Introduction: Overview Toyota Tacoma II

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1. GENERAL DESCRIPTION This article is written in accordance with SAE J2008. Diagnosis Removing / Installing, Replacing, Disassembling / Reassembling, Checking and Adjusting Final Inspection The following procedures are omitted from this article. However, these procedures must be performed. Use a jack or lift to perform operations. Clean all removed parts. Perform a visual check.
2. PREPARATION Use of Special Service Tools (SST) and Special Service Materials (SSM) may be required, depending on the repair procedure. Be sure to use SST and SSM when they are required and follow the working procedures properly. A list of SST and SSM is in the «PREPARATION»(/toyota/tacoma/ii-2004-2011/remont/cruise-control-systems/#preparation) article.
3. REPAIR PROCEDURES A component illustration is placed under the title where necessary. Non-reusable parts, grease application areas, precoated parts and torque specifications are noted in the component illustrations. The following illustration is an example. Torque specifications, grease application areas and non-reusable parts are emphasized in the procedures. HINT: There are cases where such information can only be explained by using an illustration. In these cases, torque, oil and other information are described in the illustration. Only items with key points are described in the text. What to do and other details are explained using illustrations next to the text. Both the text and illustrations are accompanied by standard values and notices. ILLUSTRATION DESCRIPTION Illustration What to do and where to do it Task heading What work will be performed Explanation text How to perform the task Information such as specifications and warnings, which are written in boldface text Illustrations of similar vehicle models are sometimes used. In these cases, minor details may be different from the actual vehicle. Procedures are presented in a step-by-step format.
4. SERVICE SPECIFICATIONS SPECIFICATIONS are presented in boldface text throughout the article. The specifications are also found in the «SERVICE SPECIFICATIONS»(ref-263617) article for reference.
5. TERM DEFINITIONS TERM DEFINITIONS CAUTION Possibility of injury to you or other people. NOTICE Possibility of damage to components being repaired. HINT Provides additional information to help you perform repairs.
6. INTERNATIONAL SYSTEM OF UNITS The units used in this article comply with the International System of Units (SI UNIT) standard. Units from the metric system and the English system are also provided. Example: Torque: 30 N*m (310 kgf*cm, 22 ft.*lbf)

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1. VEHICLE IDENTIFICATION NUMBER The vehicle identification number is stamped on the vehicle body and on the certification label (Scheme 2) A: Vehicle Identification Number B: Certification Label
2. ENGINE SERIAL NUMBER AND TRANSMISSION SERIAL NUMBER The engine serial number is stamped on the cylinder block of the engine and the transmission serial number is stamped on the housing (Scheme 3) A: Engine Serial Number B: Transmission Serial Number

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1. BASIC REPAIR HINT HINTS ON OPERATIONS JACKING UP AND SUPPORTING VEHICLE Care must be taken when jacking up and supporting the vehicle. Be sure to lift and support the vehicle at the proper locations. PRECOATED PARTS Precoated parts are bolts and nuts that are coated with a seal lock adhesive at the factory. If a precoated part is retightened, loosened or moved in any way, it must be recoated with the specified adhesive. When reusing a precoated part, clean off the old adhesive and dry the part with compressed air. Then apply new seal lock adhesive appropriate to that part. Some seal lock agents harden slowly. You may have to wait for the seal lock adhesive to harden. GASKETS When necessary, use a sealer on gaskets to prevent leaks. BOLTS, NUTS AND SCREWS Carefully follow all the specifications for tightening torques. Always use a torque wrench. FUSES When inspecting a fuse, check that the wire of the fuse is not broken. When replacing fuses, be sure that the new fuse has the correct amperage rating. Do not exceed the rating or use one with a lower rating. FUSE REFERENCE Illustration Symbol Part Name Abbreviation FUSE FUSE MEDIUM CURRENT FUSE M-FUSE HIGH CURRENT FUSE H-FUSE FUSIBLE LINK FL CIRCUIT BREAKER CB CLIPS The removal and installation methods of typical clips used for vehicle body parts are shown in «CLIP REMOVING/INSTALLING PROCEDURES»(ref-263615-S30798554862007091100000). HINT: If clips are damaged during a procedure, always replace the damaged clip with a new clip. CLIP REMOVING/INSTALLING PROCEDURES Shape (Example) Illustration Procedures Remove the clips with a clip remover or pliers. Remove the clips with a clip remover or screwdriver. Remove the clips with a wide scraper to prevent panel damage. Remove the clips by pushing the center pin through and prying out the shell. Remove the clips by unscrewing the center pin and prying out the shell. Remove the clips by prying out the pin and then prying out the shell. CLAWS The removal and installation methods of typical claws used for vehicle body parts are shown in «CLAW REMOVING/INSTALLING PROCEDURES»(ref-263615-S29138532852007091100000). HINT: If claws are damaged during a procedure, always replace the damaged claws with new caps or covers. CLAW REMOVING/INSTALLING PROCEDURES Shape (Example) Illustration Procedures Using a screwdriver, detach the claws and remove the cap or covers. Using a screwdriver, detach the claws and remove the cap or covers. Using a screwdriver, detach the claws and remove the cap or covers. REMOVAL AND INSTALLATION OF VACUUM HOSES To disconnect a vacuum hose, pull and twist from the end of the hose. Do not pull from the middle of the hose as this may cause damage. When disconnecting vacuum hoses, use tags to identify where they should be reconnected. After completing any hose related repairs, double check that the vacuum hoses are properly connected. The label under the hood shows the proper layout. When using a vacuum gauge, never force the hose onto a connector that is too large. If a hose has been stretched, it may leak air. Use a step-down adapter if necessary. TORQUE WHEN USING TORQUE WRENCH WITH EXTENSION TOOL Use the formula below to calculate special torque values for situations where SST or an extension tool is combined with a torque wrench. Formula: T' = L2 / (L1 + L2) * T TORQUE VALUES DESCRIPTION T' Reading of torque wrench {N*m (kgf*cm, ft.*lbf)} T Torque {N*m (kgf*cm, ft.*lbf)} L1 Length of SST or extension tool {cm (in.)} L2 Length of torque wrench {cm (in.)} NOTE: If an extension tool or SST is combined with a torque wrench and the wrench is used to tighten to a torque specification in this article, the actual torque will be excessive and parts will be damaged.
