Engine Controls - Diagnostics: Pre-Check

DIAGNOSIS SYSTEM
Description
- When troubleshooting On-Board Diagnostic (OBD II) vehicles, the vehicle must be connected to the OBD II scan tool (in compliance with SAE J1978) or the hand-held tester. Various data output from the vehicle's ECM can then be read.
- OBD II regulations require that the vehicle's on-board computer illuminates the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in: 1) the emission control system/components, or 2) the powertrain control components (which affect vehicle emissions), or 3) the computer. In addition, the applicable Diagnostic Trouble Codes (DTCs) prescribed by SAE J2012 are recorded in the ECM memory (see DIAGNOSTIC TROUBLE CODE CHART ).
  
  Fig 1: Identifying Malfunction Indicator Lamp
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
If the malfunction does not reoccur in 3 consecutive trips, the MIL turns off automatically but the DTCs remain recorded in the ECM memory.
- To check the DTC, connect the hand-held tester or OBD II scan tool to the Data Link Connector 3 (DLC3) on the vehicle. The hand-held tester or OBD II scan tool also enables you to erase the DTC and check the freeze frame data and various forms of engine data (for operating instructions, see the OBD II scan tool's instruction book). The DTC includes SAE controlled codes and manufacturer controlled codes. SAE controlled codes must be set as prescribed by the SAE, while manufacturer controlled codes can be set freely by a manufacturer within the prescribed limits (see DIAGNOSTIC TROUBLE CODE CHART ).
- The diagnosis system operates in "normal mode" during normal vehicle use. In "normal mode", 2 trip detection logic* is used to ensure accurate detection of malfunctions. A "check mode" is also available to technicians as an option. In "check mode", 1 trip detection logic is used for simulating malfunction symptoms and increasing the system's ability to detect malfunctions, including intermittent malfunctions (hand-held tester only) (see step 5).
  
  Fig 2: Connecting Hand Held Tester To DLC3 Connector
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- *2 trip detection logic:
  When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip). If the ignition switch is turned OFF and then ON again, and the same malfunction is detected again, the MIL will illuminate (2nd trip).
- Freeze frame data:
  The freeze frame data records the engine conditions (fuel system, calculated load, engine coolant temperature, fuel trim, engine speed, vehicle speed, etc.) when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.
Priorities for troubleshooting:

When multiple DTCs occur, find out the order in which the DTCs should be inspected by checking the component's DTC chart. If no instructions are written in the DTC chart, check DTCs in the following order of priority:
1. DTCs other than fuel trim malfunction (DTC P0171, P0172) and misfire (DTC P0300 - P0304).
2. Fuel trim malfunction (DTC P0171, P0172).
3. Misfire (DTC P0300 - P0304).

CHECK DLC3

The vehicle's ECM uses the ISO 9141-2 for communication protocol. The terminal arrangement of the DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

Fig 3: Identifying DLC3 Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Condition	Specified Condition
7 (Bus + line) - 5 (Signal ground)	During communication	Pulse generation
4 (Chassis ground) - Body ground	Constant	Below 1 Ω
5 (Signal ground) - Body ground	Constant	Below 1 Ω
16 (B+) - Body ground	Constant	9 to 14 V

HINT:

Connect the cable of the hand-held tester or the OBD II scan tool to the DLC3, turn the ignition switch ON and attempt to use the hand-held tester or the OBD II scan tool. If the screen displays UNABLE TO CONNECT TO VEHICLE, a problem exists in the vehicle side or the tester side.

If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
If communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.

INSPECT BATTERY VOLTAGE
Battery voltage: 11 to 14 V

If the voltage is below 11 V, recharge the battery before proceeding.
CHECK MIL
1. The MIL turns on when the ignition switch is turned ON and the engine is not running.
  HINT:
  
