Toyota Celica 1986-1993 Repair Guide

Troubleshooting

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Many problems in ABS systems are caused by poor connections, improper tire pressures, etc. Various checks and suggestions are given to avoid a large repair bill, if possible. However, some diagnostic procedures require specialized training and knowledge in order to repair the vehicle safely, properly and least expensively. A problem that cannot be identified using the information given should be referred to a qualified technician.

SYSTEM PRECAUTIONS





Certain components within the ABS system are not intended to be serviced or repaired individually. Only those components with removal and installation procedures should be serviced.
 
Do NOT use rubber hoses or other parts not specifically specified for the ABS system. When using repair kits, replace all parts included in the kit. Partial or incorrect repair may lead to functional problems and require the replacement of components.
 
Lubricate rubber parts with clean, fresh brake fluid to ease assembly. Do NOT use lubricated shop air to clean parts; damage to rubber components may result.
 
Use only dot 3 brake fluid from an unopened container.
 
If any hydraulic component or line is removed or replaced, it may be necessary to bleed the entire system.
 
A clean repair area is essential. Always clean the reservoir and cap thoroughly before removing the cap. The slightest amount of dirt in the fluid may plug an orifice and impair the system function. Perform repairs after components have been thoroughly cleaned; use only denatured alcohol to clean components. Do NOT allow ABS components to come into contact with any substance containing mineral oil; this includes used shop rags.
 
The ABS ECU is a microprocessor similar to other computer units in the vehicle. Insure that the ignition switch is OFF before removing or installing controller harnesses. Avoid static electricity discharge at or near the controller.
 
If any arc welding is to be done on the vehicle, the ABS controller should be disconnected before welding operations begin.
 
If the vehicle is to be baked after paint repairs, disconnect and remove the ABS ECU from the vehicle.
 

INITIAL CHECKS



Visual Inspection

Before diagnosing an apparent ABS problem, make absolutely certain that the normal braking system is in correct working order. Many common brake problems (dragging parking brake, leakage, etc.) will affect the ABS system. A visual check of specific system components may reveal problems creating an apparent ABS malfunction. Performing this inspection may reveal a simple failure.

  1. Start the engine and drive a speed over 4 mph. Listen carefully for actuator operation as the vehicle passes 4 mph. If the brake is not applied, the controller cycles each solenoid and operates the pump motor briefly as an initial system check.
  2.  
  3. Return the vehicle to the workplace and turn the ignition switch OFF . Check battery condition; approximately 12 volts is required to operate the system.
  4.  
  5. Turn the ignition switch ON and check that the dashboard warning lamp (ABS or antilock) comes on for 3-4 seconds. If the lamp does not come on, repair the fuse, bulb or wiring.
  6.  
  7. Inspect the tire pressures; they must be approximately equal for the system to operate correctly.
  8.  
  9. Inspect the brake fluid level in the reservoir.
  10.  
  11. Inspect brake lines, hoses, master cylinder assembly and brake calipers for leakage.
  12.  
  13. Visually check brake lines and hoses for excessive wear, heat damage, punctures, contact with other parts, missing clips or holders, blockage or crimping.
  14.  
  15. Check the calipers or wheel cylinders for rust or corrosion. Check for proper sliding action if applicable.
  16.  
  17. Check the caliper and wheel cylinder pistons for freedom of motion during application and release.
  18.  
  19. Inspect the wheel speed sensors for proper mounting and connections.
  20.  
  21. Inspect the sensor wheels for broken teeth or poor mounting.
  22.  
  23. Inspect the wheels and tires on the vehicle. They must be of the same size and type to generate accurate speed signals.
  24.  
  25. Confirm the fault occurrence with the operator. Certain driver induced faults, such as not releasing the parking brake fully, will set a fault code and trigger the dash warning light(s). Excessive wheel spin on low-traction surfaces, high speed acceleration or riding the brake pedal may also set fault codes and trigger a warning lamp. These induced faults are not system failures but examples of vehicle performance outside the parameters of the control unit
  26.  
  27. Many system shut-downs are due to loss of sensor signals to or from the controller. The most common cause is not a failed sensor but a loose, corroded or dirty connector. Incorrect adjustment of the wheel speed sensor will cause a loss of wheel speed signal. Check harness and component connectors carefully.
  28.  

