Engine Controls - Diagnostics: Pre-Check

1. 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 onboard computer illuminates the Malfunction Indicator Light (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 )

     If the malfunction does not reoccur in 3 consecutive trips, the MIL goes off automatically but the DTCs remain recorded in the ECM memory.

     Fig 1: Diagnosis System

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • To check DTCs, connect the hand-held tester or OBD II scan tool to the Data Link Connector 3 (DLC3) of 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 (See the instruction manual for the OBD II scan tool or the hand-held tester). The DTC includes SAE controlled codes and manufacturer controlled codes. SAE controlled codes must be set according to the SAE, while manufacturer controlled codes can be set by a manufacturer with certain restrictions (See the DTC chart on DIAGNOSTIC TROUBLE CODE CHART ).
     Fig 2: Identifying Special Tool

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

     The diagnosis system operates in the 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  3).

   • *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 determining 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 DTCs (P0171, P0172, P0174 and P0175) and misfire DTCs (P0300 to P0306).
   2. Fuel trim malfunction DTCs (P0171, P0172 P0174 and P0175).
   3. Misfire DTCs (P0300 to P0306).
2. 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

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 4: Tester Connection Condition Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   Connect the cable of the OBD II scan tool or the hand-held tester to the DLC3, turn the ignition switch ON and attempt to use the hand-held tester. 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 the communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself. Consult the Service Department listed in the tool's instruction manual.
3. Inspect battery voltage.

   Battery Voltage: 11 to 14 V 

   If voltage is below 11 V, recharge the battery before proceeding.

4. Check MIL.
   1. The MIL turns on when the ignition switch is turned ON and the engine is not running.

      HINT:

      If the MIL does not light up, troubleshoot the combination meter (See INSPECTION ).

   2. When the engine is started, the MIL should turn off. If the lamp remains on, the diagnosis system has detected a malfunction or abnormality in the system.

1. Check DTC
   1. Connect the OBD II scan tool or hand-held tester to the DLC3.
   2. Turn the ignition switch ON.
      Fig 5: Connecting OBD II Scan Tool Or Hand-Held Tester DLC3

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Use the OBD II scan tool or the hand-held tester to check 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 PRE-CHECK  to confirm the details of the DTCs.
   NOTE: When simulating a symptom with the OBD II scan tool (excluding hand-held tester) to check the 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 again, the MIL illuminates 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. Using OBD II scan tool or hand-held tester:

   Clear DTC

   1. Connect the OBD II scan tool or the hand-held tester to the DLC3.
   2. Turn the ignition switch ON.
   3. Erase DTCs and freeze frame data with the OBD II scan tool (complying with SAE J1978) or the hand-held tester.

      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.

   4. Without using OBD II scan tool or hand-held tester:

      Clear DTC

      1. Remove the EFI and ETCS fuse from the engine room J/B for more than 60 seconds, or disconnect the battery cable for more than 60 seconds.

         After disconnecting the battery terminal, perform the "INITIALIZE" procedure (See PRE-CHECK ).

HINT:

Hand-held tester only:

Check mode has a higher sensitivity to detect malfunctions and can detect malfunction that normal mode cannot detect. Check mode can also detect all the malfunctions that normal mode can detect.

1. Check mode procedure
   1. Make sure that the item below are true:
      • Battery positive voltage 11V 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: Identifying Hand Held Tester

      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.
   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.
   9. After checking the DTC, inspect the applicable circuit.
      Fig 7: Identifying Wave Form

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Using OBD II scan tool or hand-held tester:

   Clear DTC

   1. Connect the OBD II scan tool or hand-held tester to the DLC3.
   2. Turn the ignition switch ON.
   3. Erase DTCs and freeze frame data with the OBD II scan tool (complying with SAE J1978) or the hand-held tester.

      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.

   4. Without using OBD II scan tool or hand-held tester:

      Clear DTC

      1. Remove the EFI and ETCS fuses from the engine room J/B for more than 60 seconds, or disconnect the battery cable for more than 60 seconds.

         After disconnecting the battery terminal, perform the "INITIALIZE" procedure (See PRE-CHECK ).

3. FAIL-SAFE CHART 

   If any of the following codes is recorded, the ECM enters fail-safe mode.

   Fig 8: Identifying Fail-Safe Chart

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
4. 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 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  2)
   2. Set the check mode. (See Step  3)
   3. Perform a simulation test (See HOW TO PROCEED WITH TROUBLESHOOTING ).
   4. Check the connector and terminal (See PROCEDURE )
   5. Wiggle the harness and connector (See PROCEDURE ).
5. 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 problems. In many cases, by carrying out the basic engine check shown in the following flowchart, the location causing the problem can be found quickly and efficiently. Therefore, using this check is essential in the engine troubleshooting.

