Engine Control (Sfi) (Diagnostic Codes (P0455-P2A00) & Circuit Tests): Overview Lexus LX J200

DESCRIPTION

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

MONITOR 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 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.

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

Scheme 103

Scheme 104

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 leakage, 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 leakage, 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 105

The ECM assumes that the vehicle is being driven when the indicated vehicle speed is more than 9 km/h (5.6 mph). If there is no speed signal from the combination meter despite these conditions 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 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 stores the DTC.

HINT

The normal conditions are as shown in the table below. The signals can be read using the Techstream.

Scheme 106

The idling speed is controlled by the ETCS (Electronic Throttle Control System). The ETCS is comprised of: 1) the one valve type throttle body; 2) the throttle actuator, which operates the throttle valve; 3) the Throttle Position (TP) sensor, which detects the opening angle of the throttle valve; 4) the Accelerator Pedal Position (APP) 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 apply

1. The learned idling air flow volume remains at the maximum or minimum volume for 5 seconds during a drive cycle.
2. After driving at 10 km/h (6.25 mph) or more, the actual engine idling speed varies from the target idling speed by between 100 rpm and 150 rpm, 5 times or more during a drive cycle.

Example

If the actual idling speed varies from the target idling speed by more than 150 rpm* 5 times during a drive cycle, the ECM illuminates the MIL and stores the DTC.

HINT

*: Threshold idling speed varies with engine load.

Scheme 107

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 will 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 at below 50°C (122°F), the ECM (PCM) measures the accumulated mass air flow at engine idling. If it does not reach the criteria within 10 seconds, the ECM (PCM) 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 learning values cleared. The ISC learning is performed when the engine is warmed up and has been idling for 5 minutes.

Scheme 108

This monitor will run when the engine is started at an engine coolant temperature of -10 to 50°C (14 to 122°F). The DTC will 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 at an engine coolant temperature of below 50°C (122°F), the ECM checks the ignition timing at 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 ISC (Idle Speed Control) learning values are cleared. This DTC cannot be stored with the ISC learning values cleared.

HINT

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

Scheme 109

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

Scheme 110

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

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

The ECM continuously monitors its internal processors (CPUs) and heated oxygen sensor (HO2S) transistors. This self-check ensures that the ECM is 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 signal malfunctions below are detected, a 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 (APP) sensor No. 1. When the input signals and control signals are deviated, a DTC is stored.

The ECM monitors the input signals of the Throttle Position (TP) sensor No. 1 and stop light switch. As the ECM monitors the input signals of the TP sensor No. 1 and the STP signals of the stop light switch, if the input signals and control signals are deviated, a 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.

DTC P0630 is stored when the Vehicle Identification Number (VIN) is not stored in the Engine Control Module (ECM) or the input VIN is incorrect. Input the VIN 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 usually is 0 V when the engine switch is turned off. If the output voltage is higher than 7 V when the engine switch is turned off, the ECM will illuminate the MIL and store DTC(s) when the engine switch is turned on (IG).

The camshaft position sensor (G signal) consists of a magnet and MRE (Magnetic Resistance Element).

The camshaft drive gear (LH) has 3 teeth on its inner circumference. When the camshaft gear rotates, air gap changes between the protrusion on the teeth and the MRE. The change affects the magnetic field and results in changes in the resistance of the MRE.

The crankshaft position sensor plate has 34 teeth and is installed to the rear end of the crankshaft. The crankshaft position sensor generates 34 signals with every crankshaft revolution. The ECM detects the standard crankshaft angle based on the G signal, and the actual crankshaft angle and engine speed by the NE signal.

The camshaft position sensor (G signal) consists of a magnet and MRE.

The camshaft drive gear has 3 teeth on its inner circumference. When the camshaft gear rotates, air gap changes between the protrusion on the gear and the MRE. The change affects the magnetic field and results in changes in the resistance of the MRE. The crankshaft position sensor plate has 34 teeth and outputs 34 signals with every crankshaft revolution. The ECM detects the standard crankshaft angle based on the G signal, and the actual crankshaft angle and engine speed by the NE signal.

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 DTC(s) immediately.

Refer to DTC P0412. Refer to «DESCRIPTION».

For a short time after a cold engine start, the ECM transmits command signals to the Air Injection Control Driver (AID) to drive the air pump and the Air Switching Valve (ASV). The AID detects open and short circuits according to the voltages at the AID terminals to the air pump and ASV, and the circuit voltage of the AID power source, and transmits diagnostic information as a signal to the ECM.

If the Secondary Air Injection (AIR) system circuit or the AID itself malfunctions, the AID sends a malfunction signal (duty signal) as diagnostic information to the ECM (when the system is normal, a system normal signal is sent). The ECM stores the DTC based on the diagnostic information from the AID.

EXAMPLE

1. The duty ratio of the diagnostic signal from the AID is 0 or 100% (remains at 0 V or the same as battery voltage).
2. The duty ratio of the diagnostic signal from the AID shows an impossible ratio (other than 0, 20, 40, 80 and 100%).
3. The AID outputs the normal signal (normal duty signal: 80%) while the system is not operating.

The throttle actuator is operated by the ECM and opens and closes the throttle valve using gears.

