Toyota Previa 1991-1997 Repair Information

Reading Codes

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2TZ-FE ENGINE



Engine

See Figures 1 through 4

All models equipped with the 1991-95 2TZ-FE engines utilize the OBD I system.

  1. Make sure the battery voltage is at least 11 volts.
  2.  
  3. Make sure the throttle valve is fully closed.
  4.  
  5. Place the gear shift lever in Neutral. Turn all accessories off.
  6.  
  7. The engine should be at normal operating temperature.
  8.  
  9. Using a jumper wire, connect terminals TE1 and E1 of the Data Link Connector 1 (DLC1).
  10.  

Some aftermarket companies have a scanner which just slides into the DLC1

  1. Turn the ignition switch ON , but do not start the engine. Read the diagnostic code by the counting the number of flashes of the malfunction indicator lamp.
  2.  



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Fig. Fig. 1: Count the number of flashes on the CHECK ENGINE light

The check connector is located under the drivers seat.

  1. Codes will flash in numerical order. If no faults are stored, the lamp flashes continuously every 1 / 4 second. This is sometimes called the Normal or System Clear signal.
  2.  



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Fig. Fig. 2: A normal system operation will illuminate the light every 1/4 second

  1. The light will blink a number of time equal to the malfunction code indication as follows:
    1. Between the first and second digit, 1.5 seconds.
    2.  
    3. Betweeen codes, 2.5 seconds.
    4.  
    5. Between sets of codes 4.5 seconds.
    6.  

  2.  



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Fig. Fig. 3: Diagnostic code example of codes 13 and 21-2TZ-FE engine

  1. The code series will be repeated as long as the check connector terminals TE1 and E1 are connected. In the event that there many be more than one trouble code, indication will begin from the small value and continue to the larger in order.
  2.  
  3. After the diagnosis check, turn the ignition OFF and remove the jumper wire.
    1. Diagnaotic codes 25, 26, 27 and 71 use 2 trip detection logic. With this logic, when a malfunction is first detected, it is temporarily stored in the ECM memory. If the same symptom is detected again during the second drive test, it causes the CHECK warning light to illuminate. The 2 trip repeats the same mode a 2nd time.
    2.  

  4.  

The ignition switch must be turned

OFF between the 1st and 2nd time. In the test mode, the CHECK engine light illuminates the 1st time a malfunction is detected.



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Fig. Fig. 4: A "2 trip" diagnostic code example-2TZ-FE engine

  1. Compare the codes found to the applicable diagnostic code chart. If necessary, refer to the individual component tests in this section. If the component tests are OK, test the wire harness and connectors for shorts, opens and poor connections.
  2.  
  3. After diagnosis is complete, remove the jumper wire.
  4.  

Automatic Transmission

See Figure 5

  1. Turn the ignition switch and Over Drive (O/D) switch to the ON position, but do not start the engine.
  2.  

Warning and diagnostic codes can be read only when the O/D switch is on. If it is off, the overdrive off light will be lit continuously and not blink.

  1. Using a jumper wire, connect terminals TE1 and E1 of the DLC1.
  2.  
  3. Read the diagnostic code as indicated by the number of times the O/D off light flashes
  4.  



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Fig. Fig. 5: Read the number of times the O/D light flashes to determine the codes

  1. If the system is operating normally, the light will flash 2 times per second.
  2.  
  3. In the even that there is a malfunction, the light will flash 1.5 times per second. The number of blinks will equal the first number then, after 1.5 seconds the second number will flash a code. If there are more than two or more codes, there will be 2.5 seconds between each code.
  4.  

In the event of several trouble codes occurring simultaneously, indication will begin from the smaller value and continue to the larger.

  1. Remove the jumper wire.
  2.  

2TZ-FZE ENGINE



Engine and Automatic Transmission

See Figure 6

All 1994-97 2TZ-FZE engines are equipped with OBD II.

These models require the use of the Toyota's hand held scan tool or an equivalent OBD II compliant scan tool.

  1. Prepare the scan tool according to the manufacturers instructions.
  2.  
  3. Connect the OBD II scan tool, to the DLC3 in the fuse box located in the center upper portion of the instrument panel.
  4.  



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Fig. Fig. 6: The DLC3 is located in the fuse box at the center upper portion of the instrument panel

When the diagnosis system is switched from the normal mode to the check mode, it erases all Diagnostic Trouble Codes (DTC) and freeze frame data recorded. Before switching modes, always check the DTC and freeze frame data and write them down.

  1. Turn the ignition switch to the ON and switch the OBD II scan tool switch on.
  2.  
  3. Use the OBD II scan tool to check the DTC and freeze frame data. Write them down.
  4.  
  5. Compare the codes found to the applicable diagnostic code chart. If necessary, refer to the individual component tests in this section. If the component tests are OK, test the wire harness and connectors for shorts, opens and poor connections.
  6.  

 
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