Automatic Transaxle - Diagnostics: Diagnosis Scion xA I

HOW TO PROCEED WITH TROUBLESHOOTING

The hand-held tester can be used at step 3 , 4 , 6 , 9 .

1. Vehicle Brought to Workshop
2. Customer Problem Analysis (See «CUSTOMER PROBLEM ANALYSIS CHECK»(ref-204126-S33935003572005110800000) )
3. Connect the OBD II scan tool or hand-held tester to DLC3
4. Check and Clear DTC and Freeze Frame Data (See «DTC CHECK/CLEAR»(ref-204126-S03114955872005110800000) )
5. Visual Inspection
6. Setting the Check Mode Diagnosis (See «CHECK MODE PROCEDURE»(ref-204126-S18617366912005110800000) )
7. Problem Symptom Confirmation (See «ROAD TEST»(ref-204126-S01150387902005110800000) ) Symptom does not occur: Go to step 8 Symptom occur: Go to step 9
8. Symptom Simulation (See «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-203959-S29160773122005110700000) )
9. DTC Check (See «DTC CHECK/CLEAR»(ref-204126-S03114955872005110800000) ) DTC is not output: Go to step 10 DTC is output: Go to step 18
10. Basic Inspection (See «ON-VEHICLE INSPECTION»(ref-180037-S41574788402005072000000) AUTOMATIC TRANSAXLE FLUID (ATM), «ADJUSTMENT»(ref-180037-S19460798602005072000000) PARK/NEUTRAL POSITION SWITCH ASSY (ATM) & «ADJUSTMENT»(ref-180037-S41297120202005072000000) FLOOR SHIFT ASSY (ATM)) NG : Go to step 20 OK : Go to next step.
11. Mechanical System Test (See «MECHANICAL SYSTEM TESTS»(ref-204126-S42038945362005110800000) ) NG : Go to step 17 OK : Go to next step.
12. Hydraulic Test (See «HYDRAULIC TEST»(ref-204126-S19004885742005110800000) ) NG : Go to step 17 OK : Go to next step.
13. Manual Shifting Test (See «MANUAL SHIFTING TEST»(ref-204126-S24022853362005110800000) ) NG : Go to step 15 OK : Go to next step.
14. Problem Symptoms Table Chapter 1 (See «PROBLEM SYMPTOMS TABLE»(ref-204126-S35877874562005110800000) ) NG : Go to step 19 OK : Go to next step.
15. Problem Symptoms Table Chapter 2 (See «PROBLEM SYMPTOMS TABLE»(ref-204126-S35877874562005110800000) ) NG : Go to step 17 OK : Go to next step.
16. Problem Symptoms Table Chapter 3 (See «PROBLEM SYMPTOMS TABLE»(ref-204126-S35877874562005110800000) ) NG : Go to next step.
17. Part Inspection Go to step 20
18. DTC Chart (See «DIAGNOSTIC TROUBLE CODE CHART»(ref-204126-S16227445632005110800000) )
19. Circuit Inspection
20. Identification of Problem
21. Repair
22. Confirmation Test End

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1. Description When troubleshooting OBD II vehicles, the only difference from the usual troubleshooting procedure is that you need to connect an OBD II scan tool complying with SAE J1987 or a hand-held tester to the vehicle, and read off various data output from the vehicle's ECM. OBD II regulations require that the vehicle's on-board computer illuminate the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in the computer itself or in the drive system components which affect the vehicle emissions. In addition to the MIL illuminating when a malfunction is detected, the applicable DTCs prescribed by SAE J2012 are recorded in the ECM memory (See «DIAGNOSTIC TROUBLE CODE CHART»(ref-204126-S16227445632005110800000) ). If the malfunction does not occur in 3 consecutive trips, the MIL goes off but the DTCs remain in the ECM memory. To check the DTCs, connect the OBD II scan tool or hand-held tester to the DLC3 of the vehicle. The OBD II scan tool or hand-held tester also enables you to erase the DTCs and check freeze frame data and various forms of engine data (For instruction book). The DTCs include SAE controlled codes and Manufacturer controlled codes. SAE controlled codes must be set as prescribed by the SAE, while Manufacturer controlled codes can be set freely by a manufacturer within the prescribed limits (See «DIAGNOSTIC TROUBLE CODE CHART»(ref-204126-S16227445632005110800000) ). The diagnosis system operates in the normal mode during the normal vehicle use, and also has a check mode for technicians to simulate malfunction symptoms and perform troubleshooting. Most DTCs use 2 trip detection logic (*1) to prevent erroneous detection. By switching the ECM to the check mode when troubleshooting, the technician can cause the MIL to illuminate for a malfunction that is only detected once or momentarily. (hand-held tester). *1: 2 trip detection logic: When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory. If the same malfunction is detected again during the second test drive, this second detection causes the MIL to illuminate.
2. Inspect the DLC3. The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of DLC3 complies with SAE J1962 and matches the ISO 9141-2 format. SPECIFIED CONDITION Tester connection Condition Specified Condition 7 (Bus (+) Line) - 5 (Signal Ground) During Communication Pulse Generation 4 (Chassis Ground) - Body Always 1 ohms Or Less 5 (Signal Ground) - Body Always 1 ohms Or Less 16 (B+) - Body Always 9 to 14 V NOTE: If your display shows UNABLE TO CONNECT TO VEHICLE when you have connected the cable of the OBD II scan tool or hand-held tester to the DLC3, turned the ignition switch to the ON position and operated the scan tool, there is a problem on the vehicle side or tool side. If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle. If the communication is still impossible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.
3. Measure the battery voltage. Battery Voltage: 11 to 14 V If voltage is below 11 V, recharge the battery before proceeding.
4. Check the MIL. The MIL comes on when the ignition switch is turned to the ON position and the engine is not running. NOTE: If the MIL does not light up, troubleshoot the combination meter. When the engine is started, the MIL should go off. If the lamp remains on, it means that the diagnosis system has detected a malfunction or abnormality in the system.