2. FOR VEHICLES EQUIPPED WITH SRS AIRBAG AND FRONT SEAT OUTER BELT ASSEMBLY WITH PRETENSIONER The TOYOTA TACOMA is equipped with a Supplemental Restraint System (SRS). CAUTION: Failure to carry out the service operations in the correct sequence could cause the SRS to unexpectedly deploy during servicing and lead to serious injury. Furthermore, if a mistake is made when servicing the SRS, it is possible that the SRS may fail to operate properly. Before servicing (including removal or installation of parts, inspection or replacement), be sure to read the following part of the article carefully. GENERAL NOTICE As malfunctions of the SRS are difficult to confirm, the Diagnostic Trouble Codes (DTCs) become the most important source of information when troubleshooting. When troubleshooting the SRS, always check the DTCs before disconnecting the battery. Work must be started at least 90 seconds after the ignition switch is turned OFF and after the cable is disconnected from the negative (-) battery terminal. (The SRS is equipped with a backup power source. If work is started within 90 seconds after turning the ignition switch OFF and disconnecting the cable from the negative (-) battery terminal, the SRS may deploy. When the cable is disconnected from the negative (-) battery terminal, clock and audio system memory is erased. Before starting work, make a note of the settings of each memory system. When work is finished, reset the clock and audio system as before. CAUTION: Never use a backup power source (battery or other) to avoid erasing system memory. The backup power source may inadvertently power the SRS and cause it to deploy. Even in cases of a minor collision where the SRS does not deploy, the steering wheel pad, front passenger airbag assembly, front seat side airbag assembly, curtain shield airbag assembly and seat belt pretensioner should be inspected In minor collisions where the SRS does not deploy, the steering wheel pad, front passenger airbag assembly, front seat side airbag assembly, curtain shield airbag assembly and seat belt pretensioner should be inspected before further use of the vehicle. Never use SRS parts from another vehicle. When replacing parts, use new parts. Before repairs, remove the airbag sensor assemblies if impacts are likely to be applied to the sensor during repairs. Never disassemble and attempt to repair the steering wheel pad, front passenger airbag assembly, side airbag assembly, curtain shield airbag assembly and seat belt pretensioner. Replace the steering wheel pad, front passenger airbag assembly, front seat side airbag assembly, curtain shield airbag assembly and seat belt pretensioner if: 1) damage has occurred from being dropped, or 2) cracks, dents or other defects in the case, bracket or connector are present. Do not directly expose the airbag sensor assemblies or airbag assemblies to hot air or flames. Use an ohmmeter/voltmeter with high impedance (10 k/V minimum) for troubleshooting electrical circuits. Information labels are attached to the SRS components. Follow the instructions on the labels. After work on the SRS is completed, check the SRS warning light. SPIRAL CABLE The steering wheel must be fitted correctly to the steering column with the spiral cable at the neutral position, as cable disconnection and other problems may occur. Refer to the information about correct installation of the steering wheel. STEERING PAD Always place a removed or new steering pad surface upward (Scheme 12) Placing the horn button with the pad surface facing down could cause a serious accident if the airbag inflates. Also, do not place anything on top of the horn button. Never measure the resistance of the airbag squib. This may cause the airbag to inflate, which could cause serious injury. Grease or detergents of any kind should not be applied to the horn button. Store the horn button assembly in an area where the ambient temperature is below 93°C (200°F), the humidity is not high and there is no electrical noise. When using electric welding anywhere on the vehicle, disconnect the airbag ECU connectors (4 pins). These connectors contain shorting springs. This feature reduces the possibility of the airbag deploying due to currents entering the squib wiring. When disposing of the vehicle or the horn button assembly by itself, the airbag should be deployed using SST before disposal. Activate the airbag in a safe place away from electrical noise. FRONT PASSENGER AIRBAG ASSEMBLY Always place a removed or new front passenger airbag assembly with the pad surface facing upward (Scheme 14) Placing the airbag assembly with the airbag inflation direction facing down could cause a serious accident if the airbag inflates. Never measure the resistance of the airbag squib. This may cause the airbag to inflate, which could cause serious injury. Grease or detergents of any kind should not be applied to the front passenger airbag assembly. Store the airbag assembly in an area where the ambient temperature is below 93°C (200°F), the humidity is not high and there is no electrical noise. When using electric welding anywhere on the vehicle, disconnect the airbag ECU connectors (4 pins). These connectors contain shorting springs. This feature reduces the possibility of the airbag deploying due to currents entering the squib wiring. When disposing of the vehicle or the airbag assembly unit by itself, the airbag should be deployed using SST before disposal. Activate the airbag in a safe place away from electrical noise. CURTAIN SHIELD