The opening angle of the throttle valve is detected by the Throttle Position (TP) sensor, which is mounted on the throttle body. The TP sensor provides feedback to the ECM. This feedback allows the ECM to appropriately control the throttle actuator and monitor the throttle opening angle as the ECM responds to driver inputs.

HINT

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

The ECM monitors the electrical current through the electronic actuator, and detects malfunctions and open circuits in the throttle actuator based on this value. If the current is outside the standard range, the ECM determines that there is a malfunction in the throttle actuator. In addition, if the throttle valve does not function properly (for example, stuck on), the ECM determines that there is a malfunction. The ECM then illuminates the MIL and stores DTC(s).

Example

When the electrical current is below 0.5 A and the throttle actuator duty ratio exceeds 80%, the ECM interprets this as the current being outside the standard range, illuminates the MIL and stores DTC(s).

If the malfunction is not repaired successfully, a DTC is stored when the engine is quickly revved to a high rpm several times after the engine is started and has idled for 5 seconds.

The throttle actuator is operated by the ECM, and opens and closes the throttle valve using gears. The opening angle of the throttle valve is detected by the Throttle Position (TP) sensor, which is mounted on the throttle body. The TP sensor provides feedback to the ECM so that it can control the throttle actuator (throttle valve) appropriately in response to driver inputs.

HINT

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

The ECM determines that there is a malfunction in the ETCS when the throttle valve remains at a fixed angle despite a high drive current from the ECM. The ECM illuminates the MIL and stores DTC(s).

If the malfunction is not repaired successfully, a DTC is stored when the accelerator pedal is fully depressed and released quickly (to fully open and close the throttle valve) after the engine is next started.

The ETCS (Electronic Throttle Control System) has a dedicated power supply circuit. The voltage (+BM) is monitored and when it is low (below 4 V), the ECM determines that there is a malfunction in the ETCS and cuts off the current to the throttle actuator.

When the voltage becomes unstable, the ETCS itself becomes unstable. For this reason, when the voltage is low, the current to the throttle actuator is cut. If repairs are made and the system returns to normal, turn the engine switch off. The ECM then allows the current to flow to the throttle actuator so that it can be restarted.

HINT

The ETCS does not use a throttle cable.

Scheme 111

The ECM monitors the battery supply voltage applied to the throttle actuator.

When the power supply voltage (+BM) drops below 4 V for 0.8 seconds or more, the ECM interprets this as an open in the power supply circuit (+BM). The ECM illuminates the MIL and stores the DTC.

If the malfunction is not repaired successfully, the DTC is stored 5 seconds after the engine is next started.

The Electronic Throttle Control System (ETCS) is composed of the throttle actuator, Throttle Position (TP) sensor, Accelerator Pedal Position (APP) sensor, and ECM. The ECM operates the throttle actuator to regulate the throttle valve in response to driver inputs. The TP sensor detects the opening angle of the throttle valve, and provides the ECM with feedback so that the throttle valve can be appropriately controlled by the ECM.

The ECM determines the actual opening angle of the throttle valve from the TP sensor signal. The actual opening angle is compared to the target opening angle commanded by the ECM. If the difference between these two values is outside the standard range, the ECM interprets this as a malfunction in the ETCS. The ECM then illuminates the MIL and stores the DTC.

If the malfunction is not repaired successfully, the DTC is stored when the accelerator pedal is quickly released (to close the throttle valve) after the engine speed reaches 5000 rpm by the accelerator pedal being fully depressed (fully open the throttle valve).

HINT

This ETCS (Electronic Throttle Control System) does not use a throttle cable.

The APP sensor is mounted on the accelerator pedal bracket and has 2 sensor circuits: VPA (main) and VPA2 (sub). This sensor is a non-contact type and uses Hall-effect elements in order to yield accurate signals even in extreme driving conditions, such as at high speeds as well as very low speeds. The voltage, which is applied to terminals VPA and VPA2 of the ECM, varies between 0.5 V and 4.5 V in proportion to the operating angle of the accelerator pedal (throttle valve). A signal from VPA indicates the actual accelerator pedal opening angle (throttle valve opening angle) and is used for engine control. A signal from VPA2 conveys the status of the VPA circuit and is used to check the APP sensor itself.

The ECM monitors the actual accelerator pedal opening angle (throttle valve opening angle) through the signals from VPA and VPA2, and controls the throttle actuator according to these signals.

Scheme 112

HINT

When any of these DTCs is output, check the APP sensor voltage by entering the following menus: Powertrain / Engine and ECT / Data List / ETCS / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

HINT

1. Accelerator pedal positions are expressed as voltages.

1. AP stands for Accelerator Pedal.

When either output voltage of VPA or VPA2 deviates from the standard range, or the difference between the output voltages of the 2 sensor circuits is less than the threshold, the ECM determines that there is a malfunction in the APP sensor. The ECM then illuminates the MIL and stores DTC(s).

Example

When the output voltage of VPA drops below 0.4 V for more than 0.5 seconds when the accelerator pedal is fully depressed, DTC P2122 is stored.

If the malfunction is not repaired successfully, a DTC is stored 2 seconds after the engine is next started.

HINT

Refer to DTC P2120. Refer to «DESCRIPTION».

When the difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that the Accelerator Pedal Position (APP) sensor is malfunctioning. The ECM turns on the MIL and the DTC is stored.

