Engine (3UZ-FE) - Diagnostics: Other Lexus GS III

REGISTRATION

Note. The Vehicle Identification Number (VIN) must be input into the replacement ECM.

HINT

The VIN is in the form of a 17- digit alphanumeric vehicle identification number. A hand-held tester is required to resister the VIN.

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1. DESCRIPTION This registration procedure consists of three parts, Input Instructions, Read VIN and Write VIN. Input Instructions: Explains the general VIN input instructions using a hand-held tester. Read VIN: Explains the VIN reading process in a flowchart. This process allows the VIN stored in the ECM to be read, in order to confirm that the two VINs, provided with the vehicle and stored in the vehicle's ECM, are the same. Write VIN: Explains the VIN writing process in a flowchart. This process allows the VIN to be input into the ECM. If the ECM is changed, or the VIN and VIN do not match, the VIN can be registered, or overwritten in the ECM by following this procedure.
2. INPUT INSTRUCTIONS Hand-held tester The arrow buttons (UP, DOWN, RIGHT and LEFT) and numerical buttons (0 to 9) are used, in order to input the VIN. Cursor Operation To move the cursor around the tester screen, press the RIGHT and LEFT buttons. Alphabetical Character Input Press the UP and DOWN buttons to select the desired alphabetical character. After selection, the cursor should move. Numeric Character Input Press the numerical button corresponding to the number that you want to input. After input, the cursor should move. HINT: Numerical characters can be selected by using the UP and DOWN buttons. Correction When correcting the input character(s), put the cursor onto the character using the RIGHT or LEFT buttons. Select or input the correct character using the UP/DOWN buttons, or the numerical buttons. Finishing Input Operation Make sure that the input VIN matches the vehicle VIN after input. Press the ENTER button on the tester.
3. READ VIN (Vehicle Identification Number) Read VIN using a hand-held tester. READ
4. WRITE VIN Write VIN using the hand-held tester. Write