AIRBAG ASSEMBLY Always place a removed or new curtain shield airbag assembly in a clear plastic bag, and keep it in a safe place. CAUTION: The plastic bag is not reusable. NOTE: Never disassemble the curtain shield airbag assembly. Never measure the resistance of the airbag squib. This may cause the airbag to inflate, which could cause serious injury. Grease or detergents of any kind should not be applied to the curtain shield airbag assembly. Store the airbag assembly in an area where the ambient temperature is below 93°C (200°F), the humidity is not high and there is no electrical noise. When using electric welding anywhere on the vehicle, disconnect the airbag ECU connectors (4 pins). These connectors contain shorting springs. This feature reduces the possibility of the airbag deploying due to currents entering the squib wiring. When disposing of a vehicle or the airbag assembly unit by itself, the airbag should be deployed using SST before disposal. Activate the airbag in a safe place away from electrical noise. FRONT SEAT SIDE AIRBAG ASSEMBLY Always place a removed or new front seat airbag assembly with the airbag inflation direction facing up. Never measure the resistance of the airbag squib. This may cause the airbag to inflate, which could cause serious injury. Grease or detergents of any kind should not be applied to the front seat airbag assembly. Store the airbag assembly in an area where the ambient temperature is below 93°C (200°F), the humidity is not high and there is no electrical noise. When using electric welding anywhere on the vehicle, disconnect the airbag ECU connectors (2 pins). These connectors contain shorting springs. This feature reduces the possibility of the airbag deploying due to currents entering the squib wiring. When disposing of a vehicle or the airbag assembly unit by itself, the airbag should be deployed using SST before disposal. Activate the airbag in a safe place away from electrical noise. FRONT SEAT OUTER BELT ASSEMBLY WITH PRETENSIONER Never measure the resistance of the seat outer belt. This may cause the pretensioner of the seat belt to activate, which could cause serious injury. Never disassemble the seat outer belt. Never install the seat outer belt on another vehicle. Store the seat outer belt in an area where the ambient temperature is below 80°C (176°F), the humidity is not high and there is no electrical noise. When using electric welding anywhere on the vehicle, disconnect the airbag ECU connectors (2 pins). These connectors contain shorting springs. This feature reduces the possibility of the pretensioner deploying due to currents entering the squib wiring. When disposing of a vehicle or the seat outer belt assembly by itself, the seat outer belt should be activated before disposal. Activate it in a safe place away from electrical noise. As the seat outer belt is hot after the pretensioner is activated, allow some time for it to cool down sufficiently before disposal. Never apply water to try to cool down the seat outer belt. Grease, detergents, oil or water should not be applied to the front seat outer belt. AIRBAG SENSOR ASSEMBLY Never reuse an airbag sensor assembly that has been involved in a collision where the SRS has deployed. The connectors to the airbag sensor assembly should be connected or disconnected with the sensor placed on the floor. If the connectors are connected or disconnected while the airbag sensor assembly is not placed on the floor, the SRS may activate. Work must be started at least 90 seconds after the ignition switch is turned OFF and the cable is disconnected from the negative (-) battery terminal, even if only loosening the set bolts of the airbag sensor assembly. WIRE HARNESS AND CONNECTOR The SRS wire harness is integrated with the instrument panel wire harness assembly. All the connectors in the system are a standard yellow color. If the SRS wire harness becomes disconnected or the connector becomes broken, repair or replace it.
3. ELECTRONIC CONTROL REMOVAL AND INSTALLATION OF BATTERY TERMINAL NOTE: Certain systems need to be initialized after disconnecting and reconnecting the cable from the negative (-) battery terminal. Before performing electronic work, disconnect the cable from the negative (-) battery terminal to prevent component and wire damage caused by accidental short circuits. When disconnecting the cable, turn the ignition switch off and the headlight dimmer switch OFF and loosen the cable nut completely. Perform these operations without twisting or prying the cable. Then disconnect the cable. Clock settings, radio settings, audio system memory, DTCs and other data are erased when the cable is disconnected from the negative (-) battery terminal. Write down any necessary data before disconnecting the cable. HANDLING OF ELECTRONIC PARTS Do not open the cover or case of the ECU unless absolutely necessary. If the IC terminals are touched, the IC may be rendered inoperative by static electricity. Do not pull the wires when disconnecting electronic connectors. Pull the connector. Be careful not to drop electronic components, such as sensors or relays. If they are dropped on a hard surface, they should be replaced. When cleaning the engine with steam, protect the electronic components, air filter and emission-related components from water. Never use an impact wrench to remove or install temperature switches or temperature sensors. When measuring the resistance of a wire connector, insert the tester probe carefully to prevent terminals from bending.
