Engine Control System (Diagnostic Codes (P01604-U101) & Circuit Tests)): Overview Lexus ES XV40 facelift

DESCRIPTION

This DTC is stored when the engine does not start even though the STA signal is input or when the engine takes a long time to start, and when the engine speed is low or the engine stalls just after the engine starts.

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 there is engine starting trouble due to running out of fuel.

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1. Reference waveforms showing a normal cold engine start
2. Reference waveforms showing a normal warm engine start
3. Reference waveforms showing an engine stop after normal idling
4. Reference values when there is an air leak in the intake system during starting difficulty FREEZE FRAME DATA P1604 STARTABILITY MALFUNCTION Engine Current P1604: Startability Malfunction Time Freeze Frame Data Item Data1 Data2 Data3 Data4 Data5 Unit Engine Speed 1489 986 345 186 124 rpm Calculate Load 36.2 28.2 31.4 92.4 94.6 % Vehicle Load 7.9 7.9 9.2 7.2 6.0 % MAF 10.12 5.04 2.79 0.81 0.68 gm/sec Atmosphere Pressure -0 -0 -0 -0 -0 kPa Coolant Temp 185 185 185 185 185 F Intake Air 102 102 102 102 102 F Battery Voltage 13.222 13.300 12.109 11.972 11.854 V Throttle Sensor Volt % 16.5 16.5 16.0 15.6 15.6 % Throttle Sensor #2 Volt % 48.2 48.2 47.8 47.2 47.2 % Throttle Sensor Position 0.0 0.0 0.0 0.0 0.0 % Throttle Motor DUTY 16.5 16.5 16.0 15.6 15.6 % Injector (Port) 3628 2620 2744 2744 2744 μs Injection Volume (Cylinder 1) 3.062 0.226 0.226 0.226 0.226 ml Fuel Pump/Speed Status ON ON ON ON ON EVAP (Purge) VSV 0.0 0.0 0.0 0.0 0.0 % Evap Purge Flow 0.0 0.0 0.0 0.0 0.0 % Purge Density Learn Value 0.000 0.000 0.000 0.000 0.000 EVAP System Vent Valve OFF OFF OFF OFF OFF EVAP purge VSV OFF OFF OFF OFF OFF Purge Cut VSV Duty 0.0 0.0 0.0 0.0 0.0 % Target Air-Fuel Ratio 0.998 0.998 0.998 0.998 0.998 AF Lambda B1S1 0.999 0.999 0.999 0.999 0.999 AF Lambda B2S1 0.997 0.997 0.997 0.998 0.998 AFS Voltage B1S1 3.258 3.258 3.258 3.258 3.258 V AFS Voltage B2S1 3.251 3.251 3.251 3.253 3.253 V O2S B1S2 0.000 0.000 0.000 0.000 0.000 V O2S B2S2 0.015 0.015 0.015 0.000 0.000 V Short FT #1 0.000 0.000 0.000 0.000 0.000 % Long FT #1 8.782 4.354 -2.665 -2.665 -2.665 % Total FT #1 0.058 0.058 0.058 0.058 0.058 Sort FT #2 0.000 0.000 0.000 0.000 0.000 % Long FT #2 9.264 4.587 -2.462 -2.462 -2.462 % Total FT #2 0.062 0.062 0.062 0.062 0.062 Fuel System Status #1 OL OL OL OL OL Fuel System Status #2 OL OL OL OL OL IGN Advance 0.0 10.5 16.5 18.0 18.0 deg Knock Feedback Value -1.5 -1.5 -1.5 -1.5 -1.5 CA Knock Correct Learn Value 17.0 17.0 17.0 17.0 17.0 CA Starter Signal Close Close Close Close Close Ambient Temperature 70 70 70 70 70 F

MONITOR DESCRIPTION

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

The 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 sensor, which is mounted on the throttle body assembly. The throttle position 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 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 a DTC.

Example

1. 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 a DTC.
2. If the malfunction is not repaired successfully, a DTC is stored when the engine is quickly revved to a high engine speed several times after the engine has idled for 5 seconds after engine start.

The idling speed is controlled by the Electronic Throttle Control System (ETCS).

The ETCS is comprised of a throttle actuator, which operates the throttle valve, and a throttle position sensor, which detects the opening amount of the throttle valve.

The ECM controls the throttle actuator to adjust the throttle valve opening amount so that the idling speed is maintained at the target idling speed.

