the engine 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 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. | 360 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*2 |
| D | Purge VSV monitor | Purge VSV is opened and then EVAP system pressure is measured by ECM. Large increase indicates normal. | 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 is leaking. | 60 seconds |
| Final check | Atmospheric pressure is measured and then monitoring result is recorded by ECM. |
*2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
Scheme 42
P2420: Vent valve stuck open (vent)
In operation C, the vent valve turns ON (closed) and the EVAP system pressure is then measured by the ECM, using the canister pressure sensor, to conduct an EVAP leak check. If the pressure does not increase when the vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL and sets the DTC.
Scheme 43
The description can be found in the EVAP (Evaporative Emission) System. Refer to «DESCRIPTION».
5 hours*1 after the engine switch is turned off, the leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.
HINT
*1: If the engine coolant temperature is not below 35°C (95°F) 5 hours after the engine 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 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. | 360 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*2 |
| D | Purge VSV monitor | Purge VSV is opened and then EVAP system pressure is measured by ECM. Large increase indicates normal. | 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 is leaking. | 60 seconds |
| Final check | Atmospheric pressure is measured and then monitoring result is recorded by ECM. |
*2: If only a small amount of fuel is in the fuel tank, it takes longer for the EVAP pressure to stabilize.
P2420: Vent valve stuck open (vent)
In operation C, the vent valve turns ON (closed) and the EVAP system pressure is then measured by the ECM, using the canister pressure sensor, to conduct an EVAP leak check. If the pressure does not increase when the vent valve is open, the ECM interprets this as the vent valve being stuck open. The ECM illuminates the MIL and sets the DTC.
The soak timer operates after the engine switch is turned off. When the certain amount of time has elapsed after turning the engine switch off, the soak timer activates the ECM to perform malfunction checks which can only be performed after the engine is stopped. The soak timer is built into the ECM.
Scheme 44
- While the engine is running, the ECM monitors the synchronization of the soak timer and the CPU clock. If these two are not synchronized, the ECM interprets this as a malfunction, illuminates the MIL and stores the DTC.
- If the soak timer activates the ECM even though only a short amount of time has elapsed since the engine switch was turned off, or if the soak timer does not activate the ECM even though a considerable amount of time has elapsed since the engine switch was turned off, the ECM determines that the soak timer is malfunctioning, illuminates the MIL and stores a DTC the next time the engine switch is turned on (IG).
The Transmission Control Module (TCM) and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angle of the throttle valve, temperature of intake air, temperature of engine coolant, engine torque and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| U0101 | Following conditions are met for 1.25 seconds (1 trip detection logic): Engine switch on (IG) Battery voltage 10.5 V or more No communication between ECM and TCM | ECM to TCM circuit TCM ECM |
The Transmission Control Module (TCM) and ECM perform 2-way communication with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine speed, required engine torque, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine speed, opening angle of the throttle valve, temperature of intake air, temperature of engine coolant, engine torque and other data. If the TCM cannot communicate with the ECM, the TCM will conclude that there is a malfunction in the CAN system, illuminate the MIL and set a DTC.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| U0101 | Following conditions are met for 1.25 seconds (1 trip detection logic): Engine switch on (IG) Battery voltage 10.5 V or more No communication between ECM and TCM | ECM to TCM circuit TCM ECM |
LOCATION
Scheme 45
The active control engine mount system decreases engine vibration at a low engine speed using the vacuum switching valve for active control engine mount. The vacuum switching valve for active control engine mount is controlled by a pulse signal transmitted to the vacuum switching valve for active control engine mount from the ECM. The frequency of this pulse signal is matched to the engine speed to decrease engine vibration.
Scheme 46
LOCATION
Scheme 47
Scheme 48
The active control engine mount system decreases engine vibration at a low engine speed using the vacuum switching valve for active control engine mount. The vacuum switching valve for active control engine mount is controlled by a pulse signal transmitted to the vacuum switching valve for active control engine mount from the ECM. The frequency of this pulse signal is matched to the engine speed to decrease engine vibration.