4. REMOVAL AND INSTALLATION OF FUEL CONTROL PARTS PLACE FOR REMOVING AND INSTALLING FUEL SYSTEM PARTS Work in a location with good air ventilation that does not have welders, grinders, drills, electric motors, stoves, or any other ignition sources. Never work in a pit or near a pit as vaporized fuel will collect in those places. REMOVING AND INSTALLING FUEL SYSTEM PARTS Prepare a fire extinguisher before starting the operation. To prevent static electricity, install a ground wire to the fuel changer, vehicle and fuel tank, and do not spray the surrounding area with water. Be careful when performing work in this area, as the work surface will become slippery. Do not clean up gasoline spills with water, as this may cause the gasoline to spread, and possibly create a fire hazard. Avoid using electric motors, working lights and other electric equipment that can cause sparks or high temperatures. Avoid using iron hammers as they may create sparks. Dispose of fuel-contaminated cloth separately using a fire resistant container.
5. REMOVAL AND INSTALLATION OF ENGINE INTAKE PARTS If any metal particles enter inlet system parts, they may damage the engine. When removing and installing inlet system parts, cover the openings of the removed parts and engine openings. Use gummed tape or other suitable materials. When installing inlet system parts, check that no metal particles have entered the engine or the installed parts.
6. HANDLING OF HOSE CLAMPS Before removing the hose, check the clamp position so that it can be reinstalled in the same position. Replace any deformed or dented clamps with new ones. When reusing a hose, attach the clamp on the clamp track portion of the hose. For a spring type clamp, you may want to spread the tabs slightly after installation by pushing in the direction of the arrows (Scheme 24)
7. FOR VEHICLES EQUIPPED WITH MOBILE COMMUNICATION SYSTEMS Install the antenna as far away from the ECU and sensors of the vehicle electronic systems as possible. Install an antenna feeder at least 20 cm (7.87 in.) away from the ECU and sensors of the vehicle electronic systems. For details about ECU and sensor locations, refer to the section of the applicable components. Keep the antenna and feeder separate from other wiring as much as possible. This will prevent signals from the communication equipment from affecting vehicle equipment and vice versa. Check that the antenna and feeder are correctly adjusted. Do not install a high-powered mobile communication system.
8. FOR VEHICLES EQUIPPED WITH TRACTION CONTROL (TRAC) SYSTEM When testing with a 2-wheel drum tester such as a speedometer tester, a combination tester of the speedometer and brake, a chassis dynamometer, or when jacking up the front wheels and driving the wheels, always turn the TRAC system OFF. Confirm that the TRAC system is OFF. Ignition switch to OFF. Connect SST to terminals TS and CG of DLC3. NOTE: Confirm that the VSC/TRAC warning light blinks. Begin testing. Disconnect SST from DLC3. Check that the VSC/TRAC warning light turns OFF. HINT: The SLIP indicator light blinks when the TRAC system is operating.
9. FOR VEHICLES EQUIPPED WITH VEHICLE STABILITY CONTROL (VSC) SYSTEM NOTICES WHEN USING DRUM TESTER Before beginning testing, to disable the VSC, turn the ignition switch OFF and connect SST to terminals TS and CG of the DLC3. SST 09843-18040 NOTE: Confirm that the VSC warning light blinks. VSC system will be reset when the engine is restarted. For safety, secure the vehicle with restraint chains while using a wheel dynamometer. NOTICES OF RELATED OPERATIONS TO VSC Do not carry out unnecessary installation and removal as it might affect the adjustment of VSC related parts. Be sure to follow the instructions for work preparation and final confirmation of proper operation of the VSC system.
10. FOR VEHICLES EQUIPPED WITH CATALYTIC CONVERTER CAUTION: If a large amount of unburned gasoline or gasoline vapors flow into the converter, it may cause overheating and create a fire hazard. To prevent this, observe the following precautions. Use only unleaded gasoline. Avoid idling the engine for more than 20 minutes. Avoid performing unnecessary spark jump tests. Perform a spark jump test only when absolutely necessary. Perform this test as rapidly as possible. While testing, never race the engine. Avoid a prolonged engine compression measurement. Engine compression measurements must be performed as rapidly as possible. Do not run the engine when the fuel tank is nearly empty. This may cause the engine to misfire and create an extra load on the converter.

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1. NOTICE ABOUT VEHICLE CONDITION WHEN JACKING UP VEHICLE The vehicle must be unloaded before jacking up/lifting up the vehicle. Never jack up/lift up a heavily loaded vehicle. When removing heavy parts such as the engine and transmission, the center of gravity of the vehicle may shift. To stabilize the vehicle, place a balance weight in a location where it will not roll or shift, or use a mission jack to hold the jacking support.