The A/F sensor generates a voltage* that corresponds to the actual air-fuel ratio. This sensor voltage is used to provide the ECM with feedback so that it can control the air-fuel ratio. The ECM determines the deviation from the stoichiometric air-fuel ratio level, and regulates the fuel injection time. If the A/F sensor malfunctions, the ECM is unable to control the air-fuel ratio accurately.

The A/F sensor is the planar type and is integrated with the heater, which heats the solid electrolyte (zirconia element). This heater is controlled by the ECM. When the intake air volume is low (the exhaust gas temperature is low), a current flows into the heater to heat the sensor in order to facilitate accurate air-fuel ratio detection. In addition, the sensor and heater portions are the narrow type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

In order to obtain a high purification rate of the carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx) components in the exhaust gas, a TWC is used. For the most efficient use of the TWC, the air-fuel ratio must be precisely controlled so that it is always close to the stoichiometric level.

*: Value changes inside the ECM. Since the A/F sensor is the current output element, a current is converted into a voltage inside the ECM. Any measurements taken at the A/F sensor or ECM connectors will show a constant voltage.

Scheme 113

HINT

1. DTCs P2195 and P2196 indicate malfunctions related to bank 1 A/F sensor circuit.
2. DTCs P2197 and P2198 indicate malfunctions related to bank 2 A/F sensor circuit.
3. Bank 1 refers to the bank that includes the No. 1 cylinder.
4. Bank 2 refers to the bank that includes the No. 2 cylinder.
5. When either of these DTCs is stored, check the A/F sensor output voltage by entering the following menus: Powertrain / Engine and ECT / Data List / A/F Control System / AFS Voltage B1S1 or AFS Voltage B2S1.
6. Short-term fuel trim values can also be read using the Techstream.
7. The ECM regulates the voltages at the A1A+ and A1A- or A2A+ and A2A- terminals of the ECM to a constant level. Therefore, the A/F sensor output voltage cannot be confirmed without using the Techstream.
8. If the A/F sensor is malfunctioning, the ECM stores DTC P2195, P2196, P2197 or P2198.

Sensor voltage detection monitor

Under the air-fuel ratio feedback control, if the A/F sensor output voltage indicates rich or lean for a certain period of time, the ECM determines that there is a malfunction in the A/F sensor. The ECM illuminates the MIL and stores DTC(s).

Example

If the A/F sensor output voltage is below 2.8 V (very rich condition) for 5 seconds, despite the rear HO2 sensor output voltage being below 0.59 V, the ECM stores DTC P2196 or P2198. Alternatively, if the A/F sensor output voltage is higher than 3.8 V (very lean condition) for 5 seconds despite the rear HO2 sensor output voltage being 0.21 V or higher, DTC P2195 or P2197 is stored.

Sensor current detection monitor

A rich air-fuel mixture causes a low A/F sensor current, and a lean air-fuel mixture causes a high A/F sensor current. Therefore, the sensor output becomes low during acceleration, and it becomes high during deceleration with the throttle valve fully closed. The ECM monitors the A/F sensor current during fuel cut and detects any abnormal current values.

If the A/F sensor output is 3.6 mA or higher for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the A/F sensor and stores DTC P2195 or P2197 (high-side stuck). If the A/F sensor output is below 1.4 mA for more than 3 seconds of cumulative time, the ECM stores DTC P2196 or P2198 (low-side stuck).

Scheme 114

Refer to DTC P2195. Refer to «DESCRIPTION».

HINT

1. DTCs P2237, P2238, P2239, P2252 and P2253 indicate malfunctions related to the bank 1 A/F sensor circuit.
2. DTCs P2240, P2241, P2242, P2255 and P2256 indicate malfunctions related to the bank 2 A/F sensor circuit.
3. Bank 1 refers to the bank that includes the No. 1 cylinder.
4. Bank 2 refers to the bank that includes the No. 2 cylinder.

These DTCs are stored when there is an open or short in the A/F sensor circuit, or if A/F sensor output drops.

To detect these problems, the voltage of the A/F 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 A/F sensor is between 0.6 V and 4.5 V, it is considered normal. If the voltage is outside of the specified range, or the admittance is less than the standard value, the ECM will determine that there is a malfunction in the A/F sensor. If the same malfunction is detected in the next driving cycle, the MIL is illuminated and a DTC is stored.

The Air-Fuel Ratio (A/F) sensor varies its output voltage in proportion to the air-fuel ratio. If the A/F sensor impedance (alternating current resistance) or output voltage deviates greatly from the standard range, the ECM determines that there is an open or short in the A/F sensor circuit.

The description can be found in the 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 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.

*: 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 (closes) 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 stores DTC(s).

Scheme 115

The Secondary Air injection (AIR) system consists of an air pump, the Air Switching Valve (ASV), a pressure sensor, the Air Injection Control Driver (AID) and the ECM. For a short time after a cold engine start, the AIR system pumps secondary air to the exhaust port of the cylinder head to purify the exhaust emissions. The secondary air is supplied by the air pump and is pumped to the exhaust port through the ASV.

The AID drives the ASV and the air pump according to command signals transmitted by the ECM. The pressure sensor detects the pressure in the secondary air passage when the AIR system is ON and OFF, and transmits a pressure signal to the ECM.