When the vehicle is being driven with the accelerator pedal depressed, depressing the brake pedal without releasing the accelerator pedal will activate the brake override system to restrict driving torque. The conditions for activating the brake override system as well as the items that are controlled are explained below.
Scheme 49
Activation Conditions
- Vehicle is running at or above the specified speed.
- The accelerator pedal is depressed beyond a specified level, and then the brake pedal is depressed.
Note. The vehicle may not enter the brake override system control due to the relation of the accelerator pedal angle and the vehicle's speed.
Items Controlled
- Driving torque is restricted.
HINT
During brake override system control, the value for the accelerator pedal angle (which is used for engine control) is forcibly reduced to a specified value. For this reason, the Data List value for Accelerator Position will be replaced with a specified value regardless of the actual accelerator pedal angle (Accel Sens. No. 1 Volt %, Accel Sens. No. 2 Volt %)
Deactivation Conditions
- When the Stop Light Switch turns OFF or the actual accelerator pedal angle increases or decreases beyond the specified range.
When the vehicle is being driven with the accelerator pedal depressed, depressing the brake pedal without releasing the accelerator pedal will activate the brake override system to restrict driving torque. The conditions for activating the brake override system as well as the items that are controlled are explained below.
Activation Conditions
- Vehicle is running at or above the specified speed.
- The accelerator pedal is depressed beyond a specified level, and then the brake pedal is depressed.
Note. The vehicle may not enter the brake override system control due to the relation of the accelerator pedal angle and the vehicle's speed.
Items Controlled
- Driving torque is restricted.
HINT
During brake override system control, the value for the accelerator pedal angle (which is used for engine control) is forcibly reduced to a specified value. For this reason, the Data List value for Accelerator Position will be replaced with a specified value regardless of the actual accelerator pedal angle (Accel Sens. No. 1 Volt %, Accel Sens. No. 2 Volt %)
Deactivation Conditions
- When the Stop Light Switch turns OFF or the actual accelerator pedal angle increases or decreases beyond the specified range.
| *1 | Purge VSV | *2 | EVAP Hose (to Intake Air Surge Tank Assembly) |
|---|---|---|---|
| *3 | EVAP Hose (from Canister) | *4 | Canister Pump Module |
| *5 | Canister | *6 | Canister Filter |
| *7 | Air Inlet Port | *8 | Fuel Cap |
| *9 | Fuel Tank | ||
| *a | Location of EVAP (Evaporative Emission) System | *b | Purge Line |
TEXT IN ILLUSTRATION
HINT
The canister pressure sensor, the leak detection pump and the vent valve are built into the canister pump module.
| *1 | Intake Air Surge Tank Assembly | *2 | Purge VSV |
|---|---|---|---|
| *3 | Throttle Valve | *4 | Canister |
| *5 | Cut-off Valve | *6 | Fuel Tank |
| *7 | Air Cleaner | *8 | ECM |
| *9 | Canister Filter | *10 | Soak Timer |
| *11 | Canister Pump Module | *12 | Fuel Cap |
| *13 | Roll-Over Valve | ||
| *a | EVAP System Circuit |
TEXT IN ILLUSTRATION
Note. In the EVAP system of this vehicle, turning ON the vent valve does not seal off the EVAP system. To check for leaks in the EVAP system, disconnect the air inlet vent hose and apply pressure from atmospheric side of the canister.
While the engine is running, if a predetermined condition (closed-loop, etc.) is met, the purge VSV is opened by the ECM and fuel vapors stored in the canister are purged to the intake air surge tank assembly. The ECM changes the duty cycle ratio of the purge VSV to control purge flow volume.
The purge flow volume is also determined by the intake air surge tank assembly pressure. Atmospheric pressure is allowed into the canister through the vent valve to ensure that the purge flow is maintained when negative pressure (vacuum) is applied to the canister.
The following two monitors run to confirm appropriate EVAP system operation.