2. NOTICE FOR USING FOR POST LIFT Follow the safety procedures outlined in the lift instruction manual. Use precautionary measures to prevent the free wheel beam from damaging tires or wheels. Use wheel chocks to secure the vehicle.
3. NOTICE FOR USING JACK AND SAFETY STAND Work on a level surface. Use wheel chocks at all times. Set the jack and rigid racks to the specified locations of the vehicle accurately. When jacking up the vehicle, first release the parking brake and move the shift lever to N. When jacking up the entire vehicle: When jacking up the front wheels first, make sure wheel chocks are behind the rear wheels. When jacking up the rear wheels first, make sure wheel chocks are in front of the front wheels. When jacking up only the front or rear wheels of the vehicle: Before jacking up the front wheels, place wheel chocks on both sides of the rear wheels. Before jacking up the rear wheels, place wheel chocks on both sides of the front wheels. When lowering a vehicle that only has its front or rear wheels jacked up: Before lowering the front wheels, make sure wheel chocks are in front of the rear wheels. Before lowering the rear wheels, make sure wheel chocks are behind the front wheels. It is extremely dangerous to perform any work on a vehicle raised on a jack alone, even for work that can be finished quickly. Rigid racks must be used to support the vehicle.
4. NOTICE FOR USING SWING ARM TYPE LIFT Follow safety procedures outlined in its instruction manual. Use a swing arm equipped with a rubber attachment. Set in the vehicle so as to make its center of gravity as close as possible to the center of the lift. (L becomes short.) Place the vehicle horizontally by adjusting the height of the cradle, and match the groove of the cradle and the safety stand support location accurately. Be sure to lock the swing arms before lifting and during work (if equipped with arm locks). Lift the vehicle up off the ground. Stand at a safe distance and shake the vehicle to check its stability.

GENERAL INFORMATION

A large number of ECU controlled systems are used in the TOYOTA TACOMA. In general, ECU controlled systems are considered to be very intricate, requiring a high level of technical knowledge to troubleshoot. However, most problem checking procedures only involve inspecting the ECU controlled system's circuits one by one. An adequate understanding of the system and a basic knowledge of electricity is enough to perform effective troubleshooting, accurate diagnoses and necessary repairs.

FOR USING INTELLIGENT TESTER

Connect the cable of the intelligent tester (with CAN VIM) to the DLC3, turn the ignition switch ON and attempt to use the tester. If the display indicates that a communication error has occurred, there is a problem either with the vehicle or with the tester.

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1. * If communication is normal when the tester is connected to another vehicle, inspect the DLC3 of the original vehicle.
2. * If communication is still not possible when the tester is connected to another vehicle, the problem may be in the tester itself. Consult the Service Department listed in the tester's instruction manual.

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1. OPERATION FLOW HINT: Perform troubleshooting in accordance with the procedures below. The following is an outline of basic troubleshooting procedures. Confirm the troubleshooting procedures for the circuit you are working on before beginning troubleshooting. VEHICLE BROUGHT TO WORKSHOP CUSTOMER PROBLEM ANALYSIS Ask the customer about the conditions and environment when the problem occurred. INSPECT BATTERY VOLTAGE Standard voltage: 11 to 14 V If the voltage is below 11 V, recharge or replace the battery before proceeding. SYMPTOM CONFIRMATION AND DTC (AND FREEZE FRAME DATA) CHECK Visually check the wire harnesses, connectors and fuses for open and short circuits. Warm up the engine to the normal operating temperature. Confirm the problem symptoms and conditions, and check for DTCs. Result RESULT REFERENCE Result Proceed to DTC is output A DTC is not output B B: Go to step 6 A: Go to Next Step DTC TABLE Check the results obtained in "SYMPTOM CONFIRMATION AND DTC (AND FREEZE FRAME DATA) CHECK". Then find the output DTC in the DTC table. Look at the "Trouble Area" column for a list of potentially malfunctioning circuits and/or parts. NEXT: Go to step 7 PROBLEM SYMPTOMS TABLE Check the results obtained in "SYMPTOM CONFIRMATION AND DTC (AND FREEZE FRAME DATA) CHECK". Then find the problem symptoms in the problem symptoms table. Look at the "Suspected Area" column for a list of potentially malfunctioning circuits and/or parts. CIRCUIT INSPECTION OR PARTS INSPECTION Confirm the malfunctioning circuit or part. ADJUST, REPAIR OR REPLACE Adjust, repair or replace the malfunctioning circuit or parts. CONFIRMATION TEST After the adjustment, repairs or replacement, confirm that the malfunction no longer exists. If the malfunction does not reoccur, perform a confirmation test under the same conditions and in the same environment as when the malfunction occurred the first time. NEXT: END