Scheme 216

1. DTC CHECK (NORMAL MODE) NOTE: Hand-held tester only: When the diagnostic system is switched from the normal mode to the check mode, all the DTCs and freeze frame data recorded in the normal mode will be erased. So before switching modes, always check the DTCs and freeze frame data, and note them down. Checking DTCs using the OBD II scan tool or hand-held tester. Turn the ignition switch off. Connect the OBD II scan tool or hand-held tester to DLC3. Turn the ignition switch to the ON position. Use the OBD II scan tool or hand-held tester to check the DTCs and freeze frame data and note them down (For operating instructions, see the OBD II scan tool's instruction book). See «DIAGNOSTIC TROUBLE CODE CHART»(ref-204126-S16227445632005110800000) to confirm the details of the DTCs. NOTE: When simulating symptoms with an OBD II scan tool (excluding hand-held tester) to check the DTCs, use the normal mode. For codes on the DTCs chart subject to "2 trip detection logic", turn the ignition switch off after the symptom is simulated once. Then repeat the simulation process again. When the problem has been simulated twice, the MIL is indicated on the instrument panel and DTCs are recorded in the ECM.
2. DTC CLEAR When using the OBD II scan tool or hand-held tester: Clearing the DTCs. Connect the OBD II scan tool or hand-held tester to the DLC3. Turn the ignition switch to the ON position. When operating the OBD II scan tool (complying with SAE J1978) or hand-held tester to erase the codes, the DTCs and freeze frame data will be erased. (See the OBD II scan tool's instruction book for operating instructions.) When not using the OBD II scan tool or hand-held tester: Clearing the DTCs. Disconnecting the battery terminal or remove the EFI and ETCS fuses from the engine room J/B for 60 seconds or more.

Scheme 217

Scheme 218

1. DTC CHECK (CHECK MODE) NOTE: Hand-held tester only: Compared to the normal mode, the check mode has more sensing ability to detect malfunctions. Furthermore, the same diagnostic items which are detected in the normal mode can also be detected in the check mode. Procedure for Check Mode using the hand-held tester. Check the initial conditions. Battery positive voltage 11 V or more Throttle valve fully closed Transaxle in the P or N position A/C switch is off Turn the ignition switch off. Connect the hand-held tester to the DLC3. Turn the ignition switch to the ON position. Switch the hand-held tester from the normal mode to the check mode (Check that the MIL flashes). NOTE: If the hand-held tester switches the ECM from the normal mode to the check mode or vice-versa, or if the ignition switch is turned from the ON position to the ACC or LOCK position during the check mode, the DTC and freeze frame data will be erased. Start the engine (MIL goes off after the engine starts). Simulate the conditions of the malfunction described by the customer. NOTE: Leave the ignition switch in the ON position until you have checked the DTCs, etc. After simulating malfunction conditions, use the hand-held tester diagnosis selector to check the DTCs and freeze frame data, etc. NOTE: Be sure not to turn the ignition switch off, as turning it off switches the diagnosis system from the check mode to the normal mode, which erases all the DTCs, etc. After checking the DTC, inspect the applicable circuit.
2. DTC CLEAR When using the OBD II scan tool or hand-held tester: Clearing the DTCs. Connect the OBD II scan tool or hand-held tester to the DLC3. Turn the ignition switch to the ON position. When operating the OBD II scan tool (complying with SAE J1978) or hand-held tester to erase the codes, the DTCs and freeze frame data will be erased. (See the OBD II scan tool's instruction book for operating instructions.) When not using the OBD II scan tool or hand-held tester: Clearing the DTCs. Disconnecting the battery terminal or remove the EFI and ETCS fuses from the engine room J/B for 60 seconds or more.