   1. Is battery positive voltage 11 V or more when engine is stopped? 
      1. NO: Charge or replace battery. 
      2. YES: Go to next step. 
   2. Is engine cranked? 
      1. NO: Proceed to  TROUBLE SHOOTING  , and continue to troubleshoot. 
      2. YES: Go to next step. 
   3. Does engine start? 
      1. NO: Go to Step   f . 
      2. YES: Go to next step. 
   4. Check air filter. 

      PREPARATION: 

      Remove the air filter.

      CHECK: 

      Visually check that the air filter is not dirty or excessive oily.

      1. NG: Repair or replace. 
      2. OK: Go to next step. 
   5. Check idle speed. 

      PREPARATION: 

      1. Warm up the engine to 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 OBD II scan tool or hand-held tester to the DLC3 on the vehicle.

      CHECK: 

      Use the CURRENT DATA to check the idle speed.

      OK: 

      Idle speed: 650 - 750 RPM 

      1. NG: Proceed to problem symptoms table on  PROBLEM SYMPTOMS TABLE  . 
      2. OK: Go to next step. 
   6. Check ignition timing. 

      PREPARATION: 

      1. Warm up engine to normal operating temperature.
      2. Switch off all the accessories.
      3. Switch off the A/C.
      4. Shift the transmission into the N position.
      5. Keep the engine speed at idle.
      6. Using SST, connect terminals TC and CG of the DLC3.

         SST 09843-18020

      7. Using a timing light, connect the tester to check wire.

         CHECK: 

         Check the ignition timing.

         OK: 

         Ignition timing: 10° BTDC at idle 

         Fig 9: Checking Ignition Timing

         Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. NG: Proceed to  IGNITION  , and continue to troubleshoot. 
   2. OK: Proceed to problem symptoms table on  PROBLEM SYMPTOMS TABLE  . 
6. Check fuel pressure. 

   PREPARATION: 

   1. Be sure that enough fuel is in the tank.
   2. Connect the hand-held tester to the DLC3.
   3. Turn the ignition switch ON and push hand-held tester main switch ON.
   4. Use the ACTIVE TEST mode to operate the fuel pump.
   5. If you have no hand-held tester, connect the positive (+) and negative (-) leads from the battery to the fuel pump connector (See FUEL PUMP ).
      Fig 10: Checking Fuel Pressure

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   CHECK: 

   Check that the pulsation damper screw rises up when the fuel pump operates.

   1. NG: Proceed to  FUEL PUMP  , and continue to troubleshoot. 
   2. OK: Go to next step. 
7. Check for spark. 

   PREPARATION: 

   1. Remove the ignition coil from the spark plug.
   2. Remove the spark plug.
   3. Install the spark plug to the ignition coil, and connect the ignition coil connector.
   4. Disconnect the injector connector.
   5. Be sure to ground the screw of the spark plug securely.

   CHECK: 

   Check if spark occurs while the engine is being cranked.

   Fig 11: Checking Spark

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   NOTE:

   • Do not crash the electrode gap.
   • To prevent excess fuel being injected from the injectors during this test, don't crank the engine for more than 5 - 10 seconds at a time.
   1. NG: Proceed to  IGNITION  , and continue to troubleshoot. 
   2. OK: Proceed to problem symptoms table on  PROBLEM SYMPTOMS TABLE  . 

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.

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.
6. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DATA LIST.
7. According to the display on tester, read the "DATA LIST".
   Fig 12: Identifying Data List (1 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   Fig 13: Identifying Data List (2 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Fig 15: Toyota/Lexus Part And System Name List

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

This table below shows the ECM monitoring status for the components listed in the top of the table when the DTCs on the left of the table are set.

Fig 16: List Of Disable A Monitor Display (1 Of 4)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 17: List Of Disable A Monitor Display (2 Of 4)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 18: List Of Disable A Monitor Display (3 Of 4)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Fig 19: List Of Disable A Monitor Display (4 Of 4)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. 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 scan tool. 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 it 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 scan tool 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.

2. 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 20: Test Data Value

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Select the desired O2S and press ENTER. The following screen will appear.
   4. Press HELP and simultaneously. More information will appear.
   5. 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.
        Fig 21: Test Data Value

        Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      • 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.

        O2S TEST RESULT Chart 

        Fig 22: Test Result Chart

        Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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 (See 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 Display Chart

      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.
      Fig 24: Scan Tool

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   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.

      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.