Contents Wiring diagrams Section: Electronic Controlled Automatic Transmission (ECT) - Diagnosis: Diagnosis All sections

PROBLEM SYMPTOMS TABLE Lexus SC II

PROBLEM SYMPTOMS TABLE

HINT

If a normal code is displayed during the DTC check but the trouble still occurs, check the circuits for each symptom in the order given in the charts on the following pages and proceed to the page given for troubleshooting.

The Matrix Chart is divided into 3 chapters.

  1. If the instruction "Proceed to next circuit inspection shown on matrix chart" is given in the flow chart for each circuit, proceed to the circuit with the next highest number in the table to continue the check.
  2. If the trouble still occurs even though there are no abnormalities in any of the other circuits, then check and replace the ECM.

CHAPTER 1: ELECTRONIC CIRCUIT MATRIX CHART

SymptomSuspect AreaSee
No up shift (A particular gear, from 1st to 4th gear, is not up-shifted)ECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No up shift (4th --> 5th)Transmission control switch circuit ECMDTC P0705 TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT) ELECTRONIC CIRCUIT INSPECTION PROCEDURE
No down shift (5th --> 4th)Transmission control switch circuit ECMCIRCUIT DESCRIPTION ELECTRONIC CIRCUIT INSPECTION PROCEDURE
No down shift (A particular gear, from 1st to 4th gear, is not up-shifted)ECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No lock upECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No lock up offECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
Shift point too high or too lowThrottle position sensor circuit PATTERN SELECT SWITCH CIRCUIT ECMPATTERN SELECT SWITCH CIRCUIT ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Up shift to 5th from 4th while shift lever is 4 positionTransmission control switch circuit ECMCIRCUIT DESCRIPTION ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Up shift to 5th from 4th while engine is coldEngine coolant temp, sensor circuit ECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No kick downECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No pattern selectPATTERN SELECT SWITCH CIRCUIT ECMPATTERN SELECT SWITCH CIRCUIT ELECTRONIC CIRCUIT INSPECTION PROCEDURE
Engine stalls when starting off or stoppingECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No kick downECMELECTRONIC CIRCUIT INSPECTION PROCEDURE
No 2nd startPATTERN SELECT SWITCH CIRCUIT ECMPATTERN SELECT SWITCH CIRCUIT ELECTRONIC CIRCUIT INSPECTION PROCEDURE

PROBLEM SYMPTOMS (CHAPTER 1: ELECTRONIC CIRCUIT MATRIX)

CHAPTER 2: ON-VEHICLE REPAIR

(*: A650E AUTOMATIC TRANSMISSION Repair Manual Pub. No. RM843U)

SymptomSuspect AreaSee
Vehicle does not move in any forward position and reverse positionsTransmission control rod Manual valve Parking lock pawl Off-vehicle repair matrix chart* *
Vehicle does not move in R positionReverse control valve Off-vehicle repair matrix chart*
Vehicle does not move in particular position or positions (Except R position)Off-vehicle repair matrix chart
No up shift (1st --> 2nd)1-2 shift valve Off-vehicle repair matrix chart*
No up shift (2nd --> 3rd)2-3 shift valve Off-vehicle repair matrix chart*
No up shift (3rd --> 4th)3-4 shift valve Off-vehicle repair matrix chart*
No up shift (4th --> 5th)4-5 shift valve Off-vehicle repair matrix chart*
No down shift (5th --> 4th)4-5 shift valve Off-vehicle repair matrix chart*
No down shift (4th --> 3rd)3-4 shift valve Off-vehicle repair matrix chart*
No down shift (3rd --> 2nd)2-3 shift valve Off-vehicle repair matrix chart*
No down shift (2nd --> 1st)1-2 shift valve Off-vehicle repair matrix chart*
No lock up or No lock up offLock up control valve Lock up relay valve Off-vehicle repair matrix chart* *
Harsh engagement (N --> D)Accumulator control valve Solenoid modulator valve C 1 accumulator Orifice control valve Off-vehicle repair matrix chart* * * *
Harsh engagement (Lock up)Lock up control valve Lock up relay valve Solenoid relay valve Off-vehicle repair matrix chart* * *
Harsh engagement (N --> R)Accumulator control valve C 2 accumulator Solenoid modulator valve Off-vehicle repair matrix chart* * *
Harsh engagement (2 --> L)Coast brake control valve*
Harsh engagement (2nd --> 3rd --> 4th --> 5th)Accumulator control valve Solenoid modulator valve* *
Harsh engagement (1st --> 2nd)Solenoid modulator valve B3 control valve B2 release control valve Solenoid relay valve Off-vehicle repair matrix chart* * * *
Harsh engagement (2nd -->3rd)Accumulator control valve Solenoid modulator valve B2 accumulator B3 control valve B2 release control valve Solenoid relay valve Off-vehicle repair matrix chart* * * * * *
Harsh engagement (3rd --> 4th)Accumulator control valve Solenoid modulator valve C2 accumulator Off-vehicle repair matrix chart* * *
Harsh engagement (4th --> 5th)Accumulator control valve Solenoid modulator valve Bo accumulator Off-vehicle repair matrix chart* * *
Harsh engagement (5th --> 4th)Accumulator control valve Solenoid modulator valve Co accumulator Off-vehicle repair matrix chart* * *
Slip or shudder (Forward and reverse)Transmission control rod Oil strainer Pressure relief valve Off-vehicle repair matrix chart* * PARK/NEUTRAL POSITION SWITCH ASSY
Slip or shudder (Particular position)Transmission control rod Off-vehicle repair matrix chartPARK/NEUTRAL POSITION SWITCH ASSY
No engine braking (1st: L position)Coast brake control valve B-4 relay valve Off-vehicle repair matrix chart* *
No engine braking (2nd: 2 position)Coast brake control valve Off-vehicle repair matrix chart*
No kick down1-2 shift valve 2-3 shift valve 3-4 shift valve* * *