- Key-off monitor This monitor checks for EVAP (evaporative emission) system leaks and canister pump module malfunctions. The monitor starts 5 hours* after the engine switch is turned off. At least 5 hours are required for the fuel to cool down to stabilize the EVAP pressure, thus making the EVAP system monitor more accurate. The leak detection pump creates negative pressure (vacuum) in the EVAP system and the pressure is measured. Finally, the ECM monitors for leaks from the EVAP system, and malfunctions in both the canister pump module and purge VSV based on the EVAP pressure. HINT: *: If the engine coolant temperature is not below 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 below 35°C (95°F) 7 hours after the engine switch is turned off, the monitor check starts 2.5 hours later.
- Purge flow monitor The purge flow monitor consists of the 2 monitors. The 1st monitor is conducted every time and the 2nd monitor is activated if necessary. The 1st monitor While the engine is running and the purge VSV (Vacuum Switching Valve) is on (open), the ECM monitors the purge flow by measuring the EVAP pressure change. If negative pressure is not created, the ECM begins the 2nd monitor. The 2nd monitor The vent valve is turned ON (closed) and the EVAP pressure is then measured. If the variation in the pressure is less than 0.15 kPa(gauge) [1.125 mmHg(gauge)], 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 pressures, before and after of the purge flow monitor, is measured by the ECM. TEXT IN ILLUSTRATION *1 ECM *2 Soak Timer *3 Purge VSV (on) *4 Fuel Cap *5 Canister Filter *6 Fuel Tank *7 Leak Detection Pump (off) *8 Canister Pressure Sensor *9 Reference Orifice (0.02 inch) *10 Vent Valve (off) *11 Canister Pump Module *12 Canister *a EVAP Purge Flow *b to Intake Air Surge Tank Assembly Component Operation Canister Contains activated charcoal to absorb EVAP (Evaporative Emissions) generated in fuel tank. Cut-off valve Located in fuel tank. Valve floats and closes when fuel tank is 100% full. Purge VSV (Vacuum Switching Valve) Opens or closes line between canister and intake air surge tank assembly. ECM uses purge VSV to control EVAP purge flow. In order to discharge EVAP absorbed by canister to intake air surge tank assembly, ECM opens purge VSV. EVAP discharge volume to intake air surge tank assembly controlled by purge VSV duty cycle (current-carrying time). (Open: on, Close: off) Roll-over valve Located in fuel tank. Valve closes by its own weight when vehicle overturns to prevent fuel from spilling out. Soak timer Built into ECM. To ensure accurate EVAP monitor, measures 5 hours (+/-15 min) after engine switch is turned off. This allows fuel to cool down, stabilizing EVAP pressure. When approximately 5 hours elapsed, ECM activates (Scheme 42) Canister pump module Consists of (a) to (d) below. Canister pump module cannot be disassembled. (a) Vent valve Vents and closes EVAP system. When ECM turns valve on, EVAP system is closed. When ECM turns valve off, EVAP system is vented. Negative pressure (vacuum) is created in EVAP system to check for EVAP leaks by closing purge VSV, turning on vent valve (closing it) and operating leak detection pump see scheme 1 (b) Canister pressure sensor Indicates pressure as voltages. ECM supplies regulated 5 V to pressure sensor, and uses feedback from sensor to monitor EVAP system pressure see scheme 2 (c) Leak detection pump Creates negative pressure (vacuum) in EVAP system for leak check. (d) Reference orifice Has opening with 0.02 inch diameter. Vacuum is produced through orifice by closing purge VSV, turning off vent valve and operating leak detection pump, to monitor reference pressure. Reference pressure is used when checking for small EVAP leaks. TEXT IN ILLUSTRATION *1 Vent Valve: off (vent) *2 Canister *3 Reference Orifice (0.02 Inch) *4 Canister Pressure Sensor *5 Leak Detection Pump: off *6 Vent Valve: on (closed) *7 Leak Detection Pump: on - - *a Canister Pump Module see scheme 1 *b Airflow *c Condition: Purge Flow *d Condition: Leak Check *e to Canister Filter (Atmosphere)
When the engine switch is turned on (IG), the battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contact of the EFI MAIN relay and supplying power to terminals +B and +B2 of the ECM.