READING DIAGNOSTIC CODES



If a malfunction occurs during normal driving, the system will identify the problem and the computer will assign and store a fault code for the fault(s). The dashboard warning lamp will be illuminated to inform the driver that a fault has been found.

During diagnostics, the system will transmit this type of stored code(s) by flashing the dashboard warning lamp. If two or more codes are stored, they will be displayed from lowest number to highest, regardless of the order of occurrence. The system does not display the diagnostic codes while the vehicle is running.

Procedure
1988-89 VEHICLES
  1. Turn the ignition switch ON .
  2.  
  3. On 2WD vehicles, remove the relay bracket bolt to gain access to the check connector.
  4.  
  5. Disconnect the service connector.
  6.  



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Fig. Fig. 1 Disconnecting service connector for reading ABS codes1988-89 2WD Celica shown



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Fig. Fig. 2 Disconnecting service connector for reading ABS codes1988-89 4WD Celica shown

  1. If a fault code has been set, the dashboard warning lamp will begin to blink 4 seconds later. The number of flashes corresponds to the first digit of a 2-digit code; after a 1.5 second pause, the second digit is transmitted. If a second code is stored, it will be displayed after a 2.5 second pause. Once all codes have been displayed, the entire series will repeat after a 4 second pause.
  2.  
  3. If no codes have been stored, the warning lamp will flash continuously every 1 / 2 second with no variation.
  4.  
  5. Turn the ignition switch OFF .
  6.  
  7. Check or have the system repaired as indicated by the fault code.
  8.  



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Fig. Fig. 3 Example of Codes 11 and 23 occurring togetherCelica



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Fig. Fig. 4 Normal ABS light functionCelica

  1. After repairs are completed, clear the codes from the memory. If the battery is disconnected during repairs, the ABS ECU memory will be erased of all stored codes.
  2.  
  3. Reconnect the check connector.
  4.  
  5. Turn the ignition switch ON and check that the dashboard warning lamp (ABS or antilock) comes on for 3-4 seconds.
  6.  
  7. Install the relay bracket with the bolt on 2wd models.
  8.  

1990-93 VEHICLES
  1. With the ignition switch ON , disconnect the service connector.
  2.  



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Fig. Fig. 5 Disconnecting service connector1990-93 Celica shown



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Fig. Fig. 6 Connecting check terminals for reading ABS codes1990-93 Celica shown



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Fig. Fig. 7 ABS light normal condition and Code 231990-93 Celica shown

  1. Use a jumper wire to connect terminals Tc and E1 of the check connector.
  2.  
  3. If a fault code has been set, the dashboard warning lamp will begin to blink 4 seconds later. The number of flashes corresponds to the first digit of a 2-digit code; after a 1.5 second pause, the second digit is transmitted. If a second code is stored, it will be displayed after a 2.5 second pause. Once all codes have been displayed, the entire series will repeat after a 4 second pause.
  4.  
  5. If no codes have been stored, the warning lamp will flash continuously every 1 / 2 second with no variation.
  6.  
  7. Turn the ignition switch OFF .
  8.  
  9. Check or have the system repaired as indicated by the fault code.
  10.  
  11. After repairs are completed, clear the codes from the memory. If the battery is disconnected during repairs, the controller memory will be erased of all stored codes.
  12.  
  13. Remove the jumper wire and reconnect the service connector at the actuator.
  14.  
  15. Turn the ignition switch ON and check that the dashboard warning lamp (ABS or antilock) comes on for 3-4 seconds.
  16.  



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Fig. Fig. 8 ABS Trouble Codes

CLEARING DIGNOSTIC CODES



Procedure
1988-89 VEHICLES
  1. Turn the ignition switch ON .
  2.  
  3. On 2WD vehicles, remove the relay bracket bolt and pull out the relay for access to the check connector.
  4.  
  5. Disconnect the check connector.
  6.  
  7. Keep the vehicle stopped.
  8.  
  9. Clear the ABS diagnostic codes by depressing the brake pedal 8 or more times within 3 seconds.
  10.  
  11. Check that the warning lamp shows a normal pattern.
  12.  
  13. Reconnect the check connector.
  14.  
  15. Check that the warning lamp goes off.
  16.  
  17. Reinstall the relay bracket on 2wd models.
  18.  

