Trouble Diagnosis
TROUBLE DIAGNOSIS
DTC Inspection Priority Chart
If some DTCs are displayed at the same time, perform inspections one by one based on the following priority chart.
NOTE:
If DTC "U1000" is displayed with other DTCs, first perform the trouble diagnosis for DTC "U1000".
Fail-Safe
The TCM has an electrical fail-safe mode. This mode makes it possible to operate even if there is an error in a main electronic control input/output signal circuit.
FAIL-SAFE FUNCTION
If any malfunction occurs in a sensor or solenoid, this function controls the CVT to make driving possible.
Secondary Speed Sensor
The shift pattern is changed in accordance with throttle position when an unexpected signal is sent from the secondary speed sensor to the TCM. The overdrive-off mode is inhibited, and the transaxle is put in "D".
Primary Speed Sensor
The shift pattern is changed in accordance with throttle position and secondary speed (vehicle speed) when an unexpected signal is sent from the primary speed sensor to the TCM. The overdrive-off mode is inhibited, and the transaxle is put in "D".
Transmission Range Switch
If an unexpected signal is sent from the transmission range switch to the TCM, the transaxle is put in "D".
CVT Fluid Temperature Sensor
If an unexpected signal is sent from the CVT fluid temperature sensor to the TCM, the gear ratio in use before receiving the unexpected signal is maintained or the gear ratio is controlled to keep engine speed under 3500
rpm.
Secondary Pressure Sensor
- If an unexpected signal is sent from the secondary pressure sensor to the TCM, the secondary pressure feedback control is stopped and the offset value obtained before the non-standard condition occurs is used to control line pressure.
- If secondary pressure sensor error signal is input to TCM, secondary pressure feedback control stops, but line pressure is controlled normally.
Line Pressure Solenoid
If an unexpected signal is sent from the solenoid to the TCM, the line pressure solenoid is turned OFF to achieve the maximum fluid pressure.
Secondary Pressure Solenoid
If an unexpected signal is sent from the solenoid to the TCM, the secondary pressure solenoid is turned OFF
to achieve the maximum fluid pressure.
Torque Converter Clutch Solenoid
If an unexpected signal is sent from the solenoid to the TCM, the torque converter clutch solenoid is turned
OFF to cancel the lock-up.
Step Motor
If an unexpected signal is sent from the step motor to the TCM, the step motor coil phases "A" through "D" are all turned OFF to hold the gear ratio used right before the non-standard condition occurred.
CVT Lock-up Select Solenoid
If an unexpected signal is sent from the solenoid to the TCM, the CVT lock-up select solenoid is turned OFF to cancel the lock-up.
TCM Power Supply (Memory Back-up)
Transaxle assembly is protected by limiting the engine torque when the memory back-up power supply (for controlling) from the battery is not supplied to TCM. Normal statues is restored when turning the ignition switch
OFF to ON after the normal power supply.
How to Perform Trouble Diagnosis for Quick and Accurate Repair
INTRODUCTION
The TCM receives a signal from the vehicle speed sensor, transmission range switch and provides shift control or lock-up control via CVT solenoid valves.
The TCM also communicates with the ECM by means of a signal sent from sensing elements used with the OBD-related parts of the
CVT system for malfunction-diagnostic purposes. The TCM is capable of diagnosing malfunctioning parts while the ECM can store malfunctions in its memory.
Input and output signals must always be correct and stable in the operation of the CVT system. The CVT system must be in good operating condition and be free of valve seizure, solenoid valve malfunction, etc.
It is much more difficult to diagnose an error that occurs intermittently rather than continuously. Most intermittent errors are caused by poor electric connections or improper wiring. In this case, careful checking of suspected circuits may help prevent the replacement of good parts.
A visual check only may not find the cause of the errors. A road test with CONSULT (or GST) or a circuit tester connected should be performed. Follow the "WORK FLOW" .
Before undertaking actual checks, take a few minutes to talk with a customer who approaches with a driveability complaint. The customer can supply good information about such errors, especially intermittent ones. Find out what symptoms are present and under what conditions they occur. A "DIAGNOSTIC WORKSHEET" as shown on the example (Refer to "Diagnostic Worksheet Chart" )
should be used.
Start your diagnosis by looking for "conventional" errors first. This will help troubleshoot driveability errors on an electronically controlled engine vehicle.
Also check related Service bulletins.