  If the MIL is not illuminated, troubleshoot the MIL circuit (see MIL CIRCUIT MALFUNCTION ).
2. When the engine is started, the MIL should turn off. If the lamp remains on, it means that the diagnosis system has detected a malfunction or abnormality in the system.
DTC CHECK (Normal Mode)
NOTE:
- If there is no DTC in the normal mode, check the pending fault code using the Continuous Test Results function (Mode 7 for SAE J1979) on the OBD II scan tool or the hand-held tester.
- Hand-held tester only:
  When the diagnosis system is switched from the normal mode to the check mode, all the DTCs and freeze frame data recorded in the normal mode will be erased. So before switching modes, always check the DTCs and freeze frame data, and then write them down.
1. Checking DTCs using the hand-held tester or OBD II scan tool.
  1. Connect the hand-held tester or the OBD II scan tool to DLC3.
  2. Turn the ignition switch ON.
  3. Use the hand-held tester or the OBD II scan tool to check the DTCs and freeze frame data and then write them down.
    For the hand-held tester, enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES. For the OBD II scan tool, see its instruction manual.
  4. See DIAGNOSTIC TROUBLE CODE CHART to confirm the details of the DTCs.
    
    Fig 4: Connecting Hand-Held Tester To DLC3 Connector
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  NOTE:
  When simulating a symptom with the OBD II scan tool (excluding hand-held tester) to check for DTCs, use the normal mode. For DTCs subject to "2 trip detection logic", perform either of the following actions.
  - Turn the ignition switch OFF after the symptom is simulated once. Then repeat the simulation process again. When the problem has been simulated twice, the MIL lights up and the DTCs are recorded in the ECM.
  - Check the pending fault code using the Continuous Test Results function (Mode 7 for SAE J1979) on the OBD II scan tool.
2. Clearing the DTCs using the hand-held tester or the OBD II scan tool.
  1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
  2. Turn the ignition switch ON.
  3. Erase DTCs and freeze frame data using the hand-held tester or the OBD II scan tool (complying with SAE J1978).
    For the hand-held tester: 1) enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CLEAR CODES; and 2) press YES. For the OBD II scan tool, see its instruction manual.
3. Clearing the DTCs without using the hand-held tester or the OBD II scan tool.
  1. Remove the EFI1 fuse from the engine room J/B and ETCS fuse from the engine room R/B for more than 60 seconds. Or, disconnect the battery terminal for more than 60 seconds.
    After disconnecting the battery terminal, perform the "INITIALIZE" procedure (see PRE-CHECK in Automatic Transaxle Diagnostics article).
    
    Fig 5: Locating Engine Room J/B EFI1 Fuse And Engine Room R/B ETCS Fuse
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DTC CHECK (Check Mode)
HINT:

Hand-held tester only:

Check mode has a higher sensitivity to detect malfunctions and can detect malfunctions that normal mode cannot detect.

Check mode can also detect all the malfunctions that normal mode can detect.
1. Procedure for Check Mode using the hand-held tester.
  1. Make sure that the items below are true:
    - Battery positive voltage 11 V or more.
    - Throttle valve fully closed.
    - Transmission in the P or N position.
    - A/C switched OFF.
  2. Turn the ignition switch OFF.
  3. Connect the hand-held tester to the DLC3.
  4. Turn the ignition switch ON.
    
    Fig 6: Connecting Hand Held Tester To DLC3 Connector
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  5. Change the ECM to check mode with the hand-held tester. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / CHECK MODE. Make sure the MIL flashes as shown in the illustration.
    NOTE: All DTCs and freeze frame data recorded will be erased if: 1) the hand-held tester is used to change the ECM from normal mode to check mode or vice-versa; or 2) during check mode, the ignition switch is turned from ON to ACC or OFF.
    
    Fig 7: Identifying MIL Flashes
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. Start the engine. The MIL should turn off after the engine starts.
  7. Simulate the conditions of the malfunction described by the customer.
  8. After simulating the malfunction conditions, use the hand-held tester diagnosis selector to check the DTC, freeze frame data and other data.
    - After checking the DTC, inspect the applicable circuit.
2. Clearing the DTCs using the hand-held tester or the OBD II scan tool.
  1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
  2. Turn the ignition switch ON.
  3. Erase DTCs and freeze frame data with the hand-held tester or the OBD II scan tool (complying with SAE J1978)
    For the hand-held tester: 1) enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CLEAR CODES; and 2) press YES. For the OBD II scan tool, see its instruction manual.
3. Clearing the DTCs not using the hand-held tester or the OBD II scan tool.
  1. Remove the EFI1 fuse from the engine room J/B and ETCS fuse from the engine room R/B for more than 60 seconds. Or, disconnect the battery terminal for more than 60 seconds. After disconnecting the battery terminal, perform the "INITIALIZE" procedure (see PRE-CHECK in Automatic Transaxle Diagnostics article).
    