If there are deposits in the throttle valve, the necessary ISC flow rate for idling is maintained using the ISC learning value and feedback as a decrease in the ISC flow rate may cause engine stall or unstable idling. The ECM stores this DTC if the ISC learning value approaches its limit.

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 sensor, which is mounted on the throttle body assembly. The throttle position 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 electronic throttle control system does not use a throttle cable.

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

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 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 electronic throttle control system and cuts off the current to the throttle actuator.

When the voltage becomes unstable, the electronic throttle control system 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

This electronic throttle control system does not use a throttle cable.

Scheme 39

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 is composed of the throttle actuator, throttle position sensor, accelerator pedal position sensor, and ECM. The ECM operates the throttle actuator to regulate the throttle valve in response to driver inputs. The throttle position 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 throttle position sensor signal. The actual opening angle is compared to the target opening angle commanded by the ECM. If the difference between these 2 values is outside the standard range, the ECM interprets this as a malfunction in the electronic throttle control system. 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 depressing the accelerator pedal (fully open the throttle valve).

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

The Accelerator Pedal Position (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 V and 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 40

HINT

When any of these DTCs are set, check the Accelerator position sensor voltage by entering the following menus on the Techstream: Powertrain / Engine / Data List / Accel Sensor Out No. 1 and Accel Sensor Out No. 2.

HINT

1. Accelerator pedal positions are expressed as voltages.
2. AP denotes Accelerator Pedal.

1. When either of the output voltages 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 sets a DTC. 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 set. If the malfunction is not repaired successfully, a DTC is set 2 seconds after the engine is next started.

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

The Accelerator Pedal Position (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 V and 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.

The accelerator pedal position sensor is mounted on the accelerator pedal bracket. The accelerator pedal position sensor has 2 sensor elements and 2 signal outputs: VPA and VPA2. VPA is used to detect the actual accelerator pedal angle (used for engine control) and VPA2 is used to detect malfunctions in VPA. When the difference between the output voltages of VPA and VPA2 deviates from the standard, the ECM determines that the accelerator pedal position sensor is malfunctioning. The ECM turns on the MIL and the DTC is set.

HINT

1. Although the DTC titles include oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
2. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F sensor generates 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 oxygen concentration detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

A three-way catalytic converter (TWC) is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the TWC to function effectively, it is necessary to keep the air-fuel ratio of the engine near the stoichiometric air-fuel ratio.

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

Scheme 41

HINT

1. DTCs P2195 and P2196 indicate malfunctions related to the bank 1 A/F sensor circuit.
2. DTCs P2197 and P2198 indicate malfunctions related to the bank 2 A/F sensor circuit.
3. Bank 1 refers to the bank that includes cylinder No. 1.
4. Bank 2 refers to the bank that includes cylinder No. 2.
5. When any of these DTCs are set, check the A/F sensor output voltage by entering the following menus on the Techstream: Powertrain / Engine / Data List / 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 AF+ and AF- terminals of the ECM to a constant level. Therefore, the A/F sensor output voltage cannot be confirmed without using the Techstream.
8. If an A/F sensor malfunction is detected, the ECM sets a DTC.

Scheme 42

1. Sensor voltage detection monitor
2. 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 sets a DTC. Example: If the A/F sensor voltage output is less than 2.8 V (very rich condition) and HO2 sensor output voltage falls from 0.59 V or more to less than 0.21 V for 5 seconds, the ECM sets DTC P2196 or P2198. Alternatively, if the A/F sensor output voltage is more than 3.8 V (very lean condition) and HO2 sensor output voltage rise from less than 0.21 V to 0.59 V or more for 5 seconds, DTC P2195 or P2197 is set. 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 more for more than 3 seconds of cumulative time, the ECM interprets this as a malfunction in the A/F sensor and sets DTC P2195 or P2197 (high-side stuck). If the A/F sensor output is less than 1.4 mA for more than 3 seconds of cumulative time, the ECM sets DTC P2196 or P2198 (low-side stuck).

HINT

1. Although the DTC titles include oxygen sensor, these DTCs relate to the Air-Fuel Ratio (A/F) sensor.
2. Sensor 1 refers to the sensor mounted in front of the Three-Way Catalytic Converter (TWC) and located near the engine assembly.