ROAD TEST

1. PROBLEM SYMPTOM CONFIRMATION Taking into consideration the results of the customer problem analysis, try to reproduce the symptoms of the trouble. If the problem is that the transaxle does not shift up, shift down, or the shift point is too high or too low conduct the following road test referring to the automatic shift schedule and simulate the problem symptoms.
2. PERFORM ROAD TEST NOTE: Conduct the test at normal operating ATF temperature 50 to 80 °C (122 to 176 °F). D position test Shift into the D position and fully depress the accelerator pedal and check the following points: Check up-shift operation. Check that 1 --> 2, 2 --> 3 and 3 --> O/D up-shift takes place, and that the shift points conform to the automatic shift schedule (See «SERVICE DATA»(ref-204109-S12152124722005110800000) ). NOTE: O/D Gear Up-shift Prohibition Control Coolant temp. is 60 °C (140 °F) or less. ATF temp. is 10 °C (68 °F) or less. O/D and 3rd Gear Lock-up Prohibition Control Brake pedal is depressed. Accelerator pedal is released. Coolant temp. is 60 °C (140 °F) or less. 3rd Gear Lock-up Prohibition Control O/D main switch off (O/D ON) Check for shift shock and slip. Check for shock and slip at the 1 --> 2, 2 --> 3 and 3 --> O/D up-shift. Check for abnormal noises and vibration. Run in D position lock up or O/D gear and check for abnormal noises and vibration. NOTE: The check for the cause of abnormal noises and vibration must be done very thoroughly as it could also be sure to loss of balance in the differential, torque converter, etc. Check kick-down operation. Check that the possible kick-down vehicle speed limits for 2nd to 1st, 3rd to 2nd, O/D to 3rd kickdowns conform to those indicated on the automatic shift schedule while driving through all gears with the shift lever in the D position (See «SERVICE DATA»(ref-204109-S12152124722005110800000) ). Check for abnormal shock and slip at kick-down. Check the lock up mechanism. Drive in D position O/D gear, at a steady speed (lock up ON) of about 60 km/h (37 mph). Lightly depress the accelerator pedal and check that the engine speed does not change abruptly. If there is a big jump in engine speed, there is no lock up. 2 position test Shift into the 2 position and fully depress the accelerator pedal and check the following points: Check up-shift operation. Check that the 1 --> 2 up-shift takes place and that the shift point conforms to the automatic shift schedule (See «SERVICE DATA»(ref-204109-S12152124722005110800000) ). NOTE: There is no O/D up-shift and lock up in the 2 position. Check engine braking. While running in the 2 position and 2nd gear, release the accelerator pedal and check the engine braking effect. Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift. L position test Shift into the L position and fully depress the accelerator pedal and check the following points: Check no up-shift. While running in the L position, check that there is no up-shift to 2nd gear. Check engine braking. While running in the L position, release the accelerator pedal and check the engine braking effect. Check for abnormal noises during acceleration and deceleration. R position test Shift into the R position and fully depress the accelerator pedal and check for slipping. CAUTION: Before conducting this test ensure that the test area is free from people and obstruction. P position test Stop the vehicle on a grade (more than 5°), shift into the P position and release the parking brake. Check that the vehicle does not move.

