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Home >> Toyota >> 2004 >> MR2 C56 >> Repair and Diagnosis >> Transmission >> Manual Trans >> Manual Trans Sequential - Diagnostics >> DTC P0812: Reverse Input Circuit >> Inspection Procedure

Inspection Procedure

NOTE: Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, etc. at the time of the malfunction.
  1. Check gear and shift position. 

    PREPARATION: 

    1. Turn the ignition switch ON.
    2. Connect the hand-held tester to the DLC3.

    CHECK: 

    When the shift is in N, 1, 2 and R, check the shift and select lever shaft position, shift position indicator and the value shown in the tester.

    OK: 

    1. All of them show the same value in each shift position. 

    1. OK: Go to step   6 
    2. NG: Go to next step 
  2. Check for open or short in harness and connector between shift stroke sensor and transmission control ECU, and select stroke sensor and transmission control ECU ( PROCEDURE  ). 
    1. NG: Repair or replace harness and connector. 
    2. OK: Go to next step 
  3. Inspect shift stroke sensor. 

    PREPARATION: 

    Remove the shift stroke sensor.

    CHECK: 

    Check the voltage of the shift stroke sensor.

    1. Connect 3 dry cell batteries (1.5 V) in series.
    2. Connect the battery positive (+) wire to terminal A and the battery negative (-) wire to terminal C.
    3. Measure the voltage between terminals C and B when moving the link.

    Fig 1: Checking Voltage Of Shift Stroke Sensor
    G02914031Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    1. Voltage (Power source voltage at 4.5 V): 

    POWER SOURCE VOLTAGE

    Sensor Angle (degree) Terminal (C - B) Output Voltage (V)
    44.8 4.127 - 4.306
    135.5 0.185 - 0.364

    HINT:

    Formula when the power source voltage has changed.

    (4V less than or equal to power source, less than or equal to 6V)

    POWER SOURCE VOLTAGE

    Sensor Angle (degree) Output Voltage (V)
    44.8 Power source x (0.937 +/- 0.02)
    135.5 Power source x (0.061 +/- 0.02)
    1. NG: Replace shift stroke sensor. 
    2. OK: Go to next step 
  4. Inspect select stroke sensor. 

    PREPARATION: 

    Remove the select stroke sensor.

    CHECK: 

    Check the voltage of the select stroke sensor.

    1. Connect 3 dry cell batteries (1.5 V) in series.
    2. Connect the battery positive (+) wire to terminal A and the battery negative (-) wire to terminal C.
    3. Measure the voltage between terminals C and B when moving the link.
    Fig 2: Checking Voltage Of Select Stroke Sensor
    G02914032Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    OK: 

    1. Voltage (Power source voltage at 4.5 V): 
    POWER SOURCE VOLTAGE

    Sensor Angle (degree) Terminal (C - B) Output Voltage (V)
    44.8 4.127 - 4.306
    135.5 0.185 - 0.364

    HINT:

    Formula when the power source voltage has changed.

    (4V less than or equal to power source, less than or equal to 6V)

    POWER SOURCE VOLTAGE

    Sensor Angle (degree) Output Voltage (V)
    44.8 Power source x (0.937 +/- 0.02)
    135.5 Power source x (0.061 +/- 0.02)
    1. NG: Replace select stroke sensor. 
    2. OK: Go to next step 
  5. Inspect gear shift actuator installation ( REMOVAL  ). 

    Inspect the installation condition of the shift and select lever shaft and shift actuator link.

    1. NG: Repair or replace gear shift actuator or shift and select lever shaft. 
    2. OK: Replace transmission control ECU. 
  6. Connect hand-held tester and read value of transmission reverse switch. 

    PREPARATION: 

    1. Turn the ignition switch ON.
    2. Connect the hand-held tester to the DLC3.

    CHECK: 

    Read the reverse switch value using the hand-held tester.

    OK: 

    1. Result: 
    REVERSE SWITCH VALUE

    Shift position Reverse switch value
    Neutral OFF
    R ON
    1. NG: Replace transmission control ECU. 
    2. OK: Go to next step 
  7. Check for open or short in harness and connector between transmission control ECU and reverse switch, and reverse switch and IG ( PROCEDURE  ). 
    1. NG: Repair or replace harness and connector. 
    2. OK: Go to next step 
  8. Inspect back-up light switch and back-up light switch No. 2. 

    PREPARATION: 

    Remove the back-up light switch and back-up light switch No. 2.

    CHECK: 

    Check the continuity between terminals of the switch.

    OK: 

    1. Continuity: 
    Fig 3: Checking Continuity Between Terminals Of Switch
    G02914033Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    CONTINUITY:

    Switch Position Specified Condition
    Free No continuity
    Push Continuity
    1. NG: Replace switch. 
    2. OK: Replace transmission control ECU. 
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