Engine - Diagnostics: Pre-Check

1. Description

   When troubleshooting OBD II (On-Board Diagnostics) vehicles, a hand-held tester or OBD II scan tool (complying with SEA J1987) must be connected to the DLC3 (Data Link Connector 3) of the vehicle. Various data in the vehicle's ECM (Engine Control Module) can be then read. OBD II regulations require that the vehicle's on board computer illuminates the MIL (Malfunction Indicator Lamp) on the instrument panel when the computer detects a malfunction in:

   Fig 1: Identifying Malfunction Indicator Lamp

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   • The emission control systems and components
   • The power train control components (which affect vehicle emissions)
   • The computer itself

   In addition, the applicable DTCs (Diagnostic Trouble Codes) prescribed by SEA J2012 are recorded in 3 consecutive trips, the MIL turns off automatically but the DTCs remain recorded in the ECM (Engine Control Module) memory.

   To check the DTCs, connect a hand-held tester or OBD II scan tool to the DLC3. The tester and scan tool display DTCs, freeze frame data, and a variety of engine data. The DTCs and freeze frame data can be erased with the tester and scan tool.

   Fig 2: Connecting Hand-Held Tester To DLC3

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2. Normal mode and check mode

   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. Check mode is also available as an option for technicians. In check mode, 1 trip detection logic is used for simulating malfunction symptoms and increasing the system's ability to detect malfunctions, including intermittent problems (hand-held tester only).

3. 2 tip detection logic

   When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory (1st trip).If the same malfunction is detected during the next sequent drive cycle, the MIL is illuminated (2nd trip).

4. Freeze frame data

   The freeze frame data record the engine conditions (fuel system, calculated engine load, engine coolant temperature, fuel trim, engine speed, vehicle speed, etc) when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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.

5. DLC3 (Data Link Connector 3)

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

   Fig 3: Identifying Data Link Connector 3 Terminals

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   DLC3 TERMINAL REFERENCE
   
   

   Symbol	Terminal No.	Name	Reference Terminal	Result	Condition
   SIL	7	Bus "+" line	5-Signal ground	Pulse generation	During transmission
   CG	4	Chassis ground	Body ground	1 Ω or less	Always
   SG	5	Signal ground	Body ground	1 Ω or less	Always
   BAT	16	Battery positive	Body ground	9 to 14 V	Always

   NOTE: The DLC3 is the interface prepared for reading various data from the vehicle's ECM. After connecting the cable of a hand-held tester or OBD II scan tool, turn the ignition switch to ON and turn the tester or scan tool ON.

   If a communication failure message is displayed on the tester or scan tool screen (on the tester: UNABLE TO CONNECT TO VEHICLE), a problem exists in either the vehicle or tester. In order to identify the location of the problem, connect the tester to another vehicle.

   • If communication is normal: Inspect the DLC3 on the original vehicle.
   • If communication is impossible: The problem is probably with the tester itself. Consult the Service Department listed in the instruction manual.
6. Battery voltage

   Battery voltage: 11 to 14 V 

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

7. MIL (Malfunction Indicator Lamp)
   1. The MIL illuminates when the ignition switch is turned to ON and the engine is not running.
      NOTE: If the MIL does not illuminate, check the MIL circuit (see CIRCUIT DESCRIPTION ).
   2. The MIL should turn off when the engine is started. If the MIL remains on, the diagnosis system has detected a malfunction or abnormality in the system.

1. Check DTCs (using a hand-held tester or OBD II scan tool)
   1. Connect a hand-held tester or OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the tester or scan tool ON.
   4. For the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
      Fig 4: Connecting Hand-Held Tester Or OBD II Scan Tool To DLC3

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   5. Check the DTC(s) and freeze frame data, and then write them down.
   6. See DIAGNOSTIC TROUBLE CODE CHART  to check the details of the DTC(s).
   NOTE: When simulating a symptom with an OBD II scan tool to check DTCs in the DIAGNOSTIC TRO7UBLE CODE CHART, subject to 2 trip detection logic, conduct either of the following operations.
   • Check pending DTCs using the Continuous Test Result function mode 07 for SAE J1979).
   • Simulate the symptom again after turning the ignition switch to OFF upon finishing the first symptom simulation, so that the MIL is illuminated and the DTC(s) is stored in the ECM.
2. Clear DTCs (using a hand-held tester or OBD II scan tool)
   1. Connect a hand-held tester or OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the tester or scan tool ON.
   4. For the tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CLEAR CODES.
   5. Press the YES button.
3. Clear DTCs (without using a hand-held tester or OBD II scan tool)
   1. Perform either one of the following operations.
      • Disconnect the negative battery cable for more than 1 minute.
      • Remove the EFI fuse from the Relay Block (R/B) located inside the engine compartment for more than 1 minute.