The AID is not only equipped to drive the pump and valve, but also with a diagnosis function to detect malfunctions in the AIR system circuit.

HINT

As a large current is required to drive the air pump and ASV, an AID is installed to this system.

Scheme 116

Scheme 117

The ECM monitors the pressure in the secondary air passage using the pressure sensor located on the air switching valve in the secondary air injection system.

If there is a defect in the sensor or the sensor circuit, the voltage level deviates from the normal operating range, the ECM interprets this deviation as a malfunction in the pressure sensor or circuit and stores DTC(s).

Refer to DTC P0412. Refer to «DESCRIPTION».

HINT

Air switching valve normal operation

When the Air Switching Valve (ASV) is open, exhaust gas pulsation occurs in the secondary air passage.

When the ASV is closed, exhaust gas pulsation does not occur in the secondary air passage.

The ECM monitors the pressure in the secondary air passage using the pressure sensor connected to the ASV of the Secondary Air Injection (AIR) system.

If either of the following conditions occurs, the ECM interprets it as a malfunction of the AIR system, illuminates the MIL and stores DTC(s)

1. Exhaust gas pulsation is detected by the pressure sensor despite the ECM commanding the ASV to close.
2. Exhaust gas pulsation is not detected by the pressure sensor despite the ECM commanding the ASV to open.

Refer to P2440. Refer to «DESCRIPTION».

The ECM monitors the pressure in the secondary air passage using the pressure sensor located on the Air Switching Valve (ASV) of the Secondary Air Injection (AIR) system. The sensor measures the pressure in the secondary air passage and transmits a signal to the ECM.

If either of the following conditions occurs, the ECM interprets it as a malfunction of the AIR system, illuminates the MIL and stores DTC(s)

1. The pressure indicated by the pressure sensor does not reach threshold levels despite the ECM turning on the air pump.
2. The pressure indicated by the pressure sensor exceeds threshold levels despite the ECM turning off the air pump.

To ensure the accuracy of the EVAP (Evaporative Emission) monitor values, the soak timer, which is built into the ECM, measures 5 hours (+/-15 minutes) from when the engine switch is turned off, before the monitor is run. This allows the fuel to cool down, which stabilizes the EVAP pressure. When 5 hours have elapsed, the ECM turns on.

Scheme 118

5 hours after the engine switch is turned off, the soak timer activates the ECM to begin the EVAP system monitor. 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 (2 trip detection logic).

Refer to DTC P2195. Refer to «DESCRIPTION».

After the engine is warmed up, the ECM performs air-fuel ratio feedback control to maintain the air-fuel ratio at the stoichiometric level. In addition, active A/F control is performed for approximately 10 seconds after the preconditions are met in order to measure the A/F sensor response rate. During active A/F control, the ECM forcibly increases and decreases the injection volume a certain amount, based on the stoichiometric air-fuel ratio learned during normal air-fuel ratio control, and measures the A/F sensor response rate. The ECM receives a signal from the A/F sensor while performing active A/F control and uses it to calculate the A/F sensor response rate deterioration level.

If the A/F sensor response rate deterioration level is less than the threshold, the ECM interprets this as a malfunction and stores DTC(s).

Scheme 119

When the engine switch is turned on (IG), the battery voltage is applied to the IGSW of the ECM. The output signal from the MREL terminal of the ECM causes a current to flow to the coil, closing the contacts of the integration relay (EFI relay) and supplying power to either terminal +B or +B2 of the ECM.

Scheme 120

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Scheme 122

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Scheme 125

Scheme 126

1. INSPECT FUSES (IG2 MAIN, EFI MAIN AND IGN) Remove the IG2 MAIN fuse, EFI MAIN fuse and IGN fuse from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition IG2 MAIN fuse Always Below 1 ohms EFI MAIN fuse Always Below 1 ohms IGN fuse Always Below 1 ohms NG --> CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE OK: Go to next step
2. INSPECT RELAY (IG2, EFI) Remove the integration relay from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 1C-1 - 1B-8 No battery voltage applied to terminals 1B-6 and 1B-7 10 kohms or higher 1C-1 - 1B-8 Battery voltage applied to terminals 1B-6 and 1B-7 Below 1 ohms 1C-1 - 1B-4 No battery voltage applied to terminals 1B-2 and 1B-3 10 kohms or higher 1C-1 - 1B-4 Battery voltage applied to terminals 1B-2 and 1B-3 Below 1 ohms NG --> REPLACE RELAY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Disconnect the C53 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition C53-81 (E1) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (RELAY BLOCK - ECM, MAIN BODY ECU, BATTERY) Disconnect the A38 ECM connector. Disconnect the E2 main body ECU connector. Disconnect the cable from the battery positive (+) terminal. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A38-28 (IGSW) - 1B-8 Always Below 1 ohms 1B-7 - Body ground Always Below 1 ohms Positive (+) battery cable - 1C-1 Always Below 1 ohms E2-11 (IG2D) - 1B-6 Always Below 1 ohms A38-28 (IGSW) or 1B-8 - Body ground Always 10 kohms or higher Positive (+) battery cable or 1C-1 - Body ground Always 10 kohms or higher E2-11 (IG2D) or 1B-6 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. INSPECT ECM (IGSW VOLTAGE) Disconnect the A38 and C53 ECM connectors. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A38-28 (IGSW) - C53-81 (E1) Engine switch on (IG) 11 to 14 V NG --> See step 6 OK --> See step 7
6. CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START (POWER SOURCE MODE DOES NOT CHANGE) Check the smart access system with push-button start. Refer to «Power Source Mode does not Change». NG --> REPAIR SMART ACCESS SYSTEM WITH PUSH-BUTTON START OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (INTEGRATION RELAY - ECM, BATTERY AND BODY GROUND) Disconnect the A38 ECM connector. Disconnect the cable from the battery positive terminal. Remove the integration relay from the engine room relay block. Disconnect the integration relay connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A38-3 (+B) - 1B-4 Always Below 1 ohms A38-2 (+B2) - 1B-4 Always Below 1 ohms A38-34 (MREL) - 1B-2 Always Below 1 ohms 1C-1 - Positive (+) battery cable Always Below 1 ohms 1B-3 - Body ground Always Below 1 ohms A38-3 (+B) or 1B-4 - Body ground Always 10 kohms or higher A38-2 (+B2) or 1B-4 - Body ground Always 10 kohms or higher A38-34 (MREL) or 1B-2 - Body ground Always 10 kohms or higher 1C-1 or Positive (+) battery cable - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 8
8. REPLACE ECM. Refer to «REMOVAL»