    Fig 8: Locating Engine Room J/B EFI1 Fuse And Engine Room R/B ETCS Fuse
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
FAIL-SAFE CHART
If any of the following codes are recorded, the ECM enters the fail-safe mode.

Fig 9: DTC Fail Safe Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
CHECK FOR INTERMITTENT PROBLEMS
Hand-held tester only:

Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect when the ECM is in check mode with the hand-held tester. In check mode, the ECM uses 1 trip detection logic, which has a higher sensitivity to malfunctions than normal mode (default), which uses 2 trip detection logic.
1. Clear the DTCs (see step 5).
2. Set the check mode (see step 6).
3. Perform a simulation test (see SYMPTOM SIMULATION under HOW TO PROCEED WITH TROUBLESHOOTING in INTRODUCTION article).
4. Check the connector and terminal (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE in INTRODUCTION article).
5. Wiggle the harness and connector (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE in INTRODUCTION article).
BASIC INSPECTION
When the malfunction is not confirmed in the DTC check, troubleshooting should be carried out in all the possible circuits considered as causes of the problem. In many cases, by carrying out the basic engine check shown in the following flow chart, the location causing the problem can be found quickly and efficiently. Therefore, using this check is essential in the engine troubleshooting.

Is battery positive voltage 11 V or more when engine stopped?
1. NO : Charge or replace battery.
2. YES : Go to next step.
Is engine cranked?
1. NO : Proceed to STARTERS article and continue to troubleshoot.
2. YES : Go to next step.
Does engine start?
1. NO : Go to step 6 .
2. YES : Go to next step.
Check air filter.
PREPARATION:

Remove the air filter.

CHECK:

Visually check if air filter is contaminated with dirty or oily.
1. NG : Repair or replace.
2. OK : Go to next step.
Check idle speed.
PREPARATION:
1. Warm up the engine to the normal operating temperature.
2. Switch off all the accessories.
3. Switch off the A/C.
4. Shift the transmission into the N position.
5. Connect the hand-held tester or OBD II scan tool to the DLC3 of the vehicle.
CHECK:

Use CURRENT DATA to check the idle speed.

OK:

Idle speed:

M/T: 650 to 750 RPM

A/T: 550 to 750 RPM
1. NG : Proceed to PROBLEM SYMPTOMS TABLE .
2. OK : Go to next step.
Check fuel pressure (see ON-VEHICLE INSPECTION ).
1. NG : Proceed to Check fuel pressure (see ON-VEHICLE INSPECTION and continue to troubleshoot.
2. OK : Go to next step.
Check for spark.
PREPARATION:
1. Disconnect the ignition coil.
2. Remove the spark plug.
3. Install the spark plug to the ignition coil assembly.
4. Disconnect the injector connector.
5. Ground the spark plug.
CHECK:

Check if spark occurs while the engine is being cranked.
NOTE:
- Do not crash the electrode gap.
- To prevent the injectors from injecting excess fuel during this test, do not crank the engine for more than 5 seconds at one time.
1. NG : Proceed to ON-VEHICLE INSPECTION in IGNITION article and continue to troubleshoot.
2. OK : Proceed to PROBLEM SYMPTOMS TABLE .
DATA LIST
HINT:

Using the hand-held tester DATA LIST allows switch, sensor, actuator and other item values to be read without removing any parts. Reading the DATA LIST early in troubleshooting is one way to shorten labor time.

NOTE: In the table below, the values listed under "Normal Condition" are reference values. Do not depend solely on the these reference values when deciding whether a part is faulty or not.
1. Warm up the engine.
2. Turn the ignition switch OFF.
3. Connect the hand-held tester or the OBD II scan tool to the DLC3.
4. Turn the ignition switch ON.
5. Push the "ON" button of the hand-held tester or the OBD II scan tool.
6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST.
7. According to the display on tester, read the "DATA LIST".
  
