Engine Control System (Diagnostic Codes (P0505 - P1603)): Overview Lexus RX III рестайлинг

DESCRIPTION

The idle speed is controlled by the electronic throttle control system. The electronic throttle control system is comprised of: 1) one valve type throttle with motor body assembly; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects the opening angle of the throttle valve; 4) the accelerator pedal position sensor, which detects the accelerator pedal position; 5) the ECM, which controls the electronic throttle control system. Based on the target idling speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

MONITOR DESCRIPTION

The ECM monitors the idling speed and idling air flow volume to conduct idle speed control. The ECM determines that the idle speed control system is malfunctioning if either of the following conditions are met

1. The difference between the target engine idling speed and actual engine idling speed exceeds the threshold and the idle speed control flow rate learned value is stuck at the upper or lower limit for 5 seconds or more.
2. After driving at a vehicle speed of 6.25 mph (10 km/h) or more, the difference between the target and actual engine idling speed exceeds the threshold 5 times or more during a driving cycle, and then the system determines that the idle speed control flow rate learned value is stuck at the upper or lower limit, or that the idle speed control flow rate learned value has been changed by an amount that exceeds the threshold.

Scheme 200

The idle speed is controlled by the electronic throttle control system. The electronic throttle control system is comprised of: 1) one valve type throttle with motor body assembly; 2) the throttle actuator, which operates the throttle valve; 3) the throttle position sensor, which detects the opening angle of the throttle valve; 4) the accelerator pedal position sensor, which detects the accelerator pedal position; 5) the ECM, which controls the electronic throttle control system. Based on the target idling speed, the ECM controls the throttle actuator to provide the proper throttle valve opening angle.

The ECM monitors the idling speed and idling air flow volume to conduct idle speed control. The ECM determines that the idle speed control system is malfunctioning if either of the following conditions are met

1. The difference between the target engine idling speed and actual engine idling speed exceeds the threshold and the idle speed control flow rate learned value is stuck at the upper or lower limit for 5 seconds or more.
2. After driving at a vehicle speed of 6.25 mph (10 km/h) or more, the difference between the target and actual engine idling speed exceeds the threshold 5 times or more during a driving cycle, and then the system determines that the idle speed control flow rate learned value is stuck at the upper or lower limit, or that the idle speed control flow rate learned value has been changed by an amount that exceeds the threshold.

This monitor will run when the engine is started at -10 to 50°C (14 to 122°F) of the engine coolant temperature. The DTC will be set after the engine has been idling 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 at a temperature lower than 50°C (122°F) of the engine coolant temperature, the ECM measures the accumulated mass air flow when the engine is idling. If it does not reach the criteria within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is set when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The electronic throttle control system controls the idle speed. The electronic throttle control system 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 negative battery terminal is disconnected during inspection or repairs, the idle speed control learned values are cleared. idle speed control learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the idle speed control learned values are cleared.

Scheme 201

This monitor will run when the engine is started at -10 to 50°C (14 to 122°F) of the engine coolant temperature. The DTC will be set after the engine has been idling 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 at a temperature lower than 50°C (122°F) of the engine coolant temperature, the ECM measures the accumulated mass air flow when the engine is idling. If it does not reach the criteria within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is set when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

The electronic throttle control system controls the idle speed. The electronic throttle control system 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 negative battery terminal is disconnected during inspection or repairs, the idle speed control learned values are cleared. idle speed control learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the idle speed control learned values are cleared.

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 is 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 less than 50°C (122°F), the ECM checks the ignition timing during engine idling. If the ignition timing advances beyond the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

Note. When the negative battery terminal is disconnected during inspection or repairs, the idle speed control learned values are cleared. idle speed control learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the idle speed control learned values are cleared.

HINT

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

Scheme 202

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 is 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 less than 50°C (122°F), the ECM checks the ignition timing during engine idling. If the ignition timing advances beyond the specified level within 10 seconds, the ECM interprets this as a malfunction. The MIL is illuminated and a DTC is stored when the malfunction is detected in consecutive driving cycles (2 trip detection logic).

Note. When the negative battery terminal is disconnected during inspection or repairs, the idle speed control learned values are cleared. idle speed control learning is performed when the engine has been warmed up and idled for 5 minutes because this DTC cannot be set after the idle speed control learned values are cleared.

HINT

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

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 stored ECM data is cleared and the ECM determines that there is a malfunction in the power supply circuit. When the engine is next started, the ECM will illuminate the MIL and set the DTC.

HINT

If DTC P0560 is set, the ECM does not store other DTCs.

The ECM continuously monitors its internal memory status. This self-check ensures that the ECM is functioning properly. The ECM memory status 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 a DTC 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 standards, the ECM will illuminate the MIL and set the DTC immediately.

The ECM continuously monitors its internal processors (CPUs) and heated oxygen sensor transistors. This self-check ensures that the ECM functioning properly.

The ECM continuously monitors its internal processors (CPUs) and heated oxygen sensor transistors. This self-check ensures that the ECM 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 malfunction below is detected, the DTC is stored.

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

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

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

While the engine is being cranked, positive battery voltage is applied to terminal STA of the ECM.

If the ECM detects the starter (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 sets the DTC.

This monitor runs when the vehicle is driven at 12.43 mph (20 km/h) or more for over 20 seconds.

While the engine is being cranked, positive battery voltage is applied to terminal STA of the ECM.

If the ECM detects the starter (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 sets the DTC.

This monitor runs when the vehicle is driven at 12.43 mph (20 km/h) or more for over 20 seconds.