The ECM constantly generates 5 V power 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 127

When the VC circuit is short-circuited, the microprocessor in the ECM and sensors that are supplied with 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 for several seconds when the engine switch is first turned on (IG). The MIL goes off when the engine is started.

Scheme 128

Scheme 129

Scheme 130

Scheme 131

Scheme 132

1. CHECK MIL Check that the Malfunction Indicator Lamp (MIL) lights up when turning the engine switch on (IG). OK MIL lights up NG --> See step 2 OK --> SYSTEM OK
2. CHECK COMMUNICATION BETWEEN TECHSTREAM AND ECM Connect the Techstream to the DLC3. Turn the engine switch on (IG) and Techstream on. Check the communication between the Techstream and ECM. RESULT Result Proceed to Communication is possible A Communication is not possible B A --> See step 16 B: Go to next step
3. CHECK MIL (THROTTLE POSITION SENSOR) Disconnect the C4 throttle body connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 17 B: Go to next step
4. CHECK MIL (ACCELERATOR PEDAL POSITION SENSOR) Disconnect the A31 accelerator pedal position sensor connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 18 B: Go to next step
5. CHECK MIL (CANISTER PUMP MODULE) Disconnect the M1 canister pump module connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 19 B: Go to next step
6. CHECK MIL (AIR SWITCHING VALVE for Bank 1) Disconnect the C35 air switching valve connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 20 B: Go to next step
7. CHECK MIL (AIR SWITCHING VALVE for Bank 2) Disconnect the C36 air switching valve connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 21 B: Go to next step
8. CHECK MIL (POWER STEERING OIL PRESSURE SENSOR) Disconnect the C28 power steering oil pressure sensor connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 22 B: Go to next step
9. CHECK MIL (CAMSHAFT POSITION SENSOR) Disconnect the C2 camshaft position sensor connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 23 B: Go to next step
10. CHECK MIL (CRANKSHAFT POSITION SENSOR) Disconnect the C1 crankshaft position sensor connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 24 B: Go to next step
11. CHECK MIL (VVT SENSOR for Intake Side of Bank 1) Disconnect the C20 VVT sensor (for Intake Side of Bank 1) connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 25 B: Go to next step
12. CHECK MIL (VVT SENSOR for Exhaust Side of Bank 1) Disconnect the C22 VVT sensor (for Exhaust Side of Bank 1) connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 26 B: Go to next step
13. CHECK MIL (VVT SENSOR for Intake Side of Bank 2) Disconnect the C21 VVT sensor (for Intake Side of Bank 2) connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 27 B: Go to next step
14. CHECK MIL (VVT SENSOR for Exhaust Side of Bank 2) Disconnect the C23 VVT sensor (for Exhaust Side of Bank 2) connector. Turn the engine switch on (IG). Check the MIL. RESULT Result Proceed to MIL illuminates A MIL does not illuminate B A --> See step 28 B: Go to next step
15. CHECK HARNESS AND CONNECTOR Disconnect the C4 throttle body connector. Disconnect the A31 accelerator pedal position sensor connector. Disconnect the M1 canister pump module connector. Disconnect the C35 air switching valve connector. Disconnect the C36 air switching valve connector. Disconnect the C28 power steering oil pressure sensor connector. Disconnect the C2 camshaft position sensor connector. Disconnect the C1 crankshaft position sensor connector. Disconnect the C20 VVT sensor (for Intake Side of Bank 1) connector. Disconnect the C22 VVT sensor (for Exhaust Side of Bank 1) connector. Disconnect the C21 VVT sensor (for Intake Side of Bank 2) connector. Disconnect the C23 VVT sensor (for Exhaust Side of Bank 2) connector. Disconnect the A38 and C53 ECM connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition C53-80 (VCTA) - Body ground Always 10 kohms or higher A38-57 (VCPA) - Body ground Always 10 kohms or higher A38-59 (VCP2) - Body ground Always 10 kohms or higher C53-66 (VCV2) - Body ground Always 10 kohms or higher C53-67 (VCV1) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 29
16. GO TO MIL CIRCUIT. Refer to «MIL Circuit»
17. REPLACE THROTTLE BODY ASSEMBLY. Refer to «REMOVAL»
18. REPLACE ACCELERATOR PEDAL POSITION SENSOR. Refer to «REMOVAL»
19. REPLACE CHARCOAL CANISTER ASSEMBLY. Refer to «REMOVAL»
20. REPLACE AIR SWITCHING VALVE. Refer to «REMOVAL»
21. REPLACE AIR SWITCHING VALVE. Refer to «REMOVAL»
22. REPLACE POWER STEERING OIL PRESSURE SENSOR. Refer to «REMOVAL»
23. REPLACE CAMSHAFT POSITION SENSOR. Refer to «REMOVAL»
24. REPLACE CRANKSHAFT POSITION SENSOR. Refer to «REMOVAL»
25. REPLACE VVT SENSOR (for Intake Side of Bank 1). Refer to «REMOVAL»
26. REPLACE VVT SENSOR (for Exhaust Side of Bank 1). Refer to «REMOVAL»
27. REPLACE VVT SENSOR (for Intake Side of Bank 2). Refer to «REMOVAL»
28. REPLACE VVT SENSOR (for Exhaust Side of Bank 2). Refer to «REMOVAL»
29. REPLACE ECM. Refer to «REMOVAL»