  Fig 10: Hand Held Tester Display Data List (1 Of 3)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fig 11: Hand Held Tester Display Data List (2 Of 3)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 12: Hand Held Tester Display Data List (3 Of 3)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
ACTIVE TEST
HINT:

Performing the hand-held tester ACTIVE TEST allows relay, VSV, actuator and other items to be operated without removing any parts. Performing the ACTIVE TEST early in troubleshooting is one way to shorten labor time. The DATA LIST can be displayed during the ACTIVE TEST.
1. Warm up the engine.
2. Turn the ignition switch OFF.
3. Connect the hand-held tester or the OBD II scan tool to the DLC3.
4. Turn the ignition switch ON.
5. Turn ON the hand-held tester or the OBD II scan tool.
6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST.
7. According to the display on tester, perform the ACTIVE TEST.
  
  Fig 13: Hand Held Tester Display Active Test
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
DEFINITION OF TERMS

Fig 14: Terms Definition Table
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TOYOTA/LEXUS PART AND SYSTEM NAME LIST

This reference list indicates the part names used in this manual along with their definitions.

TOYOTA/LEXUS PART AND SYSTEM NAME LIST

TOYOTA/LEXUS Name	Definition
Toyota HCAC system, Hydro-carbon Adsorptive Catalyst (HCAC) system, HC adsorptive three-way catalyst	HC adsorptive three-way catalytic converter
Variable valve timing sensor, VVT sensor	Camshaft position sensor
Variable valve timing system, VVT system	Camshaft timing control system
Camshaft timing oil control valve, Oil control valve, OCV, VVT, VSV	Camshaft timing oil control valve
Variable timing and lift, VVTL	Camshaft timing and lift control
Crankshaft position sensor "A"	Crankshaft position sensor
Engine speed sensor	Crankshaft position sensor
THA	Intake air temperature
Knock control module	Engine knock control module
Knock sensor	Engine knock sensor
Mass or volume air flow circuit	Mass air flow sensor circuit
Vacuum sensor	Manifold air pressure sensor
Internal control module, Control module, Engine control ECU, PCM	Power train control module
FC idle	Deceleration fuel cut
Idle air control valve	Idle speed control
CCV, Canister close valve VSV for canister control	Evaporative emissions canister vent valve
EVAP VSV, Vacuum switching valve assembly No. 1, EVAP VSV, Purge VSV	Evaporative emissions canister purge valve
Pressure switching valve, Bypass VSV	Evaporative emission pressure switching valve
Vapor pressure sensor, EVAP pressure sensor, Evaporative emission control system pressure sensor	Fuel tank pressure sensor
Charcoal canister	Evaporative emissions canister
ORVR system	On-board refueling vapor recovery system
Intake manifold runner control	Intake manifold tuning system
Intake manifold runner valve, IMRV, IACV (runner valve)	Intake manifold tuning valve
Intake control VSV	Intake manifold tuning solenoid valve
AFS	Air fuel ratio sensor
O2 sensor	Heater oxygen sensor
Oxygen sensor pumping current circuit	Oxygen sensor output signal
Oxygen sensor reference ground circuit	Oxygen sensor signal ground
Accel position sensor	Accelerator pedal position sensor
Throttle actuator control motor, Actuator control motor, Electronic throttle motor, Throttle control motor	Electronic throttle actuator
Electronic throttle control system, Throttle actuator control system	Electronic throttle control system
Throttle/pedal position sensor, Throttle/pedal position switch, Throttle position sensor/switch	Throttle position sensor
Turbo press sensor	Turbocharger pressure sensor
Turbo VSV	Turbocharger pressure control solenoid valve
P/S pressure switch	Power-steering pressure switch
VSV for ACM	Active control engine mount

List of Disable a Monitor
HINT:

This table indicates ECM monitoring status for the items in the upper columns if the DTCs in each line on the left are being set.

As for the "X" make, when the DTC on the left is stored detection of the DTC in the upper column is not performed.

Fig 15: Monitor Disabling Chart (1 Of 6)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 16: Monitor Disabling Chart (2 Of 6)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 17: Monitor Disabling Chart (3 Of 6)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 18: Monitor Disabling Chart (4 Of 6)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 19: Monitor Disabling Chart (5 Of 6)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 20: Monitor Disabling Chart (6 Of 6)
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

O2S TEST RESULT

INTRODUCTION
The O2S TEST RESULT refers to the results of the engine control module (ECM) when it monitors the oxygen sensor (O2S), and it can be read using the hand-held tester or the generic OBDII scantool. Based on this, you can find the O2S's conditions.