The A/F sensor generates 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 oxygen concentration detection. In addition, the sensor and heater portions are narrower than the conventional type. The heat generated by the heater is conducted to the solid electrolyte through the alumina, therefore the sensor activation is accelerated.

A three-way catalytic converter (TWC) is used in order to convert the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) into less harmful substances. To allow the TWC to function effectively, it is necessary to keep the air-fuel ratio of the engine near the stoichiometric air-fuel ratio.

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

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 cylinder No. 1.
4. Bank 2 refers to the bank that includes cylinder No. 2.

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 malfunction in the A/F sensor circuit.

The circuit description can be found in the EVAP (Evaporative Emission) system. Refer to EVAP System.

5 hours *1 after the engine switch is turned off, the electric leak detection pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The ECM monitors for leaks and actuator malfunctions based on the EVAP pressure.

HINT

*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.

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

Scheme 43

The vent valve turns ON (closes) and the EVAP (Evaporative Emission) system pressure is then measured by the ECM, using the 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 44

The soak timer operates after the engine switch is turned off. When a 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 45

1. 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. 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 communications with each other via the Controller Area Network (CAN). The TCM sends signals to the ECM concerning required engine rpm, required engine torques, warning indicators in the combination meter, DTCs and other data. The ECM sends signals to the TCM concerning engine rpm, opening angles of the throttle valve, temperature of intake air, temperature of engine coolant, engine torques 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.

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

If the engine switch is turned off, the ECM holds the EFI relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

When the engine switch is turned on (IG), voltage from the ECM's MREL terminal applies to the engine room junction block (EFI relay). This causes the contacts of the engine room junction block (EFI relay) to close, which supplies power to terminal +B or +B2 of the ECM.

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1. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Disconnect the B12 ECM connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Condition E1 (B12-81) - Body ground Below 1 ohms Reconnect the ECM connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK ENGINE ROOM JUNCTION BLOCK (EFI RELAY VOLTAGE) Remove the engine room junction block from the engine room R/B. Turn the engine switch on (IG). Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Specified Condition 1E-6 - Body ground 9 to 14 V OK --> See step 5 NG: Go to next step
3. INSPECT EFI MAIN FUSE Remove the EFI MAIN fuse from the engine room R/B. Measure the EFI MAIN fuse resistance. Standard resistance Below 1 ohms Reinstall the EFI MAIN fuse. NG --> REPLACE EFI MAIN FUSE OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (ENGINE ROOM RELAY BLOCK - BATTERY) Disconnect the negative battery terminal. Disconnect the positive battery terminal. Remove the engine room junction block from the engine room R/B. Measure the resistance according to the value(s) in the table below. Standard resistance (Check for open) Tester Connection Specified Condition 1G-1 - Positive battery terminal Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition 1G-1 or Positive battery terminal - Body ground 10 kohms or higher Reinstall the engine room junction block. Reconnect the positive battery terminal. Reconnect the negative battery terminal. OK --> See step 13 NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
5. INSPECT ENGINE ROOM JUNCTION BLOCK (EFI RELAY) Remove the engine room junction block from the engine room R/B. Measure the resistance between the terminals. Standard resistance Tester Connection Specified Condition 1E-6 - 1E-12 10 kohms or higher 1E-6 - 1E-12 Below 1 ohms (Apply battery voltage between terminals 1E-9 and 1E-10) Reinstall the engine room junction block. NG --> REPLACE ENGINE ROOM JUNCTION BLOCK OK: Go to next step
6. INSPECT EFI NO. 2 FUSE Remove the EFI No. 2 fuse from the engine room R/B. Measure the EFI No. 2 fuse resistance. Standard resistance Below 1 ohms Reinstall the EFI No. 2 fuse. NG --> REPLACE EFI NO. 2 FUSE OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (ECM - ENGINE ROOM JUNCTION BLOCK) Disconnect the A10 ECM connector. Remove the engine room junction block from the engine room R/B. Measure the resistance according to the value(s) in the table below. Standard resistance (Check for open) Tester Connection Specified Condition 1E-6 - +B (A10-2) Below 1 ohms 1E-6 - +B2 (A10-1) Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition 1E-6 or +B (A10-2) - Body ground 10 kohms or higher 1E-6 or +B2 (A10-1) - Body ground 10 kohms or higher Reinstall the engine room junction block. Reconnect the ECM connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. INSPECT ECM (IGSW VOLTAGE) Disconnect the A10 ECM connector. Measure the voltage according to the value(s) in the table below. Standard voltage Tester Connection Specified Condition IGSW (A10-28) - Body ground 9 to 14 V Reconnect the ECM connector. OK --> See step 11 NG: Go to next step
9. INSPECT IG2 RELAY Remove the IG2 relay from the engine room R/B. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Condition 3 - 5 10 kohms or higher 3 - 5 Below 1 ohms (Apply battery voltage between terminals 1 and 2) Reinstall the IG2 relay. NG --> REPLACE IGNITION RELAY NO. 2 OK: Go to next step
10. CHECK HARNESS AND CONNECTOR (IG2 RELAY - BODY GROUND) Remove the IG2 relay from the engine room R/B. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Condition IG2 relay terminal 2 - Body ground Below 1 ohms Reinstall the IG2 relay. Result Result Proceed to OK A NG B A --> GO TO APPROPRIATE SERVICE INFORMATION FOR SMART ACCESS SYSTEM WITH PUSH-BUTTON START B --> REPAIR OR REPLACE HARNESS OR CONNECTOR
11. CHECK HARNESS AND CONNECTOR (ECM - BODY GROUND) Disconnect the A10 ECM connector. Measure the resistance according to the value(s) in the table below. Standard resistance Tester Connection Specified Condition MREL (A10-44) - Body ground Below 1 ohms Reconnect the ECM connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
12. REPLACE ECM. Refer to «REMOVAL»(ref-396635-S35871318042011050900000)
13. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-396630-S03331147362011050900000)