The fuel pump circuit consists of the ECM, fuel pump and fuel pump ECU (which operates the fuel pump). Based on the engine output, the ECM determines the fuel pump speed. The speed is then converted to a duty signal and sent to the fuel pump ECU. Based on the signal sent from the ECM, the fuel pump ECU adjusts the fuel pump operation speed between 3 settings.

Scheme 133

The fuel injectors are located on the intake manifold. They inject fuel into the cylinders based on the signals from the ECM.

Scheme 134

Scheme 135

Scheme 136

Scheme 137

1. CHECK INJECTOR ASSEMBLY (POWER SOURCE) Disconnect the fuel injector connector. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard Voltage Cylinder Tester Connection Switch Condition Specified Condition No. 1 a5-2 - Ground Engine switch on (IG) 11 to 14 V No. 2 a1-2 - Ground Engine switch on (IG) 11 to 14 V No. 3 a6-2 - Ground Engine switch on (IG) 11 to 14 V No. 4 a2-2 - Ground Engine switch on (IG) 11 to 14 V No. 5 a7-2 - Ground Engine switch on (IG) 11 to 14 V No. 6 a3-2 - Ground Engine switch on (IG) 11 to 14 V No. 7 a8-2 - Ground Engine switch on (IG) 11 to 14 V No. 8 a4-2 - Ground Engine switch on (IG) 11 to 14 V NG --> See step 4 OK: Go to next step
2. INSPECT FUEL INJECTOR ASSEMBLY Inspect the fuel injector. Refer to «INSPECTION». NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (FUEL INJECTOR ASSEMBLY - ECM) Disconnect the fuel injector connector. Disconnect the C53 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Cylinder Tester Connection Condition Specified Condition No. 1 a5-1 - Body ground Always 10 kohms or higher a5-1 - C53-86 (#10) Always Below 1 ohms No. 2 a1-1 - Body ground Always 10 kohms or higher a1-1 - C53-109 (#20) Always Below 1 ohms No. 3 a6-1 - Body ground Always 10 kohms or higher a6-1 - C53-85 (#30) Always Below 1 ohms No. 4 a2-1 - Body ground Always 10 kohms or higher a2-1 - C53-108 (#40) Always Below 1 ohms No. 5 a7-1 - Body ground Always 10 kohms or higher a7-1 - C53-84 (#50) Always Below 1 ohms No. 6 a3-1 - Body ground Always 10 kohms or higher a3-1 - C53-107 (#60) Always Below 1 ohms No. 7 a8-1 - Body ground Always 10 kohms or higher a8-1 - C53-83 (#70) Always Below 1 ohms No. 8 a4-1 - Body ground Always 10 kohms or higher a4-1 - C53-106 (#80) Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
4. INSPECT FUSE (INJ, IG2 MAIN) Remove the INJ fuse and IG2 MAIN fuse from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition INJ fuse Always Below 1 ohms IG2 MAIN fuse Always Below 1 ohms NG --> CHECK FOR SHORT IN ALL HARNESSES AND CONNECTORS CONNECTED TO FUSE AND REPLACE FUSE OK: Go to next step
5. INSPECT INTEGRATION RELAY (IG2) Inspect the integration relay. Refer to «ON-VEHICLE INSPECTION - Step 2». NG --> REPLACE INTEGRATION RELAY OK --> REPAIR OR REPLACE HARNESS OR CONNECTOR (INTEGRATION RELAY - FUEL INJECTOR ASSEMBLY)
6. REPLACE FUEL INJECTOR ASSEMBLY. Refer to «REMOVAL»
7. REPLACE ECM. Refer to «REMOVAL»

The cranking holding control system provides current to the starter when the ECM detects the engine switch start signal (STSW). When the ECM performs a firing judgment, the system cuts current to the starter. When an ECM receives the STSW signal, it turns on the ACC cut, which prevents flickering of the combination meter, clock, audio system, etc. Also, the ECM sends a signal to the ECM STAR terminal. Then the STAR output signal travels through the Park/Neutral Position (PNP) switch to the starter relay, causing the starter to activate.