2. CUSTOMER PROBLEM ANALYSIS HINT: In troubleshooting, confirm that the problem symptoms have been accurately identified. Preconceptions should be discarded in order to make an accurate judgment. To clearly understand what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time the malfunction occurred. Gather as much information as possible for reference. Past problems that seem unrelated may also help in some cases. The following 5 items are important points in the problem analysis: CUSTOMER PROBLEM ANALYSIS What Vehicle model, system name When Date, time, occurrence frequency Where Road conditions Under what conditions? Running conditions, driving conditions, weather conditions How did it happen? Problem symptoms
3. SYMPTOM CONFIRMATION AND DIAGNOSTIC TROUBLE CODE HINT: The diagnostic system in the TOYOTA TACOMA has various functions. The first function is the Diagnostic Trouble Code (DTC) check. A DTC is a code stored in the ECU memory whenever a malfunction in the signal circuits to the ECU occurs. In a DTC check, a previous malfunction's DTC can be checked by a technician during troubleshooting. Another function is the Input Signal Check, which checks if the signals from various switches are sent to the ECU correctly. By using these functions, the problem areas can be narrowed down and troubleshooting is more effective. Diagnostic functions are incorporated in the following system in the TOYOTA TACOMA. SYSTEM DIAGNOSTIC FUNCTIONS System DTC Check (Normal Mode) DTC Check (Check Mode) Freeze-frame Data Sensor Check/Test Mode (Input Signal Check) Data List Active Test Customize Parameter 1GR-FE SFI SYSTEM O O O - O O - 2TR-FE SFI SYSTEM O O O - O O - A340E AUTOMATIC TRANSAXLE SYSTEM O O - - O O - A750E AUTOMATIC TRANSAXLE SYSTEM O O - - O O - A750F AUTOMATIC TRANSAXLE SYSTEM O O - - O O - TIRE PRESSURE WARNING SYSTEM O - - - O - - ANTI-LOCK BRAKE SYSTEM O - O O O O - VEHICLE STABILITY CONTROL SYSTEM O - O O O O - AIRBAG SYSTEM O O - - O - - OCCUPANT CLASSIFICATION SYSTEM O - - - O - - ENGINE IMMOBILIZER SYSTEM O - - - O - - CRUISE CONTROL SYSTEM O - - - O - - METER/GAUGE SYSTEM - - - - O - - AUDIO AND VISUAL SYSTEM O O - - - - - CAN COMMUNICATION SYSTEM O - - - - - - In the DTC check, it is very important to determine whether the problem indicated by the DTC is either: 1) still occurring, or 2) occurred in the past but has since returned to normal. In addition, the DTC should be compared to the problem symptom to see if they are related. For this reason, DTCs should be checked before and after confirmation of symptoms (i.e., whether or not problem symptoms exist) to determine current system conditions, as shown in the flow chart below. Never skip the DTC check. Failing to check DTCs may, depending on the case, result in unnecessary troubleshooting for systems operating normally or lead to repairs not related to the problem. Follow the procedures listed in the flow chart in the correct order. The following flow chart shows how to proceed with troubleshooting using the DTC check. Directions from the flow chart will indicate how to proceed either to DTC troubleshooting or to the troubleshooting of each problem symptom. DTC CHECK MAKE A NOTE OF DTCS DISPLAYED AND THEN CLEAR MEMORY SYMPTOM CONFIRMATION Result RESULT REFERENCE Result Proceed to No symptoms exist A Symptoms exist B B: Go to step 5 A: Go to Next Step SIMULATION TEST USING SYMPTOM SIMULATION METHODS DTC CHECK Result RESULT REFERENCE Result Proceed to DTC is not output A DTC is output B B: TROUBLESHOOTING OF PROBLEM INDICATED BY DTC A: GO TO NEXT STEP SYMPTOM CONFIRMATION Result RESULT REFERENCE Result Proceed to Symptoms exist A No symptoms exist B If a DTC was displayed in the initial DTC check, the problem may have occurred in a wire harness or connector in that circuit in the past. Check the wire harness and connectors. B: SYSTEM NORMAL A: TROUBLESHOOTING OF EACH PROBLEM SYMPTOM The problem is still occurring in a place other than the diagnostic circuit (the DTC displayed first is either for a past problem or a secondary problem).