WORK FLOW
A good understanding of the malfunction conditions can make troubleshooting faster and more accurate.
In general, each customer feels differently about a malfunction. It is important to fully understand the symptoms or conditions for a customer complaint.
Make good use of the two sheets provided, "Information From Customer" and "Diagnostic Worksheet Chart" , to perform the best troubleshooting possible.
Work Flow Chart
DIAGNOSTIC WORKSHEET
Information From Customer
-WHAT..... Vehicle & CVT model
-WHEN..... Date, Frequencies
-WHERE..... Road conditions
-HOW..... Operating conditions, Symptoms
Diagnostic Worksheet Chart
CVT Electrical Parts Location
Circuit Diagram
Inspections before Trouble Diagnosis
CVT FLUID CHECK
Fluid Leakage and Fluid Level Check
- Inspect for fluid leakage and check the fluid level. Checking CVT Fluid .
Fluid Condition Check
Inspect the fluid condition.
STALL TEST
Stall Test Procedure
1.Inspect the amount of engine oil. Replenish the engine oil if necessary.
2.Drive for about 10 minutes to warm up the vehicle so that the
CVT fluid temperature is 50 to 80�C (122 to 176�F). Inspect the amount of CVT fluid. Replenish if necessary.
3.Securely engage the parking brake so that the tires do not turn.
4.Install a tachometer where it can be seen by driver during test.
-It is good practice to mark the point of specified engine rpm on indicator.
5.Start engine, apply foot brake, and place selector lever in "D"
position.
6.While holding down the foot brake, gradually press down the accelerator pedal.
7.Quickly read off the stall speed, and then quickly remove your foot from the accelerator pedal.
CAUTION:
Do not hold down the accelerator pedal for more than 5 seconds during this test.
Stall speed:Stall Speed
8.Move the selector lever to the "N" position.
9.Cool down the CVT fluid.
CAUTION:
Run the engine at idle for at least 1 minute.
10.Repeat steps 6 through 9 with selector lever in "R" position.
Judgement Stall Test
LINE PRESSURE TEST
Line Pressure Test Port
Line Pressure Test Procedure
1.Inspect the amount of engine oil and replenish if necessary.
2.Drive the car for about 10 minutes to warm it up so that the CVT fluid reaches in the range of 50 to 80�C
(122 to 176�F), then inspect the amount of CVT fluid and replenish if necessary.
NOTE:
The CVT fluid temperature rises in the range of 50 - 80�C (122 - 176�F) during 10 minutes of driving.
3.After warming up CVT, remove the oil pressure detection plug and install the oil pressure gauge [special service tool: - (OTC-3492)].
CAUTION:
When using the oil pressure gauge, be sure to use the O-ring attached to the oil pressure detection plug.
4.Securely engage the parking brake so that the tires do not turn.
5.Start the engine, and then measure the line pressure at both idle and the stall speed.
CAUTION:
- Keep the brake pedal pressed all the way down during measurement.
- When measuring the line pressure at the stall speed, refer to "STALL TEST" .
6.After the measurements are complete, install the oil pressure detection plug and tighten to the specified torque below.
CAUTION:
- Do not reuse O-ring.
- Apply CVT fluid to O-ring.
Line Pressure
Judgement of Line Pressure Test
Road Test
DESCRIPTION
- The purpose of the test is to determine overall performance of CVT
and analyze causes of problems.
- The road test consists of the following three parts:
1."Check Before Engine Is Started".
2."Check at Idle".
3."Cruise Test".
- Before road test, familiarize yourself with all test procedures and items to check.
- Perform tests on all items until specified symptom is found. Troubleshoot items which check out No Good after road test.
CONSULT START PROCEDURE
- Using CONSULT, perform a cruise test and record the result.
- Print the result and ensure that shifts and lock-ups take place as per Shift Schedule.
1.Touch "DATA MONITOR" on "SELECT DIAG MODE" screen.
2.Touch "MAIN SIGNALS" to set recording condition.
3.See "Numerical Display", "Bar-chart Display" or "Line Graph Display".
4.Touch "START".
5.When performing cruise test. .
6.After finishing cruise test part, touch "RECORD".
7.Touch "STORE".
8.Touch "BACK".
9.Touch "DISPLAY".
10.Touch "PRINT".
11.Check the monitor data printed out.
Check before Engine Is Started
1. CHECK O/D OFF INDICATOR LAMP
1.Park vehicle on flat surface.