When the engine is cranking, the starter operation signal is sent to the ECM STA terminal.

Scheme 138

Scheme 139

Scheme 140

Scheme 141

Scheme 142

1. CHECK CRANKING Check the cranking of the engine. RESULT Result Proceed to Cranking possible and holding control operates A Does not crank B Cranking possible but holding control does not operate C C --> See step 11 B --> See step 2 A --> See step 14
2. READ VALUE USING TECHSTREAM (STARTER SIGNAL) Connect the Techstream to the DLC3. Turn the engine switch on (IG). Turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Data List / Starter Signal. Check the value displayed on the Techstream when the engine switch is turned to the START. Standard Engine Switch Position Display (Starter Signal) On (IG) OFF START ON NG --> See step 7 OK: Go to next step
3. INSPECT STARTER RELAY (ST) Remove the starter relay (ST) from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 3 - 5 No battery voltage applied to terminals 1 and 2 10 kohms or higher 3 - 5 Battery voltage applied to terminals 1 and 2 Below 1 ohms NG --> REPLACE STARTER RELAY (ST) OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (ST RELAY - PNP SWITCH) Remove the starter relay (ST) from the engine room relay block. Disconnect the C19 PNP switch. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition ST relay (1) - C19-5 Always Below 1 ohms ST relay (1) or C19-5 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
5. CHECK STARTER RELAY (POWER SOURCE) Remove the ST relay from the engine room relay block. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition ST relay (2) - ST relay (5) Always 11 to 14 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER RELAY (ST) - BATTERY, BODY GROUND) OK: Go to next step
6. INSPECT STARTER Inspect the starter. Refer to «INSPECTION»(/lexus/lx/j200-2007-2012/remont/starter/#starting-service-information) . NG --> See step 15 OK --> REPAIR OR REPLACE HARNESS OR CONNECTOR (STARTER - STARTER RELAY (ST), BATTERY)
7. INSPECT STARTER CUT RELAY (ST CUT) Remove the starter cut relay (ST CUT) from the engine room relay block. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 3 - 5 No battery voltage applied to terminals 1 and 2 10 kohms or higher 3 - 5 Battery voltage applied to terminals 1 and 2 Below 1 ohms NG --> REPLACE STARTER CUT RELAY (ST CUT) OK: Go to next step
8. CHECK HARNESS AND CONNECTOR (ST CUT RELAY - PNP SWITCH, ECM) Remove the starter cut relay (ST CUT) from the engine room relay block. Disconnect the C19 PNP switch connector. Disconnect the C53 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition ST CUT relay (5) - C53-16 (STAR) Always Below 1 ohms ST CUT relay (3) - C19-4 Always Below 1 ohms ST CUT relay (5) or C53-16 (STAR) - Body ground Always 10 kohms or higher ST CUT relay (3) or C19-4 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
9. INSPECT PARK/NEUTRAL POSITION SWITCH Inspect the Park/Neutral Position (PNP) switch. Disconnect the C19 PNP switch connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 4 (B) - 5 (L) Shift lever in P Below 1 ohms Shift lever in N Below 1 ohms NG --> See step 16 OK: Go to next step
10. CHECK HARNESS AND CONNECTOR (PNP SWITCH - ECM) Disconnect the C19 PNP switch connector. Disconnect the A38 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition C19-5 - A38-46 (STA) Always Below 1 ohms C19-5 or A38-46 (STA) - Body ground Always 10 kohms or higher RESULT Result Proceed to NG A OK B B --> See step 17 A --> REPAIR OR REPLACE HARNESS OR CONNECTOR
11. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - ECM) Disconnect the E4 main body ECU connector. Disconnect the A38 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E4-4 (STSW) - A38-14 (STSW) Always Below 1 ohms E4-4 (STSW) or A38-14 (STSW) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
12. CHECK HARNESS AND CONNECTOR (ST CUT RELAY - PNP SWITCH, ECM) Remove the starter cut relay (ST CUT) from the engine room relay block. Disconnect the C19 PNP switch connector. Disconnect the C53 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition ST CUT relay (5) - C53-16 (STAR) Always Below 1 ohms ST CUT relay (3) - C19-4 Always Below 1 ohms ST CUT relay (5) or C53-16 (STAR) - Body ground Always 10 kohms or higher ST CUT relay (3) or C19-4 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 13
13. REPLACE ECM. Refer to «REMOVAL»
14. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»
15. REPAIR OR REPLACE STARTER. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/starter/#starting-service-information)
16. REPLACE PARK/NEUTRAL POSITION SWITCH. Refer to «REMOVAL»
17. REPLACE ECM Replace the ECM. Refer to «REMOVAL». NEXT: Go to next step
18. CONFIRM WHETHER MALFUNCTION HAS BEEN SUCCESSFULLY REPAIRED Check the starter operation. OK Malfunction has been repaired successfully. NG --> See step 19 OK --> END
19. GO TO SMART ACCESS SYSTEM WITH PUSH-BUTTON START (ENGINE DOES NOT START). Refer to «Engine does not Start»

This circuit opens and closes the Intake Air Control Valve (IACV) in response to the engine load in order to increase the intake efficiency (ACIS: Acoustic Control Induction System).