4. SYMPTOM SIMULATION HINT: The most difficult case in troubleshooting is when no problem symptoms occur. In such a case, a thorough problem analysis must be carried out. A simulation of the same or similar conditions and environment in which the problem occurred in the customer's vehicle should be carried out. No matter how much skill or experience a technician has, troubleshooting without confirming the problem symptoms will lead to important repairs being overlooked and mistakes or delays. For example: With a problem that only occurs when the engine is cold or as a result of vibration caused by the road during driving, the problem can never be determined if the symptoms are being checked on a stationary vehicle or on a vehicle with a warmed-up engine. Vibration, heat or water penetration (moisture) is difficult to reproduce. The symptom simulation tests below are effective substitutes for the conditions and can be applied on a stationary vehicle. Important points in the symptom simulation test: In the symptom simulation test, the problem symptoms as well as the problem area or parts must be confirmed. First, narrow down the possible problem circuits according to the symptoms. Then, connect the tester and carry out the symptom simulation test, judging whether the circuit being tested is defective or normal. Also, confirm the problem symptoms at the same time. Refer to the problem symptoms table for each system to narrow down the possible causes. VIBRATION METHOD: When a malfunction seems to occur as a result of vibration. PART AND SENSOR Apply slight vibration with a finger to the part of the sensor suspected to be the cause of the problem, and check whether or not the malfunction occurs. NOTE: Applying strong vibration to relays may open them. CONNECTORS Slightly shake the connector vertically and horizontally. WIRE HARNESS Slightly shake the wire harness vertically and horizontally. HINT: The connector joint and fulcrum of the vibration are the major areas that should be checked thoroughly. HEAT METHOD: When a malfunction seems to occur when the area in question is heated. Heat the component that is the possible cause of the malfunction with a hair dryer or similar device. Check if the malfunction occurs. NOTE: Do not heat to more than 60°C (140°F). Exceeding this temperature may damage components. Do not apply heat directly to the parts in the ECU. WATER SPRINKLING METHOD: When a malfunction seems to occur on a rainy day or in high-humidity. Sprinkle water onto the vehicle and check if the malfunction occurs. NOTE: Never sprinkle water directly into the engine compartment. Indirectly change the temperature and humidity by spraying water onto the front of the radiator. Never apply water directly onto the electronic components. HINT: If the vehicle has or had a water leakage problem, the leakage may have damaged the ECU or connections. Look for evidence of corrosion or short circuits. Proceed with caution during water tests. HIGH ELECTRICAL LOAD METHOD: When a malfunction seems to occur when electrical load is excessive. Turn on the heater blower, headlight, rear window defogger and all other electrical loads. Check if the malfunction reoccurs.
5. DIAGNOSTIC TROUBLE CODE TABLE Look for output Diagnostic Trouble Codes (DTCs) (from the DTC checks) in the appropriate section's Diagnostic Trouble Code Table. Use the table to determine the trouble area and the proper inspection procedure. A description of each of the table columns are below. DIAGNOSTIC TROUBLE CODE REFERENCE Item Description DTC No. Indicates the diagnostic trouble code Detection Item Indicates the system or details of the problem Trouble Area Indicates the suspect areas of the problem
6. PROBLEM SYMPTOMS TABLE When a "Normal" code is output during a DTC check but the problem is still occurring, use the Problem Symptoms Table. The suspected areas (circuits or parts) for each problem symptom are in the table. The suspected areas are listed in order of probability. A description of each of the table columns are below. HINT: In some cases, the problem is not detected by the diagnostic system even though a problem symptom is present. It is possible that the problem is occurring outside the detection range of the diagnostic system, or that the problem is occurring in a completely different system. PROBLEM SYMPTOMS REFERENCE Item Description Problem Symptom - Circuit Inspection, Inspection Order Indicates the order in which the circuits need to be checked Circuit or Part Name Indicates the circuit or part which needs to be checked
7. CIRCUIT INSPECTION A description of the main areas of each circuit inspection is below. CIRCUIT INSPECTION DESCRIPTION Item Description Circuit Description The major role, operation of the circuit and its component parts are explained. Diagnostic Trouble Code No. and Detection Item Indicates the diagnostic trouble codes, diagnostic trouble code settings and suspected areas for a problem Wiring Diagram This shows a wiring diagram of the circuit. Use this diagram together with ELECTRICAL WIRING DIAGRAM to thoroughly understand the circuit. Wire colors are indicated by an alphabetical code: B = Black L = Blue R = Red BR = Brown LG = Light Green V = Violet G = Green O = Orange W = White GR = Gray P = Pink Y = Yellow SB = Sky Blue The first letter indicates the basic wire color and the second letter indicates the color of the stripe. Inspection Procedures Use the inspection procedures to determine if the circuit is normal or abnormal. If abnormal, use the inspection procedures to determine whether the problem is located in the sensors, actuators, wire harnesses or ECU. Indicates the condition of the connector of the ECU during the check Connector being checked is connected. Connections of tester are indicated by (+) or (-) after the terminal name. Connector being checked is disconnected. For illustrations of inspections between a connector and body ground, information about the body ground is not shown in the illustration.