DATA LIST/ACTIVE TEST

1. DATA LIST NOTE: According to the DATA LIST displayed by the OBD II scan tool or hand-held tester, you can read the value of the switch, sensor, actuator and so on without parts removal. Reading the DATA LIST as the first step of troubleshooting is one method to shorten labor time. Warm up the engine. Turn the ignition switch off. Connect the OBD II scan tool or hand-held tester to the DLC3. Turn the ignition switch to the ON position. According to the display on tester, read the "DATA LIST". NORMAL CONDITION Item Measurement Item/Display (Position) Normal Condition Diagnostic Note STOP LIGHT SW Stop Light SW Status/ON Or OFF Brake Pedal Is Depressed: ON Brake Pedal Is Released: OFF - PNP SW [NSW] PNP SW Status/ON or OFF Shift Lever Position Is; P Or N:ON Except P Or N: OFF The Shift Lever Position And These Values Are Different, There Are Failures Of The PNP Switch Or Shift Cable Adjustment. NOTE: When the failure still occurs even after adjusting these parts, See «DTC P0705 TRANSMISSION RANGE SENSOR CIRCUIT MALFUNCTION (PRNDL INPUT)»(ref-204126-S35766236942005110800000) REVERSE PNP SW Status/ON or OFF Shift Lever Position Is; R:ON Except R: OFF DRIVE PNP SW Status/ON or OFF Shift Lever Position Is; D:ON Except D: OFF 2ND PNP SW Status/ON or OFF Shift Lever Position Is; 2: ON Except 2: OFF LOW PNP SW Status/ON or OFF Shift Lever Position Is; LON Except L: OFF SHIFT Actual Gear position/ 1st, 2nd, 3rd, 4th (O/D) Shift Lever Position Is; L: 1st 2: 1st or 2nd D (O/D OFF): 1st, 2nd or 3rd D (O/D ON): 1st, 2nd, 3rd or 4th (O/D) - LOCK UP SOL Lock Up Solenoid Status/ON or OFF Lock Up: ON Except Lock Up: OFF - SOLENOID (SLT) Shift Solenoid SLT Status/ON or OFF IG SW ON: ON - OVERDRV CUT SW1 O/D SW Status/ON or OFF IG SW ON: ON "DOWN ARROW" O/D SW Push: OFF "DOWN ARROW" O/D SW Push: ON
2. ACTIVE TEST NOTE: Performing the ACTIVE TEST using the hand-held tester allows the relay, VSV, actuator and so on to operate without parts removal. Performing the ACTIVE TEST as the first step of troubleshooting is one method to shorten labor time. It is possible to display the DATA LIST during the ACTIVE TEST. Warm up the engine. Turn the ignition switch off. Connect the hand-held tester to the DLC3. Turn the ignition switch to the ON position. According to the display on tester, perform the "ACTIVE TEST". ACTIVE TEST Item Test Details Diagnostic Note SHIFT [Test Details] Operate The Shift Solenoid Valve And Set The Each Shift Position By Your-Self. [Vehicle Condition] Less than 50 km/h (31 mph) [Others] Press --> Button: Shift Up Press <-- Button: Shift Down Possible To Check The Operation Of The Shift Solenoid Valves. LOCK UP [Test Details] Control The Shift Solenoid Sl To Set The ATM To The Lock-Up Condition. [Vehicle Condition] Vehicle Speed: 58 km/h (36 mph) or more Possible To Check The SL Operation. TIMING SOL [Test Details] Operate The Shift Solenoid ST. [Vehicle Condition] Vehicle Stopped. IDL:ON Possible To Check The ST Operation. LINE PRESS UP (1) [Test Details] Operate The Shift Solenoid SLT And Raise The Line Pressure. [Vehicle Condition] Vehicle Stopped. IDL:ON [Others] OFF: Line Pressure Up. ON: No Action (Normal Operation) - (1) "LINE PRESS UP" In The ACTIVE TEST Is Performed To Check The Line Pressure Changes By Connecting The SST To The Automatic Transaxle, Which Is Used In The HYDRAULIC TEST As Well. NOTE: The pressure values in ACTIVE TEST and HYDRAULIC TEST are different from each other.

DIAGNOSTIC TROUBLE CODE CHART

If a DTC is displayed during the DTC check, check the circuit listed in the table below and proceed to the page given.

* : "FILLED CIRCLE" ... MIL light up

DIAGNOSTIC TROUBLE CODE

PROBLEM SYMPTOMS TABLE

DTC INDEX

Note. 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.

CIRCUIT DESCRIPTION

The park/neutral position switch detects the shift lever position and sends signals to the ECM.

CIRCUIT DESCRIPTION

The ATF temperature sensor converts the fluid temperature into a resistance value which is input into the ECM.

CIRCUIT DESCRIPTION

The ATF temperature sensor converts the fluid temperature into a resistance value which is input into the ECM.

CIRCUIT DESCRIPTION

This sensor detects the rotation speed of the input turbine. By comparing the input turbine speed signal (NT) with the counter gear speed sensor signal (NC), the ECM detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions. Thus, providing smooth gear shift.

CIRCUIT DESCRIPTION

The purpose of this circuit is to prevent the engine from stalling while driving in lock up condition, when brakes are suddenly applied.

When the brake pedal is depressed, this switch sends a signals to the ECM. Then the ECM cancels the operation of the lock up clutch while braking is in progress.