Scheme 143

Scheme 144

Scheme 145

Scheme 146

1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE VSV FOR ACIS) Disconnect the vacuum hose from port F on the vacuum switching valve (for ACIS). Connect the Techstream to the DLC3. Start the engine. Enter the following menus: Powertrain / Engine and ECT / Active Test / Active the VSV for Intake Control. Operate the VSV for ACIS. Check the VSV air flow when switching the VSV. OK Test Condition Specified Condition VSV is ON Air from port E flows out through port F VSV is OFF Air from port E flows out through air filter NG --> See step 5 OK: Go to next step
2. CHECK VACUUM HOSES (VACUUM SWITCHING VALVE - INTAKE AIR CONTROL VALVE, INTAKE MANIFOLD) NG --> REPAIR OR REPLACE VACUUM HOSES OK: Go to next step
3. INSPECT INTAKE MANIFOLD (INTAKE AIR CONTROL VALVE) Inspect the intake air control valve. Refer to «ON-VEHICLE INSPECTION»(/lexus/lx/j200-2007-2012/remont/mechanical/#intake-inspection) . NG --> See step 8 OK --> See step 4
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»
5. INSPECT VACUUM SWITCHING VALVE Inspect the vacuum switching valve. Refer to «ON-VEHICLE INSPECTION»(/lexus/lx/j200-2007-2012/remont/exhaust/#exhaust-service-information) . NG --> See step 9 OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (VACUUM SWITCHING VALVE - ECM AND INTEGRATION RELAY) Remove the EFI NO. 2 fuse from the engine room relay block. Check the EFI NO. 2 fuse. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition EFI NO. 2 fuse Always Below 1 ohms Reinstall the EFI NO. 2 fuse. Disconnect the C38 intake air control valve connector. Disconnect the C53 ECM connector. Remove the integration relay from the engine room relay block. Disconnect the 1B integration relay connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition C38-2 - C53-62 (ACIS) Always Below 1 ohms C38-1 - 1B-4 Always Below 1 ohms C38-2 or C53-62 (ACIS) - Body ground Always 10 kohms or higher C38-1 or 1B-4 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
7. REPLACE ECM. Refer to «REMOVAL»
8. REPLACE INTAKE MANIFOLD. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/exhaust/#exhaust-service-information__removal)
9. REPLACE VACUUM SWITCHING VALVE. Refer to «REMOVAL»(/lexus/lx/j200-2007-2012/remont/exhaust/#exhaust-service-information__removal)

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunction detections by the ECM. When the engine switch is turned 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 first turned on (IG), the MIL should be illuminated and should then turn off when the engine is started. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.

Scheme 147

Scheme 148

Scheme 149

1. CHECK THAT MIL IS ILLUMINATED Perform troubleshooting in accordance with the table below. RESULT Result Proceed to MIL remains ON A MIL does not illuminate B B --> See step 5 A: Go to next step
2. CHECK WHETHER MIL TURNS OFF Connect the Techstream to the DLC3. Turn the engine switch on (IG) and turn the Techstream on. Enter the following menus: Powertrain / Engine and ECT / Trouble Codes. Check if any DTCs are output. Note down any DTCs. Clear DTCs. Refer to «DTC CHECK / CLEAR». Check if the MIL goes off. Standard MIL goes off NG --> See step 3 OK --> See step 8
3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) Disconnect the A38 ECM connector. Turn the engine switch on (IG). Check that the MIL is not illuminated. OK MIL is not illuminated. NG --> See step 4 OK --> See step 9
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM) Disconnect the A38 ECM connector. Disconnect the E77 combination meter connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A38-24 (W) or E77-18 (CHK) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 10
5. CHECK THAT MIL IS ILLUMINATED Check if the MIL is illuminated when the engine switch is turned on (IG). OK MIL is illuminated. NG --> See step 6 OK --> SYSTEM OK
6. CHECK THAT ENGINE STARTS Turn the engine switch on (IG). Start the engine. RESULT Result Proceed to Engine starts A Engine does not start* B HINT: *: The Techstream cannot communicate with the ECM. B --> See step 11 A: Go to next step
7. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM) Disconnect the A38 ECM connector. Disconnect the E77 combination meter connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A38-24 (W) - E77-18 (CHK) Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 12
8. REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to «DIAGNOSTIC TROUBLE CODE CHART»
9. REPLACE ECM. Refer to «REMOVAL»
10. REPLACE COMBINATION METER ASSEMBLY. Refer to «REMOVAL»
11. GO TO VC OUTPUT CIRCUIT. Refer to «VC Output Circuit»
12. REPLACE COMBINATION METER ASSEMBLY. Refer to «REMOVAL»

See also:
• ON-VEHICLE INSPECTION - Step 4
• REMOVAL
• ON-VEHICLE INSPECTION - Step 1
• REMOVAL
• ON-VEHICLE INSPECTION - Step 2
• INSPECTION
• ON-VEHICLE INSPECTION