Scheme 50
When the engine switch is turned on (IG), the battery voltage is applied to IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contact of the EFI MAIN relay and supplying power to terminals +B and +B2 of the ECM.
The ECM constantly uses 5 V from the battery voltages supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.
Scheme 51
When the VC circuit is shorted, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.
HINT
Under normal conditions, the MIL is illuminated when the engine switch is turned on (IG). The MIL goes off when the engine is started.
Scheme 52
Scheme 53
The ECM constantly uses 5 V from the battery voltages supplied to the +B (BATT) terminal to operate the microprocessor. The ECM also provides this power to the sensors through the VC output circuit.
When the VC circuit is shorted, the microprocessor in the ECM and sensors that are supplied power through the VC circuit are inactivated because the power is not supplied from the VC circuit. Under this condition, the system does not start up and the MIL does not illuminate even if the system malfunctions.
HINT
Under normal conditions, the MIL is illuminated when the engine switch is turned on (IG). The MIL goes off when the engine is started.
Refer to DTC P0230. Refer to «DESCRIPTION».
Scheme 54
Refer to DTC P0230. Refer to «DESCRIPTION».
The fuel injector assemblies are located on the intake air surge tank assembly. They inject fuel into the cylinders based on signals from the ECM.
Scheme 55
The fuel injector assemblies are located on the intake air surge tank assembly. They inject fuel into the cylinders based on signals from the ECM.
While the engine is being cranked, current flows from terminal STAR of the power management control ECU to the park/neutral position switch and also flows to terminal STA of the ECM (STA signal).
Scheme 56
While the engine is being cranked, current flows from terminal STAR of the power management control ECU to the park/neutral position switch and also flows to terminal STA of the ECM (STA signal).
This circuit opens and closes the intake air control valve assembly in response to changes in the engine load in order to increase the intake efficiency using the acoustic control induction system.
When the engine speed is between 0 and 4300 RPM and the throttle valve opening angle is 60° or more, the ECM supplies current to the actuator (on status), to close the intake air control valve assembly. Under other conditions, the intake air control valve assembly is open.
Scheme 57
Scheme 58
This circuit opens and closes the intake air control valve assembly in response to changes in the engine load in order to increase the intake efficiency using the acoustic control induction system.
When the engine speed is between 0 and 4300 RPM and the throttle valve opening angle is 60° or more, the ECM supplies current to the actuator (on status), to close the intake air control valve assembly. Under other conditions, the intake air control valve assembly is open.
The air cleaner is equipped with 2 inlets, one of which is opened or closed by the air intake control valve. This system reduces intake noise and increases engine power at low-to-high engine speed ranges.
When the engine is operating in the low-to-mid speed range, this control operates the air intake control valve to close one of the air cleaner inlets. When the engine speed is more than 3600 RPM and the opening angle of the throttle valve is more than 60°, the ECM activates the VSV and opens the air intake control valve.
Scheme 59
Scheme 60
The air cleaner is equipped with 2 inlets, one of which is opened or closed by the air intake control valve. This system reduces intake noise and increases engine power at low-to-high engine speed ranges.
When the engine is operating in the low-to-mid speed range, this control operates the air intake control valve to close one of the air cleaner inlets. When the engine speed is more than 3600 RPM and the opening angle of the throttle valve is more than 60°, the ECM activates the VSV and opens the air intake control valve.
The Malfunction Indicator Lamp (MIL) is used to indicate vehicle malfunctions detected by the ECM. By turning the engine switch on (IG), power is supplied to the MIL circuit, and the ECM provides the circuit ground which illuminates the MIL.
The MIL operation can be checked visually. When the engine switch is turned on (IG), the MIL should be illuminated and should turn off after engine is started. If the MIL remains illuminated or does not illuminate, conduct the following troubleshooting procedure. If the ECM detects any trouble, the MIL illuminates. At this time, the ECM records a DTC in the memory.
