Work Flow
INTRODUCTION
The TCM receives signals from the vehicle speed sensor and transmission range switch. Then it provides shift control or lock-up control via CVT solenoid valves.
The TCM also communicates with the ECM by means of signals 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 a malfunction that occurs intermittently rather than continuously. Most intermittent malfunctions 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 malfunctions. A road test with CONSULT (or GST) or a circuit tester connected should be performed. Follow the "DETAILED 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 malfunctions, especially intermittent ones. Find out what symptoms are present and under what conditions they occur. A "Diagnostic Work Sheet" as shown on the example (Refer to TM-6) should be used.
Start your diagnosis by looking for "conventional" malfunctions first.
This will help troubleshoot driveability malfunctions on an electronically controlled engine vehicle.
Also check related Service Bulletins.
DETAILED FLOW
Get the detailed information from the customer about the symptom (the condition and the environment when the incident/malfunction occurred) using the diagnosis work sheet. Refer to TM-6, "Diagnostic Work Sheet".
2.CHECK SYMPTOM 1
Check the following items based on the information obtained from the customer.
3.CHECK DTC
4.PERFORM DIAGNOSTIC PROCEDURE
Perform "Diagnostic Procedure" for the displayed DTC. Repair detected items.
5.PERFORM DTC CONFIRMATION PROCEDURE
Perform "DTC CONFIRMATION PROCEDURE" for the displayed DTC.
6.CHECK SYMPTOM 2
Confirm the symptom described by the customer.
7.ROAD TEST
Perform "ROAD TEST". Refer to TM-164, "Description".
8.CHECK SYMPTOM 3
Confirm the symptom described by the customer.
Diagnostic Work Sheet
INFORMATION FROM CUSTOMER
KEY POINTS
DIAGNOSTIC WORK SHEET
Headlamp (HI) circuit
Description
The IPDM E/R (intelligent power distribution module engine room) controls the
headlamp high relay based on inputs from the BCM over the CAN communication
lines. When the headlamp high relay is energized, power flows through fuses
48 and 49, located in the IPDM E/R. Power then flow ...
Automatic air conditioner system
System Diagram
CONTROL SYSTEM
The control system consists of input sensors, switches, the A/C auto amp.
(microcomputer) and outputs. The
relationship of these components is as shown in the figure below:
System Description
CONTROL OPERATION
Display
The operation status of the HVAC system ...
TCS
System Diagram
System Description
Traction Control System is a function that electronically controls
engine torque and brake fluid pressure to
ensure the optimum slippage ratio at drive wheels by computing wheel speed
signals from 4 wheel sensors.
When ABS actuator and electric u ...