Compared to normal mode, check mode is more sensitive to malfunctions. Therefore, check mode can detect the malfunctions that cannot be detected by normal mode.

1. Procedure for check mode (using a hand-held tester)
   1. Make sure that the vehicle is in the following condition:
      • Battery voltage 11 V or more.
      • Throttle valve fully closed.
      • Transmission in the P or N position (A/T).
      • A/C switched OFF.
   2. Turn the ignition switch to OFF.
   3. Connect a hand-held tester to the DLC3.
      Fig 5: Connecting Hand-Held Tester To DLC3

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   4. Turn the ignition switch to ON.
   5. Turn the tester ON.
   6. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / CHECK MODE.
   7. Switch the ECM from normal mode to check mode. (Make sure the MIL flashes as shown in the illustration.)
   8. Start the engine. (Make sure the MIL turns off.)
   9. Simulate the conditions of the malfunction described by the customer.
   10. Check DTCs and freeze frame data using the tester.
   Fig 6: MIL Flashes Graph In Check Mode

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

Inspect the vehicle's ECM using check mode. Intermittent problems are easier to detect with the hand-held tester when the ECM is in check mode. In check mode, the ECM uses 1 trip detection logic, which is more sensitive to malfunctions than normal mode (default) that uses 2trip detection logic.

1. Clear DTCs (see step 2).
2. Switch the ECM from normal mode to check mode using a hand-held tester.
3. Perform a simulation test (see HOW TO PROCEED WITH TROUBLESHOOTING ).
4. Check and wiggle the harness(es), the connector(s) and terminal(s) (see HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE ).

When a malfunction is not confirmed by the DTC check, troubleshooting should be carried out in all circuits considered to be possible causes of the problem. In many cases, by carrying out the basic engine check shown in the following flowchart, the location of the problem can be found quickly and efficiently. Therefore, using this check is essential when engine troubleshooting.

1. Is battery positive voltage 11 V or more when engine stopped? 
   1. NO: change or replace battery. 
   2. YES: Go To Next Step 
2. Is engine cranked? 
   1. NO: Proceed to page ST-16 and continue to troubleshoot. 
   2. YES: Go To Next Step 
3. Does engine start? 
   1. NO: Go to   6 . 
   2. YES: Go To Next Step 
4. Check air filter. 

   PREPARATION:

   Remove the air filter.

   OK:

   Visual check that the air filter is not excessively dirty or oily.

   1. NG: Replace air filter. 
   2. OK : Go to next step 
5. Check idling speed. 

   PREPARATION:

   1. Warm up the engine to the normal operating temperature.
   2. Switch off all the accessories.
   3. Switch off 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:

   Check the idling speed.

   OK:

   1. Idling speed: 
   2. M/T: 600 to 700 RPM 
   3. A/T: 650 to 750 RPM 
   1. NG: Proceed to  PROBLEM SYMPTOMS TABLE  . 
   2. OK : Go to next step 
6. Check fuel pressure. 

   PREPARATION:

   1. Be sure that there is sufficient fuel in the tank.
   2. Connect the hand-held tester to the DLC3.
   3. Turn the ignition switch to ON and turn the hand-held tester ON.
   4. Use ACTIVE TEST mode to operate the fuel pump.
   5. Please refer to the hand-held tester operator's manual for further details.
   6. If you have no hand-held tester, connect the positive (+) and negative (-) battery leads to the fuel pump connector (see FUEL PUMP )
      Fig 7: Preparation For Fuel Pressure Check

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   CHECK:

   Check for the fuel pressure in the fuel inlet hose when it is pinched by hand.

   NOTE: You will hear the fuel flowing sound while the fuel pump is in operation.
   1. NG: Proceed to page SF-7 and continue to troubleshoot. 
   2. OK : Go to next step 
7. 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.
      Fig 8: Preparation For Spark Check

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   CHECK:

   Check if spark occurs while the engine is being cranked.

   NOTE:

   • Do not change 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 a time.
   1. NG: Proceed to page IG-1 and continue to troubleshoot. 
   2. OK : Go to next step 

   Proceed to  PROBLEM SYMPTOMS TABLE  . 

1. Warm up the engine.
2. Turn the ignition switch to OFF.
3. Connect a hand-held tester to the DLC3.
4. Turn the ignition switch to ON.
5. Turn the tester ON.
6. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DATA LIST.
7. Check the values by referring to the table below.

Fig 9: Data List Chart (1 Of 3)

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Fig 10: Data List Chart (2 Of 3)

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Fig 11: Data List Chart (3 Of 3)

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DATA LIST can be displayed during ACTIVE Tests.