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1. PURPOSE OF THE READINESS TESTS The On-Board Diagnostic (OBD II) system is designed to monitor the performance of emission-related components and report any detected abnormalities in the form of Diagnostic Trouble Codes (DTCs). Since the various components need to be monitored during different driving conditions, the OBD II system is designed to run separate monitoring programs called Readiness Monitors. Many state Inspection and Maintenance (I/M) programs require that vehicles complete their Readiness Monitors prior to beginning an emission test. The current status of the Readiness Monitors can be seen by using the hand-held tester with version 9.0 software (or newer), or a generic OBD II scan tool. To view the Readiness Monitor status using the hand-held tester, select "Monitor Status" from the Enhanced OBD II menu. A status of "complete" indicates that the necessary conditions have been met to run the performance tests for the related Readiness Monitor. The Readiness Monitor will be reset to "incomplete" if: ECM has lost power (battery or fuse). DTCs have been cleared. The conditions for running the Readiness Monitor have not been met. In the event that any Readiness Monitor shows "incomplete," follow the appropriate «READINESS MONITOR DRIVE PATTERN»(ref-229176-S20592704582006042000000) to activate the monitor and change the readiness status to "complete." CAUTION: Strictly observe the posted speed limits, traffic laws, and road conditions when performing these drive patterns. NOTE: These drive patterns represent the fastest method to satisfy all necessary conditions which allow the specific readiness monitor to complete. In the event that the drive pattern must be interrupted (possibly due to traffic conditions or other factors) the drive pattern can be resumed, and in most cases, the readiness monitor will still set to "complete". To ensure rapid completion of readiness monitors, avoid sudden changes in vehicle load and speed (driving up and down hills and/or sudden acceleration).
2. CATALYST MONITOR (O2S TYPE) Preconditions The monitor will not run unless: MIL is OFF. Engine Coolant Temperature (ECT) is 75°C (167°F) or greater. Intake Air Temperature (IAT) is -10°C (14°F) or greater. NOTE: The readiness test can be completed in cold ambient conditions (less than -10°C/14°F), if the drive pattern is repeated a second time after cycling the ignition off. Drive Pattern Connect the OBD II scan tool to the DLC3 to check monitor status and preconditions. Drive the vehicle at 40 to 55 mph (64 to 88 km/h) for approximately 3 minutes. NOTE: Drive with smooth throttle operation and avoid sudden acceleration. If IAT is less than 10°C (50°F) when engine was started, drive the vehicle at 40 to 55 mph (64 to 88 km/h) for additional 4 minutes. Drive the vehicle at 35 to 45 mph (56 to 72 km/h) for approximately 7 minutes. NOTE: Drive with smooth throttle operation and avoid sudden deceleration as much as possible with the throttle fully closed. If readiness status does not switch to complete, make sure that the preconditions are met and the ignition switch is turned OFF and then repeat steps 2 and 3 . Release pressure in the fuel tank by removing and then reinstalling the fuel tank cap. Start the engine and immediately begin driving as directed.
3. EVAP MONITOR (VACUUM PRESSURE MONITOR) NOTE: A cold soak must be performed prior to conducting the drive pattern to complete the Internal Pressure Readiness Monitor. Cold Soak Preconditions The monitor will not run unless: MIL is OFF Fuel level is approximately 1/2 to 3/4 Altitude is 7,800 feet (2,400 m) or less Cold Soak Procedure Let the vehicle cold soak for 8 hours or until the difference between IAT and ECT becomes less than 7°C(13°F) HINT: Examples: Scenario 1 ECT = 24°C(75°F) IAT = 16°C(60°F) Difference between ECT and IAT is 8°C (15°F) --> The monitor will not run because difference between ECT and IAT is greater than 7°C (13°F) Scenario 2 ECT = 21°C(70°F) IAT = 20°C(68°F) Difference between ECT and IAT is 1 °C (2°F) --> The monitor will run because difference between ECT and IAT is less than 7°C (13°F)
4. EVAP MONITOR (VACUUM PRESSURE MONITOR) (CONTINUED) Preconditions The monitor will not run unless: MIL is OFF Fuel level is approximately 1/2 to 3/4 Altitude is 7,800 feet (2,400 m) or less Engine Coolant Temperature (ECT) is between 4.4°C and 35°C (40°F and 95°F) Intake Air Temperature (IAT) is between 4.4°C and 35°C (40°F and 95°F) Cold Soak Procedure has been completed Before starting the engine, the difference between ECT and IAT must be less than 7°C (13°F) HINT: Examples: Scenario 1 ECT = 24°C(75°F) IAT = 16°C(60°F) Difference between ECT and IAT is 8°C (15°F) --> The monitor will not run because difference between ECT and IAT is higher than 7°C (13°F) Scenario 2 ECT = 21°C(70°F) IAT = 20°C(68°F) Difference between ECT and IAT is 1 °C (2°F) -->The monitor will run because difference between ECT and IAT is less than 7°C (13°F) The readiness test can be completed in cold ambient conditions (less than 40°F / 4.4°C) and/or at high altitudes (more than 7,800 feet / 2,400 m) if the drive pattern is repeated a second time after cycling the ignition off. Drive Pattern Connect the OBD II scan tool to DLC3 to check monitor status and preconditions (refer to (a)). Release pressure in fuel tank by removing the fuel tank cap and then reinstall it. Start the engine and allow it to idle until ECT becomes 75°C (167°F) or higher. Run the engine at 3,000 RPM for approximately 10 seconds. Allow the engine to idle with the A/C ON (to create slight load) for 15 to 50 minutes. NOTE: If the vehicle is not equipped with A/C, put a slight load on the engine by doing the following: Securely set the parking brake. Block the drive wheels with wheel chocks. Allow the vehicle to idle in drive for 15 to 50 minutes.
5. OXYGEN SENSOR MONITOR (FRONT AND REAR O2S SYSTEM) Preconditions The monitor will not run unless: MIL is OFF Drive Pattern Connect the OBD II scan tool to DLC3 to check monitor status and preconditions (refer to (a)). Start the engine and allow it to idle for 2 minutes or more. Drive the vehicle at 25 mph (40 km/h) or more for at least 50 seconds. Stop the vehicle and allow the engine to idle for 40 seconds or more. Perform steps 3 and 4 ten times. Check the status of the readiness monitor on the scan tool display. If readiness status did not switch to complete, ensure preconditions are met, turn the ignition off and then repeat steps 1 and 5 .
6. OXYGEN SENSOR HEATER MONITOR Preconditions The monitor will not run unless: MIL is OFF Drive Pattern Connect the OBD II scan tool to the DLC3 to check monitor status and preconditions (refer to a ). Start the engine and allow it to idle for 500 seconds or more. Drive the vehicle at 25 mph (40 km/h) or more for at least 2 minutes. Check the status of the readiness monitor on the scan tool display. If readiness status did not switch to complete, ensure the preconditions are met, turn the ignition off and then repeat steps 2 and 3 .