The ECM monitors the O2S in the various items. You can read the monitor result (TEST DATA) of each monitor item using the O2S TEST RESULT. However, the output value of the TEST DATA is the latest "snapshot" value that is taken after monitoring and therefore it is not dynamic.

In this repair manual, the description of the O2S TEST RESULT (for O2S related DTCs) are written in a table. This table consists of 5 items:
1. TEST ID (a code applied to each TEST DATA)
2. Description of TEST DATA
3. Conversion Factor (When Conversion Factor has a value written in the table, multiply the TEST DATA value appearing on the scantool by the Conversion Factor value. The result will be the required value.)
4. Unit
5. Standard Value
If the TEST DATA value appearing on the scan tool is out of the standard value, the O2S is malfunctioning. If it is within the standard value, the O2S is functioning normally. However, if the value is on the borderline of the standard value, the O2S may malfunction very soon.
HOW TO READ O2S TEST RESULT USING HAND-HELD TESTER
1. Connect the hand-held tester to the DLC3.
2. On the tester screen, select the following menus: DIAGNOSIS / CARB OBDII / O2S TEST RESULT. A list of the O2S equipped on the vehicle will be displayed.
  
  Fig 21: O2S Test Result Screen
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Select the desired O2S and press ENTER. The following screen will appear.

Example

The hand-held tester displays "17" as a value of the "TIME $81" (see the illustration on the left).
Find the Conversion Factor value of "TIME $81" in the O2S TEST RESULT chart below. 0.3906 is specified for $81 in this chart.
Multiply "17" in step (1) by 0.3906 (Conversion Factor) in the step (2).
17 x 0.3906 = 6.6 %
If the answer is within the standard value, the "TIME $81" can be confirmed to be normal.

Fig 22: Test Data Screen
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

O2S TEST RESULT Chart

O2S TEST RESULT CHART

TEST ID	Description of TEST DATA	Conversion Factor	Unit	Standard Value
$81	Percentage of monitoring time when the O2S voltage is less than 0.05 V	Multiply 0.3906	%	Within 60 %

CHECKING MONITOR STATUS
NOTE: The Monitor Status is not applicable to the heated oxygen sensor (HO2S). The HO2S status can be checked with O2S TEST RESULT.
1. INTRODUCTION
  The purpose of the monitor result (mode 6) is to allow access to the results for on-board diagnostic monitoring tests of specific components/systems that are not continuously monitored. Examples are catalyst, EVAP and thermostat.
  
  The monitor result allows the OBD scan tool to display the monitor status, test value and test limit. The monitor status indicates whether the component is functioning normally or not (PASS or FAIL). The test value is the value that was used to determine the monitor status. When the test value is inside the test limit, the ECM determines the component is functioning normally (PASS). If the test value is outside the test limit, the ECM determines the component is malfunctioning (FAIL).
  
  A problem in these components/systems can be found by comparing the test value and test limit. The monitor result information is included under "MONITOR RESULT" in the DTC sections.
2. PROCEDURE
NOTE: The monitor result and test value are cleared when the ignition switch is turned OFF.
1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch ON.
3. Clear the DTCs.
4. Run the vehicle in accordance with the applicable drive pattern described in READINESS MONITOR DRIVE PATTERN ).
5. Select from the tester menus: DIAGNOSIS, ENHANCED OBD II, MONITOR INFO and MONITOR RESULT. The monitor result appears after the component name.
  INCMP: The component has not been monitored yet.
  
  PASS: The component is functioning normally.
  
  FAIL: The component is malfunctioning.
6. Confirm that the component is set to either PASS or FAIL.
  
  Fig 23: Monitor Result Screen
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
7. Select the component (Label) and press ENTER.
  The accuracy test value appears when the monitor result is either PASS or FAIL.
  
  VAL The test value
  
  LMT: The test limit
  
  TLT: The test limit type. Either 0 or 1 is displayed.
8. 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.
9. Compare the test value with the test limit. The test value is usually significantly higher or lower than the test limit. If the test value is on the borderline of the test limit, there is a potential malfunction in the component.
  
  Fig 24: Thermostat Malfunction Screen
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

The monitor result might on rare occasions be PASS even if the MIL is illuminated. This indicates the system malfunctioned on a previous driving cycle. This might be caused by an intermittent problem.