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

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

DTC P0630 is set when the VIN is not stored in the ECM or the input VIN is not accurate. Input the VIN with the Techstream.

DTC P0630 is set when the VIN is not stored in the ECM or the input VIN is not accurate. 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 is usually 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 set a DTC when the engine switch is turned on (IG).

The park/neutral position switch assembly detects the shift lever position and sends signals to the ECM.

These DTCs indicate a problem with the park/neutral position switch assembly and the wire harness in the park/neutral position switch assembly circuit.

The park/neutral position switch assembly detects the shift lever position and sends a signal to the ECM.

For security, the park/neutral position switch assembly detects the shift lever position so that the engine can be started only when the shift lever is in P or N.

The park/neutral position switch assembly sends a signal to the ECM according to the shift lever position (P, R, N, D, or S). The ECM determines that there is a problem with the switch or related parts if it receives more than 1 position signal simultaneously. The ECM will turn on the MIL and store the DTC.

The park/neutral position switch assembly detects the shift lever position and sends signals to the ECM.

*1: except U880F

*2: for U880F

These DTCs indicate a problem with the park/neutral position switch assembly and the wire harness in the park/neutral position switch assembly circuit.

The park/neutral position switch assembly detects the shift lever position and sends a signal to the ECM.

For security, the park/neutral position switch assembly detects the shift lever position so that the engine can be started only when the shift lever is in P or N.

The park/neutral position switch assembly sends a signal to the ECM according to the shift lever position (P, R, N, D, S*1 or M*2). The ECM determines that there is a problem with the switch or related parts if it receives more than 1 position signal simultaneously. The ECM will turn on the MIL and store the DTC.

*1: except U880F

*2: for U880F

The purpose of this circuit is to prevent the engine from stalling, while driving with the lock-up torque converter clutch on, when brakes are suddenly applied.

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. Then the ECM cancels the operation of the lock-up clutch while braking is in progress.

This DTC indicates that the stop light switch assembly remains on. When the stop light switch assembly remains on during "stop and go" driving, the ECM interprets this as a malfunction in the stop light switch assembly and the MIL comes on and the ECM stores the DTC. The vehicle must stop (less than 1.86 mph (3 km/h)) and go (18.65 mph (30 km/h) or more) 5 times during 2 driving cycles, in order to detect a malfunction.

P1603

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

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

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

P1605

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

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

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

Scheme 203

Scheme 204

1. Reference waveforms showing a normal cold engine start
2. Reference waveforms showing a normal warm engine start
3. Reference values when there is an air leak in the intake system during rough idling FREEZE FRAME DATA P1605 ROUGH IDLING Parameter -3 -2 -1 0 1 Unit Engine Speed 647 649 586 378 182 RPM Calculate Load 26.2 26.2 29.1 42.6 58.6 % Vehicle Load 11.7 11.7 12.1 48.7 61.2 % MAF 2.87 2.87 2.87 6.23 3.04 gm/sec Atmosphere Pressure -0 -0 -0 -0 -0 kPa Coolant Temp 187 187 187 187 187 F Intake Air 109 109 109 109 109 F Battery Voltage 13.515 13.515 13.264 12.892 12.792 V Throttle Sensor Volt % 14.5 14.5 14.5 16.8 17.2 % Throttl Sensor #2 Volt % 46.2 46.2 46.2 48.4 49.2 % Throttle Sensor Position 0.0 0.0 0.0 0.0 0.0 % Throttle Motor DUTY 14.5 14.5 14.5 17.2 17.2 % Injector (Port) 2159 2161 2148 2190 2190 μs Injection Volume (Cylinder 1) 0.093 0.093 0.093 0.095 0.095 ml Fuel Pump Duty 58.6 58.6 58.6 58.6 58.6 % EVAP (Purge) VSV 13.3 13.3 13.3 13.3 13.3 % Evap Purge Flow 2.9 2.9 2.9 3.2 3.2 % Purge Density Learn Value 0.891 0.891 0.891 0.891 0.891 EVAP System Vent Valve OFF OFF OFF OFF OFF EVAP purge VSV OFF OFF OFF OFF OFF Purge Cut VSV Duty 8.5 8.5 8.5 8.5 8.5 % Target Air-Fuel Ratio 0.998 0.998 0.998 0.998 0.998 AF Lambda B1S1 0.999 0.997 1.001 1.038 1.118 AF Lambda B2S1 0.997 0.994 0.999 1.036 1.112 AFS Voltage B1S1 3.258 3.242 3.284 3.521 3.715 V AFS Voltage B2S1 3.251 3.306 3.324 3.497 3.689 V O2S B1S2 0.740 0.740 0.740 0.740 0.740 V O2S B2S2 0.760 0.760 0.760 0.760 0.760 V Short FT #1 -1.563 -1.563 -1.563 -1.563 -1.563 % Long FT #1 6.250 6.250 6.250 6.250 6.250 % Total FT #1 0.054 0.054 0.054 0.054 0.054 Sort FT #2 -0.782 -0.782 -0.782 -0.782 -0.782 % Long FT #2 7.031 7.031 7.031 7.031 7.031 % Total FT #2 0.062 0.062 0.062 0.062 0.062 Fuel System Status #1 CL CL CL CL CL Fuel System Status #2 CL CL CL CL CL IGN Advance 22.0 22.0 22.5 23.5 23.5 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

See also:
• ON-VEHICLE INSPECTION [03/2012 - ]
• ON-VEHICLE INSPECTION [03/2012 - ]
• ON-VEHICLE INSPECTION [03/2012 - ] - Step 2