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 short-circuited, 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 for several seconds when the engine switch is first turned on (IG). The MIL goes off when the engine is started.

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In the diagram below, when the engine is cranked, current flows from terminal ST1 (STR) of the engine switch (power source control ECU) to the starter relay (Marking: ST) coil and also current flows to terminal STA of the ECM (STA signal).

When the STA signal and NE signal are input to the ECM, Tr is turned ON, current flows to the coil of the circuit opening relay (Marking: C/OPN), the relay switches on, power is supplied to the fuel pump and the fuel pump operates.

While the NE signal is generated (engine running), the ECM keeps Tr ON (circuit opening relay ON) and the fuel pump also keeps operating.

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1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE C/OPN RELAY) Connect the Techstream to the DLC3. Turn the engine switch on (IG) and turn the Techstream on. Select the following menu items: Powertrain / Engine / Active Test / Control the Fuel Pump / Speed. Check whether the fuel pump operation sound occurs when performing the Active Test on the Techstream. OK Fuel pump operating sound occurs. NG --> See step 3 OK: Go to next step
2. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-396630-S03331147362011050900000)
3. CHECK ECM POWER SOURCE CIRCUIT NG --> REPAIR OR REPLACE ECM POWER SOURCE CIRCUIT OK: Go to next step
4. INSPECT ENGINE ROOM JUNCTION BLOCK (C/OPN RELAY) Remove the integration relay from the engine room relay block. Inspect the C/OPN relay. Measure the C/OPN relay resistance. Standard resistance Tester Connection Specified Condition 1E-7 - 1E-13 10 kohms or higher Below 1 ohms (Apply battery voltage between terminals 1D-12 and 1E-8) Reinstall the integration relay. NG --> REPLACE ENGINE ROOM JUNCTION BLOCK OK: Go to next step
5. INSPECT ECM (FC VOLTAGE) Disconnect the A10 and B12 ECM connectors. Measure the voltage between the terminals of the A10 and B12 ECM connectors. Standard voltage Tester Connection Specified Condition FC (A10-7) - E1 (B12-81) 9 to 14 V Reconnect the ECM connectors. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - BATTERY) OK: Go to next step
6. INSPECT FUEL PUMP NG --> See step 9 OK: Go to next step
7. CHECK HARNESS AND CONNECTOR (C/OPN RELAY - FUEL PUMP - BODY GROUND) Check the harness and the connectors between the engine room relay block and the fuel pump. Disconnect the integration relay connector. Disconnect the L13 fuel pump connector. Measure the resistance. Standard resistance (Check for open) Tester Connection Specified Condition 1E-13 - L13-4 (Fuel pump) Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition 1E-13 or L13-4 (Fuel pump) - Body ground 10 kohms or higher Check the harness and the connectors between the fuel pump and body ground. Disconnect the L13 fuel pump connector. Measure the resistance. Standard resistance (Check for open) Tester Connection Specified Condition L13-5 (Fuel pump) - Body ground Below 1 ohms Reconnect the integration relay connector. Reconnect the fuel pump connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
8. REPLACE ECM. Refer to «REMOVAL»(ref-396635-S35871318042011050900000)
9. REPLACE FUEL PUMP. Refer to «REMOVAL»(ref-396644-S29992404232011050900000)