1. Connect the hand-held tester to the DLC3.
2. Turn the ignition switch to ON.
3. Turn the tester ON.
4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / ACTIVE TEST.
5. Perform the ACTIVE TEST by referring to the table below.

Fig 12: Active Test Chart

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

1. Description of O2S TEST RESULT.

   The O2S Test Result is a part of the monitoring for Heated Oxygen (HO2) sensor malfunctions. The various states (Test Items) of the HO2 sensor are monitored by the ECM. The Test Item values (Test Value) can be read using a hand-held tester or OBD II scan tool.

   A Test Value is the latest snapshot data after the vehicle is driven to run the monitor. Therefore, the Test Value is not dynamic data.

   If a Test Value is outside the standard range, this indicates that the HO2 sensor is malfunctioning. If a Test Value is on the borderline of the standard level, any malfunctions may be concealed in the HO2 sensor.

   Test Values are cleared when the ignition switch is turned to OFF.

   Example

   O2S TEST RESULT
   
   

   Test ID	Test Item	Description	Unit Conversion	Unit	Standard
   $81	Time $81	Percentage of time when HO2S voltage was below 0.05 V in HO2S monitoring time	Multiply by 0.3906	%	Within 60 %

   • Test ID: Code applied to each Test Item
   • Test Item: State to be monitored in the test
   • Description: Monitoring method
   • Unit Conversion: Conversion factor used to calculated the Test Value dis0played on a hand-held tester
   • Unit: Unit applied to a Test Value
   • Standard: The standard range or level used to judge whether or not the HO2 sensor is normal
   NOTE:

   • Specifics of each Test Item, Description, Unit Conversion and Standard are described in the paragraph titled "O2S TEST RESULT" in each DTC section relating the HO2 sensor, such as P0139, P0133 and P0136.
   • The O2S Test Result is not applicable to the A/F (Air-Fuel Ratio) sensor and the HO2 sensor heater. The Monitor Result is used for these components tests. For more information about the tests, refer to  13 .
2. Procedure of O2S TEST RESULT.
   CAUTION: Strictly observe posted speed limits, traffic laws, and road conditions when conducting the drive patterns.
   1. Connect a hand-held tester or OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the tester or scan tool ON.
   4. Clear DTCs (where set).
   5. Drive the vehicle to run the HO2 sensor monitor, in accordance with the applicable Drive Pattern described Readiness Monitor Drive Pattern section (see READINESS MONITOR DRIVE PATTERN ).
   6. After conducting the drive pattern, select the following menu items on the tester: DIAGNOSIS / CARB OBD II / O2S TEST RESULT.
      NOTE: This test is not applicable to the A/F sensor. Therefore, even when BANK 1 - SENSOR 1 or BANK 2 - SENSOR 1 is selected on the tester, "NO PARAMETER TO DISPLAY" is displayed by the tester.
   7. All HO2 sensors are listed on the tester screen.
      Fig 19: Identifying Hand-Held Tester Or OBD II Scan Tool Screen Display (1 Of 3)

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   8. Select the desired HO2 sensor from the list and press the ENTER button (a screen such as that shown on the left appears).
   9. Check the Test Value (the Test Item value).
   Fig 20: Identifying Hand-Held Tester Or OBD II Scan Tool Screen Display (2 Of 3)

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   NOTE: Until the HO2 sensor monitor runs to completion, when it fails to complete or when the ignition switch is turned to OFF, the tester screen displays the upper and lower viewable limit values for the monitor (for example, voltages: 0 V and 1.275 V, seconds: 0 and 10.2, Test Value: 0 and 255).
3. Procedure of Reading Test Value (Example).
   NOTE: The values shown below are examples only.
   1. Check the Test Value in the Test Item line.
   2. Use the unit Conversion (conversion factor value) in the (O2S Test Result table to calculate the Test Value.
      • Test Value: 17 x Unit Conversion: 0.3906 = Calculated Value and Unit: 6.6%
   3. Check the calculated Test Value by referring to the Standard Value,
   Fig 21: Identifying Hand-Held Tester Or OBD II Scan Tool Screen Display (3 Of 3)

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1. Description of MONITOR RESULT.

   The Monitor Result is part of the monitoring for malfunctions in emission related components such as the thermostat, catalytic converter, and evaporative e emission system. The various states (Test Items) of the components are monitored by the ECM. The Test Item values (Test Values) can be read using a hand-held tester or OBD II scan tool.

   A Test Value is the latest snapshot data after the vehicle is driven to run the monitor. Therefore, the Test Value is not dynamic data.

   If a Test Value is outside the Test Limit, this indicates that the Test Item is malfunctioning. If a Test Value is on the borderline of the Test Limit, any malfunctions may be concealed in the Test Item.