CIRCUIT DESCRIPTION

Shift solenoid valve ST is switched ON-OFF by a signal from ECM so that let in or out timing of 2nd brake is adjusted by operating orifice control valve. Therefore, shift solenoid valve ST operates when letting in or out reverse clutch.

If it is broken, the shift shock becomes big.

CIRCUIT DESCRIPTION

Shifting from 1st to O/D is performed in combination with ON and OFF of the shift solenoid valve S1 and S2 controlled by ECM. If an open or short circuit occurs in either of the solenoid valves, the ECM controls the remaining normal solenoid valve to allow the vehicle to be operated smoothly (Fail safe function).

Fail safe function

If either of the solenoid valve circuits develops an open or short, the ECM turns the other solenoid valve ON and OFF to shift to the gear positions shown in the table below. The ECM also turns the shift solenoid valve ST OFF at the same time. If both solenoids malfunction, hydraulic control cannot be performed electronically and must be done manually.

Manual shifting as shown in the above table must be done (In the case of a short circuit, the ECM stops sending current to the short circuit solenoid).

CIRCUIT DESCRIPTION

X: Malfunctions

CIRCUIT DESCRIPTION MALFUNCTIONS

See DTC P0973 SHIFT SOLENOID "A" CONTROL CIRCUIT LOW (SHIFT SOLENOID VALVE S1), DTC P0974 SHIFT SOLENOID "A" CONTROL CIRCUIT HIGH (SHIFT SOLENOID VALVE S1) .

CIRCUIT DESCRIPTION

The throttle pressure that is applied to the primary regulator valve (which modulates the line pressure) causes the solenoid valve SLT, under electronic control, to precisely and minutely modulate and generate the line pressure according the extent of the accelerator pedal depressed or the output of engine power.

Scheme 219

This controls the line pressure and provides smooth shifting. Upon receiving a signal of the throttle valve opening angle, the ECM controls the line pressure by sending a predetermined duty ratio to the solenoid valve, modulating the line pressure and generating throttle pressure.

Note. The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then Duty Ratio=A/ (A+B) x 100 (%). (Scheme 220)

Scheme 220

CIRCUIT DESCRIPTION

The shift solenoid valve SL is turned "ON" and "OFF" by signals from the ECM in order to control the hydraulic pressure operation, the lock up relay valve, which then the controls operation of the lock up clutch.

Fail safe function

If the ECM detects a malfunction, it turns the shift solenoid valve SL OFF.

CIRCUIT DESCRIPTION

The O/D main switch (transmission control switch) is a momentary type switch. When pressing the O/D main switch, the O/D OFF indicator light lights up and the ECM prohibits shifting into O/D, and when pressing it once again, the O/D OFF indicator light goes off and the ECM allows shifting into O/D. Turning the IG switch OFF will reset the O/D OFF indicator light.

Scheme 221

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1. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BODY GROUND) Disconnect the transmission control switch connector of shift lever assy. Measure the resistance according to the value (s) in the table below. Standard: SPECIFIED CONDITION Tester Connection Specified Condition 4 - Body ground Below 1 ohms NG : REPAIR OR REPLACE HARNESS OR CONNECTOR (See «ELECTRONIC CIRCUIT INSPECTION PROCEDURE»(ref-203959-S10482953642005110700000) ) OK : Go to next step.
2. INSPECT TRANSMISSION CONTROL SWITCH Measure the resistance according to the value (s) in the table below. Standard: SPECIFIED CONDITION Switch Condition Tester Connection Specified Condition Press continuously transmission control switch 2 - 4 Below 1 ohms Release transmission control switch 10 kohms or higher NG : REPLACE TRANSMISSION CONTROL SWITCH OK : Go to next step.
3. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM) Connect the transmission control switch connector of shift lever assy. Disconnect the ECM connector. Measure the resistance according to the value (s) in the table below. Standard: SPECIFIED CONDITION Switch Condition Tester Connection Specified Condition Press continuously transmission control switch E5 - 29 (ODMS) - Body ground Below 1 ohms Release transmission control switch 10 kohms or higher NG : REPAIR OR REPLACE HARNESS OR CONNECTOR (See «ELECTRONIC CIRCUIT INSPECTION PROCEDURE»(ref-203959-S10482953642005110700000) ) OK : PROCEED TO NEXT CIRCUIT INSPECTION SHOWN ON PROBLEM SYMPTOMS TABLE (See «PROBLEM SYMPTOMS TABLE»(ref-204126-S35877874562005110800000) )