1990-93 VEHICLES
  1. Turn the ignition switch ON .
  2.  
  3. Connect terminals Tc and E1 with a jumper wire.
  4.  
  5. Keep the vehicle stopped.
  6.  
  7. Clear the ABS diagnostic codes by depressing the brake pedal 8 or more times within 3 seconds.
  8.  
  9. Check that the warning lamp shows a normal pattern.
  10.  
  11. Disconnect the jumper wire. The dash warning lamp should go out.
  12.  

FRONT SPEED SENSOR



Testing
  1. Remove the screw and/or bolt from the pipe clamp of the wire harness, if equipped.
  2.  
  3. Disconnect the speed sensor connector.
  4.  
  5. Measure the resistance between the terminals of the sensor.
  6.  
  7. The resistance should be 850-1300 ohms for 1988-89 models and 800-1300 ohms for 1990-93 models. If not within specifications, replace the sensor.
  8.  
  9. Check that there is no continuity between each terminal and the sensor body. If there is, replace the sensor.
  10.  
  11. Reconnect the sensor connector.
  12.  



Click image to see an enlarged view

Fig. Fig. 9 Checking front speed sensor resistance1988-89 Celica shown

REAR SPEED SENSOR



Testing
  1. On 1988-89 4WD models and on 1990-93 models, remove the rear seat cushion.
  2.  
  3. Disconnect the speed sensor connector.
  4.  
  5. Measure the resistance between the terminals of the sensor.
  6.  
  7. The resistance should be:

    1988-89 models: 850-1300 ohms
     
    1990-93 2WD models: 1100-1700 ohms
     
    1990-93 4WD models: 800-1500 ohms
     

  8.  
  9. If not within specifications, replace the sensor.
  10.  
  11. Check that there is no continuity between each terminal and the sensor body. If there is, replace the sensor.
  12.  
  13. Reconnect the sensor connector.
  14.  

CONTROL RELAYS



Testing
1988-89 MODELS WITH 2WD
  1. Check the continuity of the motor relay circuit. There should be continuity between terminals 5 and 7. There should be no continuity between terminals 1 and 3. If so, replace the relay.
  2.  
  3. Apply battery voltage to terminal 5 and connect terminal 7 to battery ground. There should be continuity between terminals 1 and 3. If not, replace the relay.
  4.  
  5. Check the continuity of the solenoid relay. There should be continuity between terminals 6 and 7 as well as between terminals 2 and 8 or 10. There should be no continuity between terminals 2 and 4.
  6.  
  7. Connect the positive lead of the ohmmeter to terminal 2 and the negative lead to terminal 9. There should be continuity. Switch the leads. There should not be continuity.
  8.  
  9. Apply battery voltage to terminal 6 and connect terminal 7 to battery ground. There should be continuity between terminals 2 and 4.
  10.  
  11. All checks must be met. If any check reveals a fault, the relay must be replaced.
  12.  



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Fig. Fig. 1 0Checking motor relay1988-89 Celica shown



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Fig. Fig. 1 1Checking solenoid relay1988-89 Celica shown

1988-89 MODELS WITH 4WD
  1. Remove the 2 control relays from the actuator.
  2.  
  3. Check the continuity of the motor relay circuit. There should be continuity between terminals 1 and 2. There should be no continuity between terminals 3 and 4, or between terminals 1 and 4. If incorrect, replace the relay.
  4.  
  5. Apply battery voltage to terminal 1 and connect terminal 2 to battery ground. There should be continuity between terminals 3 and 4, but not between terminals 1 and 4. If incorrect, replace the relay.
  6.  
  7. Check the continuity of the solenoid relay. There should be continuity between terminals 1 and 3 as well as between terminals 2 and 4. There should be no continuity between terminals 4 and 5.
  8.  
  9. Apply battery voltage to terminal 1 and connect terminal 3 to battery ground. There should be continuity between terminals 4 and 5, but not between terminals 2 and 4.
  10.  
  11. All checks must be met. If any check reveals a fault, the relay must be replaced.
  12.  



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Fig. Fig. 1 2Solenoid and motor relays1990-91 Celica shown



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Fig. Fig. 1 3Checking motor relay1990-91 Celica shown



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Fig. Fig. 1 4Checking solenoid relay1990-91 Celica shown

1990-93 MODELS
  1. Disconnect the control relay.
  2.  
  3. Check the continuity and operation, probing the proper terminals.
  4.  
  5. If not as specified, replace the control relay.
  6.  



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Fig. Fig. 1 6Checking motor and solenoid relays1992-93 Celica shown

 
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