Scheme 57

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Scheme 70

1. BASIC INSPECTION WHEN MEASURING RESISTANCE OF ELECTRONIC PARTS Unless otherwise stated, all resistance measurements should be made at an ambient temperature of 20°C (68°F). Resistance measurements may be inaccurate if measured at high temperatures, i.e. immediately after the vehicle has been running. Measurements should be made after the engine has cooled down. HANDLING CONNECTORS When disconnecting a connector, first squeeze the mating halves tightly together to release the lock, and then press the lock claw and separate the connector. When disconnecting a connector, do not pull on the harnesses. Grasp the connector directly and separate it. Before connecting a connector, check that there are no deformed, damaged, loose or missing terminals. When connecting a connector, press firmly until it locks with a "click" sound. If checking a connector with a TOYOTA electrical tester, check the connector from the backside (harness side) using a mini test lead. NOTE: As a waterproof connector cannot be checked from the backside, check it by connecting a sub-harness. Do not damage the terminals by moving the inserted tester needle. CHECKING CONNECTORS Checking when a connector is disconnected: Squeeze the connector together to confirm that they are fully connected and locked. Checking when a connector is disconnected: Check by pulling the wire harness lightly from the backside of the connector. Look for unlatched terminals, missing terminals, loose crimps or broken conductor wires. Check visually for corrosion, metallic or foreign matter and water, and bent, rusted, overheated, contaminated, or deformed terminals. Checking the contact pressure of the terminal: Prepare a spare male terminal. Insert it into a female terminal, and check for ample tension when inserting and after full engagement. NOTE: When testing a gold-plated female terminal, always use a gold-plated male terminal. REPAIR METHOD OF CONNECTOR TERMINAL If there is any foreign matter on the terminal, clean the contact point using an air gun or cloth. Never rub the contact point using sandpaper as the plating may come off. If there is abnormal contact pressure, replace the female terminal. If the male terminal is gold-plated (gold color), use a gold-plated female terminal; if it is silver-plated (silver color), use a silver-plated female terminal. Damaged, deformed, or corroded terminals should be replaced. If the terminal does not lock into the housing, the housing may have to be replaced. HANDLING OF WIRE HARNESS If removing a wire harness, check the wiring and clamping before proceeding so that it can be restored in the same way. Never twist, pull or slacken the wire harness more than necessary. The wire harness should never come into contact with a high temperature part, or rotating, moving, vibrating or sharp-edged parts. Avoid contact with panel edges, screw tips and other sharp items. When installing parts, never pinch the wire harness. Never cut or break the cover of the wire harness. If it is cut or broken, replace it or repair it with vinyl tape.
2. CHECK FOR OPEN CIRCUIT For an open circuit in the wire harness in (Scheme 39), check the resistance or voltage, as described below. Check the resistance. Disconnect connectors A and C and measure the resistance between them. Standard resistance (Scheme 40) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition Connector A terminal 1 - Connector C terminal 1 10 k or higher Connector A terminal 2 - Connector C terminal 2 Below 1 HINT: Measure the resistance while lightly shaking the wire harness vertically and horizontally. If the results match the examples above, an open circuit exists between terminal 1 of connector A and terminal 1 of connector C. Disconnect connector B and measure the resistance between the connectors. Standard resistance (Scheme 41) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition Connector A terminal 1 - Connector B1 terminal 1 Below 1 Connector B2 terminal 1 - Connector C terminal 1 10 k or higher If the results match the examples above, an open circuit exists between terminal 1 of connector B2 and terminal 1 of connector C. Check the voltage. In a circuit in which voltage is applied to the ECU connector terminal, an open circuit can be checked by conducting a voltage check. With each connector still connected, measure the voltage between the body ground and these terminals (in this order): 1) terminal 1 of connector A, 2) terminal 1 of connector B, and 3) terminal 1 of connector C. Standard voltage (Scheme 42) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition Connector A terminal 1 - Body ground 5 V Connector B terminal 1 - Body ground 5 V Connector C terminal 1 - Body ground Below 1 V If the results match the examples above, an open circuit exists in the wire harness between terminal 1 of connector B and terminal 1 of connector C.
3. CHECK FOR SHORT CIRCUIT If the wire harness is ground shorted (Scheme 43), locate the section by conducting a resistance check with the body ground (below). Check the resistance with the body ground. Disconnect connectors A and C and measure the resistance. Standard resistance (Scheme 44) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition Connector A terminal 1 - Body ground Below 1 Connector A terminal 2 - Body ground 10 k or higher HINT: Measure the resistance while lightly shaking the wire harness vertically and horizontally. If your results match the examples above, a short circuit exists between terminal 1 of connector A and terminal 1 of connector C. Disconnect connector B and measure the resistance. Standard resistance (Scheme 45) TESTER CONNECTION SPECIFIED CONDITION Tester Connection Specified Condition Connector A terminal 1 - Body ground 10 k or higher Connector B2 terminal 1 - Body ground Below 1 If the results match the examples above, a short circuit exists between terminal 1 of connector B2 and terminal 1 of connector C.
4. CHECK AND REPLACE ECU NOTE: The connector should not be disconnected from the ECU. Perform the inspection from the backside of the connector on the wire harness side. When no measuring condition is specified, perform the inspection with the engine stopped and the ignition switch ON. Check that the connectors are fully seated. Check for loose, corroded or broken wires. First, check the ECU ground circuit. If it is faulty, repair it. If it is normal, the ECU could be faulty. Temporarily replace the ECU with a normally functioning one and check if the symptoms occur. If the trouble symptoms disappear, replace the original ECU. Measure the resistance between the ECU ground terminal and body ground. Standard resistance: Below 1 Disconnect the ECU connector. Check the ground terminal on the ECU side and wire harness side for bending, corrosion or foreign matter. Lastly, check the contact pressure of the female terminals.

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See also:
• PREPARATION