The cranking holding control system provides current to the starter when the ECM detects the engine switch start signal (STSW). When the ECM judges that the engine has started , the system cuts current to the starter. When the ECM receives the STSW signal, the ACC (Accessory) relay is turned off to, prevents flickering of the combination meter, clock and audio system. Also, the STAR output signal travels through the ST cut relay and the park/neutral position switch assembly to the ST relay, causing the starter to activate.

When the engine is cranking, the starter operation signal is received by the STA terminal of the ECM.

Scheme 60

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

When the engine speed is between 0 and 4450 rpm and the throttle valve opening angle is 60° or more, the ECM supplies current to the VSV (ON status), to close the IACV. Under other conditions, the VSV is usually OFF and the IACV is open.

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1. PERFORM ACTIVE TEST USING TECHSTREAM (OPERATE VSV FOR ACIS) Connect the Techstream to the DLC3. Start the engine and turn the Techstream on. Select the following menu items: Powertrain / Engine / Active Test / Activate the VSV for Intake Control. Operate the VSV for AICS. OK Operational noise can be heard. OK --> See step 5 NG: Go to next step
2. CHECK INTAKE AIR CONTROL VALVE (OPERATION) Disconnect the B41 VSV for ACIS connector. Apply battery voltage between the terminals of the air intake control valve connector. Check the air intake valve operation. OK Operational noise can be heard. NG --> REPLACE INTAKE AIR SURGE TANK OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (VSV FOR ACIS - ECM, VSV FOR ACIS - EFI RELAY) Check the wire harness and connectors between the VSV for ACIS and ECM. Disconnect the B41 VSV for ACIS connector. Disconnect the B12 ECM connector. Measure the resistance according to the value(s) in the table below. Standard resistance (Check for open) Tester Connection Specified Condition VSV for ACIS (B41-1) - ACIS (B12-107) Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition VSV for ACIS (B41-1) or ACIS (B12-107) - Body ground 10 kohms or higher Reconnect the VSV for ACIS connector. Reconnect the ECM connector. Check the EFI No. 3 fuse. Remove the EFI No. 3 fuse from the engine room R/B. Measure the EFI No. 3 fuse resistance. Standard resistance Below 1 ohms Reinstall the EFI No. 3 fuse. Check the wire harness between the VSV for ACIS connector and EFI relay. Remove the engine room junction block from the engine room R/B. Disconnect the B41 VSV for ACIS connector. Measure the resistance between the terminals. Standard resistance (Check for open) Tester Connection Specified Condition VSV for ACIS (B41-2) - 1E-6 Below 1 ohms Reinstall the engine room junction block. Reconnect the VSV connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. REPLACE ECM. Refer to «REMOVAL»(ref-396635-S35871318042011050900000)
5. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-396630-S03331147362011050900000)

The air cleaner is equipped with two inlets, one of which is opened or closed by the Air Intake Control Valve (AICV). This system reduces intake noise and increases engine power at low-to-high engine speed range.

When the engine is operating in the low-to-mid speed range, this control operates the AICV 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 AICV.