PROBLEM SYMPTOMS (CHAPTER 2: ON-VEHICLE REPAIR)

CHAPTER 3: OFF-VEHICLE REPAIR

(*: A650E AUTOMATIC TRANSMISSION Repair Manual Pub. No. RM843U)

SymptomSuspect AreaSee
Vehicle does not move in any forward position and reverse positionsO/D one-way clutch (F 0 ) O/D direct clutch (C 0 ) O/D planetary gear unit Torque converter clutch* * * TORQUE CONVERTER CLUTCH AND DRIVE PLATE
Vehicle does not move in R positionCenter and rear planetary gear unit Direct clutch (C 2 ) 1st & reverse brake (B 4 ) O/D brake- (B 0 )* * * *
No up shift (1st -->2nd)2nd brake (B 3 )*
No up shift (2nd -->3rd)3rd brake (B 2 ) One-way clutch No. 1 (F 1 )* *
No up shift (3rd -->4th)Direct clutch*
No up shift (4th -->5th)O/D brake (B 0 )8
No lock up or No lock up offTorque converter clutchTORQUE CONVERTER CLUTCH AND DRIVE PLATE
Harsh engagement (N -->D)Forward clutch (C 1 ) O/D one-way clutch (F 0 ) One-way clutch No. 2 (F 2 )* * *
Harsh engagement (N -->R)Direct clutch (C 2 ) O/D brake (B 0 ) 1st & reverse brake (B 4 )* * *
Harsh engagement (1 -->2)2nd brake (B 3 )*
Harsh engagement (2 -->3)3rd brake (B 2 ) 2nd brake (B 3 ) One-way clutch No. 1 (F 1 )* * *
Harsh engagement (3 -->4)Direct clutch (C 2 )*
Harsh engagement (4 -->5th)O/D brake (B 0 ) O/D direct clutch (C 0 )* *
Harsh engagement (Lock up)Torque converter clutchTORQUE CONVERTER CLUTCH AND DRIVE PLATE
Slip or shudder (Forward and reverse: After warm-up)O/D one-way clutch (F 0 ) O/D direct clutch (C 0 ) Torque converter clutch* * TORQUE CONVERTER CLUTCH AND DRIVE PLATE
Slip or shudder (Particular position: Just after engine starts)Torque converter clutchTORQUE CONVERTER CLUTCH AND DRIVE PLATE
Slip or shudder (R position)Direct clutch (C 2 ) O/D brake (B 0 ) 1st & reverse brake (B 4 )* * *
Slip or shudder (1st)Forward clutch (C 1 ) No. 2 one-way clutch (F 2 )* *
Slip or shudder (2nd)2nd brake (B 3 )*
Slip or shudder (3rd)3rd coast brake (B 1 ) 3rd brake (B 2 ) One-way clutch No. 1 (F 1 )* * *
Slip or shudder (4th)Direct clutch*
Slip or shudder (5th)O/D brake (B 0 )*
No engine braking (1st -->4th: D position)O/D direct clutch (C 0 )*
No engine braking (1st: L position)1st & reverse brake (B 4 )*
No engine braking(2nd: 2 position) 2nd brake (B 3 )*
No engine braking(3rd: 3 position) 3rd coast brake (B 1 )*
Poor acceleration (All positions)Torque converter clutchTORQUE CONVERTER CLUTCH AND DRIVE PLATE
Poor acceleration (5th)O/D brake (B 0 ) O/D planetary gear unit* *
Engine stalls when starting off or stoppingTorque converter clutchTORQUE CONVERTER CLUTCH AND DRIVE PLATE

PROBLEM SYMPTOMS (CHAPTER 3: OFF-VEHICLE REPAIR)