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Each ECM terminal's standard voltage is shown in the illustrations below. In the table, first follow the information under "Condition".

Look under "Symbols (Terminals No.)" for the terminals to be inspected.

The standard voltage between the terminals is shown under "STD Voltage".

Use the illustration above as a reference for the ECM terminals.

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MONITOR STRATEGY

MONITOR STRATEGY - DTC P0010

TYPICAL ENABLING CONDITIONS

TYPICAL ENABLING CONDITIONS - DTC P0010

TYPICAL MALFUNCTION THRESHOLDS

THRESHOLDS MALFUNCTION THRESHOLDS - DTC P0010

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE - DTC P0010

Scheme 274

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

THRESHOLDS MALFUNCTION THRESHOLDS

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

THRESHOLDS MALFUNCTION THRESHOLDS

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THRESHOLDS MALFUNCTION THRESHOLDS

Scheme 276

MONITOR RESULT (MODE 06 DATA)

Refer to PRE-CHECK for detailed information.

The test value and test limit information are described as shown in the following table. Check the monitor result and test values after performing the monitor drive pattern (see READINESS MONITOR DRIVE PATTERN ).

1. TID (Test Identification Data) is assigned to each emissions-related component.
2. TID (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
3. CID (Component Identification Data) is assigned to each test value.
4. Unit Conversion is used to calculate the test value indicated on generic OBDII scan tools.

TID $04: HO2S heater

HO2S HEATER DESCRIPTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Scheme 277

MONITOR STRATEGY

Scheme 278

THRESHOLDS MALFUNCTION

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

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MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Scheme 280

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

FAIL SAFE

If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed.

If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.

If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 281

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Scheme 282

If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed.

If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly. If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

MONITOR STRATEGY

Scheme 283

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Refer to PRE-CHECK for detailed information.

The test value and test limit information are described as shown in the following table. Check the monitor result and test values after performing the monitor drive pattern (see READINESS MONITOR DRIVE PATTERN ).

1. TID (Test Identification Data) is assigned to each emissions-related component.
2. TID (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
3. CID (Component Identification Data) is assigned to each test value.
4. Unit Conversion is used to calculate the test value indicated on generic OBDII scan tools.

TID $08: Thermostat

THERMOSTAT MOITOR RESULT DESCRIPTION

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING

Front HO2S voltage monitor

If the HO2S voltage is out of the standard value, the ECM interprets this as a malfunction.

TEST DATA DESCRIPTION

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1. Connect the hand-held tester to the DLC3.
2. Switch the hand-held tester from "normal mode" to "check mode" (See «PRE-CHECK»(ref-229176-S29341277952006042000000) ).
3. Start the engine and let the engine idle for 100 sec. or more.
4. Drive the vehicle at 40 km/h (25 mph) or more for 20 sec. or more.
5. Let the engine idle for 20 sec. or more.
6. Let the engine idle for 30 sec.

HINT

If a malfunction exists, the MIL will light up during step f .

Note. If the conditions in this test are not strictly followed, detection of the malfunction will not be possible. If you do not have a hand-held tester, turn the ignition switch OFF after performing steps c to f , then perform steps c to f again.

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Front HO2S slow slope monitor

If the HO2S sensor voltage is out of the standard value, the ECM interprets this as a malfunction.

FRONT HO2S SLOW SLOPE MONITOR

If the time required to change is out of the standard value, the ECM interprets this as a malfunction.

FRONT HO2S SLOW SLOPE MONITOR

Front HO2S frequency monitor (idling)

If the $38 is out of the standard value, the ECM interprets this as a malfunction.

