Automatic Transmission Diagnostic Flow Chart

AUTOMATIC TRANSMISSION DIAGNOSTIC FLOW TABLE





Refer to the following information for the details of each step.

1. CUSTOMER COMPLAINT ANALYSIS
Record details of the problem (failure, complaint) and how it occurred as described by the customer.
For this purpose, use of such an inspection form will facilitate collecting information to the point required for proper analysis and diagnosis.

2. DIAGNOSTIC TROUBLE CODE (DTC)/FREEZE FRAME DATA CHECK, RECORD AND CLEARANCE
First, check DTC (including pending DTC). If DTC exists, print or write down DTC and freeze frame data and then clear them. DTC indicates malfunction in the system but it is not possible to know from it whether the malfunction is occurring now or it occurred in the past and normal condition has been restored. In order to know that, check symptom in question according to Step 4 and then recheck DTC according to Step 5.
Diagnosing a trouble based on the DTC in this step only or failure to clear the DTC in this step may result in an faulty diagnosis, trouble diagnosis of a normal circuit or difficulty in troubleshooting which is otherwise unnecessary.

3. and 4. VISUAL INSPECTION
As a preliminary step, be sure to perform visual check of the items that support proper function of the engine and automatic transmission.

5. TROUBLE SYMPTOM CONFIRMATION
Check trouble symptoms based on information obtained in Step 1 "Customer complaint analysis" and Step 2 "DTC/freeze frame data check".
Also, reconfirm DTC according to "DTC Confirmation Procedure" described in each "DTC Diag. Flow Table".

6. and 7. RECHECKING AND RECORD OF OTC/FREEZE FRAME DATA

8. AUTOMATIC TRANSMISSION BASIC CHECK AND SYMPTOM-TO-INSPECTION TABLE
Perform basic check of A/T according to "Automatic Transmission Basic Check Flow Table" first. When the end of the flow table has been reached, check the parts of the system suspected as a possible cause and based on symptoms appearing on the vehicle (symptoms obtained through steps of customer complaint analysis, trouble symptom confirmation and/or A/T basic check) and repair or replace faulty parts, if any.

9. DIAGNOSTIC TROUBLE CODE FLOW TABLE
Based on the DTC indicated in Step 6 and 7 locate the cause of the trouble, namely in a sensor, switch, wire harness, connector, actuator, PCM or other part and repair or replace faulty parts

10. CHECK FOR INTERMITTENT PROBLEM
Check parts where an intermittent trouble is easy to occur (e.g., wire harness, connector, etc.) and related circuit of DTC recorded in step 2.

11. FINAL CONFIRMATION TEST
Confirm that the problem symptom has gone and the vehicle is free from any abnormal conditions.
If what has been repaired is related to the DTC, clear the DTC once, perform DTC confirmation procedure and check to ensure that no DTC is indicated.

CUSTOMER PROBLEM INSPECTION FORM (EXAMPLE)














NOTE: The above form is a standard sample. It should be modified according to conditions characteristic of each market.