   Test values are cleared when the ignition switch is turned of OFF.

   Example

   MONITOR STRATEGY
   
   

   Test ID	Test Item	Test Value	Unit Conversion	Unit	Test Limit
   $08	Thermostat	Engine coolant temperature (ECT)	Multiply by 0.625 and minus 40	°C	Malfunction criteria for thermostat

   • Test ID: Code applied to each Test Item
   • Test Item: Component to be monitored in the test
   • Test Value: Value to be monitored
   • Unit Conversion: Conversion factor used to calculated the Test Value displayed on hand-held tester
   • Unit: Unit applied to Test Value
   • Test Limit: The malfunction threshold of Test Item
   NOTE:

   • Specifics of each Test Item, Test Value, Unit Conversion and Test Limit are described in the paragraph titled "MONITOR RESULT" in each DTC section relating to the emission related components.
   • The Monitor Result is not applicable to the Heated Oxygen (HO2) sensor. For more information about the test, refer to O2S TEST RESULT (MODE 05 DATA) .
2. Procedure of MONITOR RESULT.
   CAUTION: Strictly observe posted speed limits, traffic laws, and road conditions when conducting the drive patterns.
   1. Connect a hand-held tester or OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the tester or scan tool ON.
   4. Clear DTCs (where set).
   5. Drive the vehicle to run the monitor, in accordance with the applicable Drive Pattern described in the Readiness Monitor Drive Pattern section (see READINESS MONITOR DRIVE PATTERN ).
   6. After conducting the drive pattern, select the following menu items on the tester: DIAGNOSIS / ENHANCED OBD II / MONITOR INFO / MONITOR RESULT.
   7. The Test Items will appear at the beginning of each line followed by INCMP, PASS or FAIL.
      • INCMP: Stands for incomplete. The judgment process has not yet been finished.
      • PASS: No malfunction has been detected.
      • FAIL: A malfunction has been detected.
      Fig 22: Identifying Hand-Held Tester Or OBD II Scan Tool Screen Display (1 Of 3)

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   8. Select the Test Item (Label) from the list and press the ENTER button. You will see the following screen:
      • VAL: Test Value
      • LMT: Test Limit
      • TLT: Test Limit Type (Either 0 or 1 is displayed)
      Fig 23: Identifying Hand-Held Tester Or OBD II Scan Tool Screen Display (2 Of 3)

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      NOTE:

      • TLT = 0: VAL smaller than LMT indicates Test Item is normal (when the Test is PASS).
      • TLT = 1: VAL larger than LMT indicates Test Item is normal (when the Test is PASS)
      • The Test Value (VAL) is recorded after the monitor is completed.
      • When the Test Value is on the borderline of the Test Limit, the Test Item may have a problem or malfunction.
   9. If necessary, press the HELP to see the information about the TLT.

Fig 24: Identifying Hand-Held Tester Or OBD II Scan Tool Screen Display (3 Of 3)

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1. Description

   This registration section consists of the three parts, Input Instructions, Read VIN and Write VIN.

   1. Input Instructions: Explains the general VIN input instructions suing a head-held tester.
   2. Read VIN: Explains the VIN reading process with the flowchart. This process allows the VIN stored in the ECM to be read, in order to confirm that the two VINs, provided to the vehicle and stored in the vehicle's ECM, are the same.
   3. Write VIN: Explains the VIN writing process with the flowchart. This process allows he 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
   1. Hand-held tester
      • The allow buttons (UP, DOWN, RIGHT and LEFT) and numerical buttons (0 to 9) are used, in order to input the VIN.
   2. Cursor Operation
      • To move the cursor on the tester screen, press the RIGHT or LEFT buttons.
   3. alphabetical Character Input
      • Press the UP or DOEN buttons to select the desired alphabetical character.
      • After selection, shift the cursor.
   4. Numeric Character Input
      • Press the numerical buttons corresponding to the number that you want to input.
      • After input, shift the cursor.
      NOTE: The numerical characters can be selected by using the UP or DOWN buttons.
   5. Correction
      • When correcting the input character(s), put the cursor onto the character using the RIGHT or LEFT buttons.
      • Select or input a correct character using the UP/DOWN buttons, or the numerical buttons.
   6. Finishing Input Operation
   • Make sure that the input VIN matches with the vehicle VIN after input.
   • Press the ENTER button on the tester.

1. Read VIN using the hand-held tester.

Fig 25: Read VIN Flow Chart

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1. Write VIN using the hand-held tester.

Fig 26: Write VIN Flow Chart (1 Of 2)

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Fig 27: Write VIN Flow Chart (2 Of 2)

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