FRONT HO2S FREQUENCY MONITOR

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

All

Scheme 286

P0136, P0156

Scheme 287

P0138, P0158

TYPICAL ENABLING CONDITIONS - DTC 0138, P0158

P0136, P0156

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P0138, P0158

Typical Malfunction Thresholds - DTC P0138, P0158

COMPONENT OPERATING RANGE

Rear HO2S voltage monitor

If the HO2S sensor voltage is out of the standard value, the ECM interprets this as a malfunction.

REAR HO2S VOLTAGE MONITOR

If the time required to change is out of the standard value, the ECM interprets this as a malfunction.

REAR HO2S MONITOR VOLTAGE

Rear HO2S slow response monitor

If the elapsed time is out of the standard value, the ECM interprets this as a malfunction.

REAR HO2S SLOW RESPONSE MONITOR

Rear HO2S element monitor

If all the values ($81, $84, $85 and $87) are out of the standard values, the ECM interprets this as a malfunction.

REAR H2OS ELEMENT MONITOR

TYPICAL MALFUNCTION THRESHOLDS

CONFIRMATION DRIVING PATTERN

1. Connect the hand-held tester to the DLC3.
2. Record DTC and the freeze frame data.
3. Use the hand-held tester to set the check mode (See «PRE-CHECK»(ref-229176-S29341277952006042000000) ).
4. Read the value on the misfire counter for each cylinder when idling. If the value is displayed on the misfire counter, skip the following procedure of confirmation driving.
5. Drive the vehicle several times with the engine speed, load and surrounding range shown as ENGINE SPD, CALC LOAD in the freeze frame data or MISFIRE RPM, MISFIRE LOAD in the DATA LIST. If you have no hand-held tester, turn the ignition switch OFF after the symptom is simulated once. Then repeat the simulation process again. HINT: In order to memorize the DTC of misfire, it is necessary to drive around MISFIRE RPM, MISFIRE LOAD in the DATA LIST for the following period of time. Take care not to turn the ignition switch OFF. Turning the ignition switch OFF switches the diagnosis system from check mode to normal mode, and all DTCs, etc., are erased. ENGINE SPEED - TIME REFRAME Engine Speed Time Idling 3 minutes 30 seconds or more 1,000 RPM 3 minutes or more 2,000 RPM 1 minute 30 seconds or more 3,000 RPM 1 minute or more
6. Check if there is misfire, the DTC and the freeze frame data. Record the DTCs, freeze frame data and misfire counter data.
7. Turn the ignition switch OFF and wait for at least 5 seconds.

TYPICAL MALFUNCTION THRESHOLDS

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TYPICAL MALFUNCTION THRESHOLDS

Scheme 290

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Scheme 291

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Scheme 292

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

Refer to PRE-CHECK for detailed information.

The test value and test limit information are described as shown in TID $01: CATALYST DESCRIPTION . Check the monitor result and test values after performing the monitor drive pattern (see READINESS MONITOR DRIVE PATTERN ).

1. TID (Test Identification Data) is assigned to each emissions-related component.
2. TID (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
3. CID (Component Identification Data) is assigned to each test value.
4. Unit Conversion is used to calculate the test value indicated on generic OBD II scan tools.

TID $01: Catalyst - Using HO2S on sensor 1 and 2

TID $01: CATALYST DESCRIPTION

Scheme 293

1. Connect the hand-held tester to the DLC3, or connect the probe of the oscilloscope between terminals OXL1, OXL2, OXR1, OXR2 and E1 of the ECM connector.
2. Start the engine and warm it up with all the accessories switched OFF until engine coolant temperature becomes stable.
3. Race the engine at 2,500 - 3,000 RPM for approximately 3 min.
4. After confirming that the waveform of the heated oxygen sensor (bank 1, 2 sensor 1 (OXL1, OXR1)), oscillate around 0.5 V during feedback to the ECM, check the waveform of the heated oxygen sensor (bank 1, 2 sensor 2 (OXL2, OXR2)).