2.Move selector lever to "P" position.
3.Turn ignition switch OFF. Wait at least 5 seconds.
4.Turn ignition switch ON. (Do not start engine.)
Does O/D OFF indicator lamp come on for about 2 seconds?
YES- 1.Turn ignition switch OFF.
2.Perform self-diagnosis and note NG items.
.
3.Go to .
NO- Stop "Road Test". Go to O/D Off Indicator Lamp Does Not Come On .
Check at Idle
1. CHECK STARTING THE ENGINE
1.Park vehicle on flat surface.
2.Move selector lever to "P" or "N" position.
3.Turn ignition switch OFF.
4.Turn ignition switch START.
Is engine started?
YES- GO TO 2.
NO- Stop "Road Test". Mark the box on the, "How to Perform Trouble Diagnosis for Quick and
Accurate Repair" . Go to P" and "N" Position" .
2. CHECK STARTING THE ENGINE
1.Turn ignition switch ON.
2.Move selector lever to "D", "L" or "R" position.
3.Turn ignition switch START.
Is engine started?
YES- Stop "Road Test". Mark the box on the, "How to Perform Trouble Diagnosis for Quick and
Accurate Repair" . Go to P" and "N" Position" .
NO- GO TO 3.
3. CHECK "P" POSITION FUNCTION
1.Move selector lever to "P" position.
2.Turn ignition switch OFF.
3.Release parking brake.
4.Push vehicle forward or backward.
5.Apply parking brake.
Does vehicle move when it is pushed forward or backward?
YES- Mark the box P" Position, Vehicle Moves Forward or Backward When Pushed" on the. Continue "Road Test".
NO- GO TO 4.
4. CHECK "N" POSITION FUNCTION
1.Start engine.
2.Move selector lever to "N" position.
3.Release parking brake.
Does vehicle move forward or backward?
YES- Mark the box N" Position, Vehicle Moves" on the "How to Perform Trouble Diagnosis for Quick and Accurate Repair". Continue "Road Test".
NO- GO TO 5.
5. CHECK SHIFT SHOCK
1.Apply foot brake.
2.Move selector lever to "R" position.
Is there large shock when changing from "N" to "R" position?
YES- Mark the box:N" --> "R" Position" on the . Continue "Road Test".
NO- GO TO 6.
6. CHECK "R" POSITION FUNCTION
Release foot brake for several seconds.
Does vehicle creep backward when foot brake is released?
YES- GO TO 7.
NO- Mark the box R" Position" on the . Continue "Road Test".
7. CHECK "D", "L" POSITIONS FUNCTION
Move selector lever to "D" and "L" positions and check if vehicle creeps forward.
Does vehicle creep forward in all positions?
YES- Go to .
NO- Stop "Road Test". Mark the box on the, "How to Perform Trouble Diagnosis for Quick and
Accurate Repair" . Go to D" or "L" Position" .
Cruise Test
1. CHECK VEHICLE SPEED WHEN SHIFTING GEARS - PART 1
1.Drive vehicle for approximately 10 minutes to warm engine oil and CVT fluid up to operating temperature.
2.Park vehicle on flat surface.
3.Move selector lever to "P" position.
4.Start engine.
5.Move selector lever to "L" position.
6.Accelerate vehicle to 2/8-way throttle depressing accelerator pedal constantly.
Read vehicle speed and engine speed. .
OK or NG
OK- GO TO 2.
NG- Mark the box of, "Vehicle Speed Does Not
Change in "L" Position" on the .
Continue "Road Test".
2. CHECK VEHICLE SPEED WHEN SHIFTING GEARS - PART 2
1.Park vehicle on flat surface.
2.Move selector lever to "D" position.
3.Push overdrive control switch. (O/D OFF indicator lamp is on.)
4.Accelerate vehicle to 2/8-way throttle depressing accelerator pedal constantly.
Read vehicle speed and engine speed. .
OK or NG
OK - GO TO 3.
NG- Mark the box of, "Vehicle Speed Does Not
Change in overdrive-off mode" on the, "How to
Perform Trouble Diagnosis for Quick and Accurate
Repair" . Continue "Road Test".
3. CHECK VEHICLE SPEED WHEN SHIFTING GEARS - PART 3
1.Park vehicle on flat surface.
2.Move selector lever to "D" position.
3.Push overdrive control switch. (O/D OFF indicator lamp is off.)