Scheme 64

Scheme 65

Scheme 66

1. PERFORM ACTIVE TEST USING TECHSTREAM (VSV FOR AICV) Turn the engine switch on (IG) and turn the Techstream on. Select the following menu items: Powertrain / Engine / Active Test / Activate the VSV for ACIS. Check the operation of the VSV when the VSV is operated by the Techstream. Standard Techstream Operation Specified Condition VSV is ON Air from port E flows out through port F VSV is OFF Air from port E flows out through the air filter OK --> See step 4 NG: Go to next step
2. CHECK VSV (FOR AICV) Inspect the intake air control valve assembly. Refer to «INSPECTION»(/lexus/es/xv40-facelift-2009-2012/remont/mechanical/#vacuum-switching-valve-service-information) . NG --> REPLACE INTAKE AIR CONTROL VALVE ASSEMBLY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (VSV FOR AICV - ECM, VSV FOR AICV - EFI RELAY) Check the wire harness between the VSV for AICV connector and the ECM connector. Disconnect the A47 VSV for AICV connector. Disconnect the A10 ECM connector. Measure the resistance according to the value(s) in the table below. Standard resistance (Check for open) Tester Connection Specified Condition VSV for AICV (A47-2) - AICV (A10-4) Below 1 ohms Standard resistance (Check for short) Tester Connection Specified Condition VSV for AICV (A47-2) or AICV (A10-4) - Body ground 10 kohms or higher Reconnect the ECM connector. Check the EFI No. 3 fuse. Remove the EFI No. 3 fuse from the engine room R/B. Measure the resistance of the EFI No. 3 fuse. Standard resistance Below 1 ohms Reinstall the EFI No. 3 fuse. Check the wire harness between the VSV for AICV and the EFI relay. Remove the engine room junction block from the engine room R/B. Measure the resistance between the terminals of the wire harness side connectors. Standard resistance (Check for open) Tester Connection Specified Condition VSV for AICV (A47-1) - 1E-6 Below 1 ohms Reconnect the VSV for AICV connector. Reinstall the engine room junction block. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. INSPECT VACUUM TANK Inspect the vacuum tank. Refer to «INSPECTION - Step 2»(/lexus/es/xv40-facelift-2009-2012/remont/mechanical/#intake-inspection) . NG --> REPAIR OR REPLACE AIR CLEANER CAP OK: Go to next step
5. REPLACE ECM. Refer to «REMOVAL»(ref-396635-S35871318042011050900000)

The MIL (Malfunction Indicator Lamp) is used to indicate vehicle malfunctions detected 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. If the MIL remains illuminated or is not illuminated, conduct the following troubleshooting procedure using the Techstream.

Scheme 67

Scheme 68

1. CHECK THAT MIL IS ILLUMINATED Perform troubleshooting in accordance with the table below: Result Conditions 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. Select the following menu items: Powertrain / Engine / Trouble Codes. Check if any DTCs have been stored. Note down any DTCs. Clear the DTCs. Refer to «DTC CHECK / CLEAR»(ref-396630-S12048003312011050900000). Check if the MIL goes off. Standard MIL goes off. OK --> See step 8 NG: Go to next step
3. CHECK HARNESS AND CONNECTOR (CHECK FOR SHORT IN WIRE HARNESS) Disconnect the A10 ECM connector. Turn the engine switch on (IG). Check that the MIL is not illuminated. OK MIL is not illuminated. Reconnect the ECM connector. OK --> See step 9 NG: Go to next step
4. CHECK HARNESS AND CONNECTOR (COMBINATION METER - ECM) Disconnect the A10 ECM connector. Disconnect the E20 combination meter connector. Measure the resistance. Standard resistance (Check for short) Tester Connection Specified Condition W (A10-24) or CHK (E20-4) - Body ground 10 kohms or higher Reconnect the ECM connector. Reconnect the combination meter connector. OK --> REPAIR OR REPLACE COMBINATION METER ASSEMBLY NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR
5. CHECK THAT MIL IS ILLUMINATED Check if the MIL is illuminated when the engine switch is turned on (IG). OK MIL is illuminated. OK --> SYSTEM OK NG: Go to next step
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: *: Techstream cannot communicate with the ECM. B --> See step 10 A: Go to next step
7. INSPECT COMBINATION METER ASSEMBLY (MIL CIRCUIT) Check the MIL circuit. Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-396653-S28211457612011050900000). NG --> REPAIR OR REPLACE COMBINATION METER ASSEMBLY OK --> CHECK AND REPLACE HARNESS AND CONNECTOR (COMBINATION METER - ECM)
8. REPAIR CIRCUITS INDICATED BY OUTPUT DTCS. Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-396630-S19862863392011050900000)
9. REPLACE ECM. Refer to «REMOVAL»(ref-396635-S35871318042011050900000)
10. GO TO VC OUTPUT CIRCUIT. Refer to «VC Output Circuit»(ref-396633-S16089907602011050900000)

See also:
• ON-VEHICLE INSPECTION - Step 2
• ON-VEHICLE INSPECTION
• ON-VEHICLE INSPECTION - Step 9
• REMOVAL
• REMOVAL
• INSPECTION
• INSPECTION - Step 2