HINT

If there is a malfunction in the system, the waveform of the heated oxygen sensor (bank 1, 2 sensor 2 (OXL2, OXR2)) is almost the same as that of the heated oxygen sensor (bank 1, 2 sensor 1 (OXL1, OXR1)) on the left.

There are some cases where, even though a malfunction exists, the MIL may either light up or not light up.

Scheme 294

Refer to PRE-CHECK for detailed information.

The test value and test limit information are described as shown in the following table. Check the monitor result and test values after performing the monitor drive pattern (see READINESS MONITOR DRIVE PATTERN ).

1. TID (Test Identification Data) is assigned to each emissions-related component. TID (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
2. CID (Component Identification Data) is assigned to each test value.
3. Unit Conversion is used to calculate the test value indicated on generic OBD II scan tools.

TID $02: EVAP - Vacuum monitor

TID $02: EVAP - VACUUM MONITOR RESULT

Scheme 295

TYPICAL MALFUNCTION THRESHOLDS

Refer to PRE-CHECK for detailed information.

The test value and test limit information are described as shown in the following table. Check the monitor result and test values after performing the monitor drive pattern (see READINESS MONITOR DRIVE PATTERN ).

1. TID (Test Identification Data) is assigned to each emissions-related component.
2. TID (Test Limit Type): If TLT is 0, the component is malfunctioning when the test value is higher than the test limit. If TLT is 1, the component is malfunctioning when the test value is lower than the test limit.
3. CID (Component Identification Data) is assigned to each test value.
4. Unit Conversion is used to calculate the test value indicated on generic OBDII scan tools.

TID $02: EVAP - Vacuum monitor

TID $02: EVAP - VACUUM MONITOR RESULT

TYPICAL MALFUNCTION THRESHOLDS

Scheme 296

TYPICAL MALFUNCTION THRESHOLDS

HINT

If DTC P0560 appears, the ECM does not store another DTC.

Scheme 297

TYPICAL ENABLING CONDITIONS

Scheme 298

TYPICAL MALFUNCTION THRESHOLDS

Scheme 299

MONITOR STRATEGY

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

COMPONENT OPERATING RANGE

If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed.

If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly. If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 300

Scheme 301

Scheme 302

Scheme 303

If the ETCS has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed. If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.

If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 304

Scheme 305

TYPICAL MALFUNCTION THRESHOLDS

If the ETCS (Electronic Throttle Control System) has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed.

If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly.

If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 306

Scheme 307

TYPICAL MALFUNCTION THRESHOLDS CHART

COMPONENT OPERATING RANGE

Scheme 308

If the ETCS has a malfunction, the ECM cuts off current to the throttle control motor. The throttle control valve returns to a predetermined opening angle (approximately 16°) by the force of the return spring. The ECM then adjusts the engine output by controlling the fuel infection (intermittent fuel-cut) and ignition timing in accordance with the accelerator pedal opening angle to enable the vehicle to continue at a minimum speed. If the accelerator pedal is depressed firmly and slowly, the vehicle can be driven slowly. If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 309

TYPICAL ENABLING CONDITIONS

TYPICAL MALFUNCTION THRESHOLDS

COMPONENT OPERATING RANGE

The accelerator pedal position sensor has two (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between the two sensor circuits and switches to limp mode. In limp mode, the remaining circuit is used to calculate the accelerator pedal opening to allow the vehicle to continue driving.

If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal to be fully closed. In this case, the throttle valve will remain closed as if the engine is idling.

If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 310

Scheme 311

Scheme 312

COMPONENT OPERATING RANGE

The accelerator pedal position sensor has two (main and sub) sensor circuits. If a malfunction occurs in either of the sensor circuits, the ECM detects the abnormal signal voltage difference between the two sensor circuits and switches to limp mode. In limp mode, the remaining circuit is used to calculate the accelerator pedal opening to allow the vehicle to continue driving.

If both circuits malfunction, the ECM regards the opening angle of the accelerator pedal to be fully closed. In this case, the throttle valve will remain closed as if the engine is idling.

If a "pass" condition is detected and then the ignition switch is turned OFF, the fail-safe operation will stop and the system will return to normal condition.

Scheme 313

Scheme 314

TYPICAL MALFUNCTION THRESHOLDS