4.Accelerate vehicle to 2/8-way throttle depressing accelerator pedal constantly.
Read vehicle speed and engine speed. .
OK or NG
OK- GO TO 4.
NG- Mark the box of , "Vehicle Speed Does Not
Change in "D" Position" on the .
Continue "Road Test".
4. CHECK VEHICLE SPEED WHEN SHIFTING GEARS - PART 4
1.Park vehicle on flat surface.
2.Move selector lever to "L" position.
3.Accelerate vehicle to full depression depressing accelerator pedal constantly.
Read vehicle speed and engine speed. .
OK or NG
OK- GO TO 5.
NG- Mark the box of, "Vehicle Speed Does Not
Change in "L" Position" on the .
Continue "Road Test".
5. CHECK VEHICLE SPEED WHEN SHIFTING GEARS - PART 5
1.Park vehicle on flat surface.
2.Move selector lever to "D" position.
3.Push overdrive control switch. (O/D OFF indicator lamp is on.)
4.Accelerate vehicle to full depressing depressing accelerator pedal constantly.
Read vehicle speed and engine speed. .
OK or NG
OK- GO TO 6.
NG- Mark the box of, "Vehicle Speed Does Not
Change in overdrive-off mode" on the, "How to
Perform Trouble Diagnosis for Quick and Accurate
Repair" . Continue "Road Test".
6. CHECK VEHICLE SPEED WHEN SHIFTING GEARS - PART 6
1.Park vehicle on flat surface.
2.Move selector lever to "D" position.
3.Push overdrive control switch. (O/D OFF indicator lamp is off.)
4.Accelerate vehicle to full depression depressing accelerator pedal constantly.
Read vehicle speed and engine speed. .
OK or NG
OK- GO TO 7.
NG- Mark the box of , "Vehicle Speed Does Not
Change in "D" Position" on the .
Continue "Road Test".
7. CHECK ENGINE BRAKE FUNCTION - PART 1
1.Release accelerator pedal.
2.Check engine brake. (O/D OFF indicator lamp is off.)
Does engine braking effectively reduce speed in "D" position?
YES- GO TO 8.
NO- Mark the box of Vehicle Does Not Decelerate By Engine Brake on the . Continue "Road Test".
8. CHECK ENGINE BRAKE FUNCTION - PART 2
1.Push overdrive control switch. (O/D OFF indicator lamp is on.)
2.Check engine brake.
Does engine braking effectively reduce speed in "D" position?
YES- GO TO 9.
NO- Mark the box of Vehicle Does Not Decelerate By Engine Brake on the . Continue "Road Test".
9. CHECK ENGINE BRAKE FUNCTION - PART 3
1.Move selector lever to "L" position.
2.Check engine brake.
Does engine braking effectively reduce speed in "L" position?
YES- 1.Stop the vehicle.
2.Perform self-diagnosis. .
NO- Mark the box of Vehicle Does Not Decelerate By Engine Brake on the . Then continue trouble diagnosis.
Vehicle Speed When Shifting Gears
Numerical value data are reference values.
TCM Terminal and Reference Value
TCM HARNESS CONNECTOR TERMINAL LAYOUT
TERMINALS AND REFERENCE VALUES FOR TCM
Data are reference values and are measured between each terminal and ground.
CONSULT Function (TRANSMISSION)
CONSULT can display each diagnostic item using the diagnostic test modes shown below.
FUNCTION
CONSULT REFERENCE VALUE
WORK SUPPORT MODE
Display Item List
Engine Brake Adjustment
CAUTION:
Mode of "+1""0""-1""-2""OFF" can be selected by pressing the "UP""DOWN" on CONSULT screen.
However, do not select mode other than "0" and "OFF". If the "+1" or "-1" or "-2" is selected, that might cause the irregular driveability.
Check CVT Fluid Deterioration Date
CAUTION:
Touch "CLEAR" after changing CVT fluid, and then erase "CVTF DETERIORATION DATE".
SELF-DIAGNOSTIC RESULT MODE
After performing self-diagnosis, place check marks for results on the . Reference pages are provided following the items.
Display Items List
X: Applicable-: Not applicable
DATA MONITOR MODE
Display Items List
X: Standard, -: Not applicable, : Option
Diagnosis Procedure without CONSULT
OBD-II SELF-DIAGNOSTIC PROCEDURE (WITH GST)
Generic Scan Tool Function.