Lexus IS250 · Service Manual TRANSMISSION

P0976

Diagnostic trouble codes

DESCRIPTION

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in either of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.) Fail safe function (Click here).
DTC No.
 DTC Detection Condition
 Trouble Area
P0976
 ECM detects short in solenoid valve S2 circuit 2 times when solenoid valve S2 is operated (1-trip detection logic)
  1. Short in shift solenoid valve S2 circuit
  2. Shift solenoid valve S2
  3. ECM
P0977
 ECM detects open in solenoid valve S2 circuit 2 times when solenoid valve S2 is not operated (1-trip detection logic)
  1. Open in shift solenoid valve S2 circuit
  2. Shift solenoid valve S2
  3. ECM

MONITOR DESCRIPTION

These DTCs indicate an open or short in the shift solenoid valve S2 circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. When the shift solenoid valve S2 is on, if resistance is 8 Ω or less, the ECM determines there is a short in the shift solenoid valve S2 circuit.
When the shift solenoid valve S2 is off, if resistance is 100 kΩ or more, the ECM determines there is an open in the shift solenoid valve S2 circuit (Click here).

WIRING DIAGRAM

C110585E42

INSPECTION PROCEDURE

HINT:
  1. The shift solenoid valve S2 is turned on/off normally when the shift lever is in the D position:
    ECM command gearshift
    		 1st
    		 2nd
    		 3rd
    		 4th
    		 5th
    		 6th
    Shift solenoid valve S2
    		 ON
    		 ON
    		 OFF
    		 OFF
    		 OFF
    		 ON


1. INSPECT TRANSMISSION WIRE (S2)

  1. C110342E71
    Disconnect the transmission wire connector from the transmission.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    20°C (68°F)
    15 - Body ground
    		 11 to 15 Ω



NG
Go to step 3
OK


2. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

  1. C106186E50
    Connect the transmission connector to the transmission.

  1. Disconnect the connector from the ECM.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    20°C (68°F)
    E4-18 (S2) - Body ground
    		 11 to 15 Ω



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE ECM

3. INSPECT SHIFT SOLENOID VALVE S2

  1. C106204E04
    Remove the shift solenoid valve S2.

  1. Measure the resistance according to the value(s) in the table below.

    Standard resistance:
    Tester Connection
    		 Specified Condition
    20°C (68°F)
    Solenoid Connector (S2) - Solenoid Body (S2)
    		 11 to 15 Ω

  1. Connect positive (+) lead to the terminal of solenoid connector, negative (-) lead to the solenoid body.

    OK:
    The solenoid makes an operating sound.



 NG
REPLACE SHIFT SOLENOID VALVE S2
OK

REPAIR OR REPLACE TRANSMISSION WIRE


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