Engine Diagnostic Flow Chart

Step 1 - 11:

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.

STEP 2. DIAGNOSTIC TROUBLE CODE (DTC)/FREEZE FRAME DATA CHECK
First, check DTC, referring to "DIAGNOSTIC TROUBLE CODE CHECK". If DTC is indicated, record DTC and freeze frame data.

After that clear DTC referring to "DIAGNOSTIC TROUBLE CODE CLEARANCE". DTC indicates malfunction that occurred in the system but does not indicate whether it exists now or it occurred in the past and the normal condition has been restored now. To check which case applies, check the symptom in question according to Step 5 and recheck DTC according to Step 6, 7.

Attempt to diagnose a trouble based on DTC in this step only or failure to clear the DTC (including pending DTC) in this step will lead to incorrect diagnosis, trouble diagnosis of a normal circuit or difficulty in troubleshooting.

NOTE:
- If any DTC P0461 (Fuel level sensor circuit performance problem) is indicated in this step, perform visual inspection according to Step 3 and then proceed to DTC P0461 Flow Table.
- For Air vehicle, if only DTC P0705, P0715, P0720, P0741, P0743, P0751, P0753, P0756, P0758, or P1875 is indicated in this step, proceed to "DIAGNOSIS" in Transmission Control Systems.




STEP 3. and 4. VISUAL INSPECTION
Be sure to perform visual check of the following items that support proper function of the engine.

STEP 5. TROUBLE SYMPTOM CONFIRMATION
Based on information obtained in Step 1 "CUSTOMER COMPLAINT ANALYSIS" and Step 2 "DTC/FREEZE FRAME DATA CHECK", confirm trouble symptoms. Also, reconfirm DTC according to "DTC CONFIRMATION PROCEDURE" described in each "DTC FLOW TABLE".

STEP 6. AND 7. RECHECKING AND RECORD OF DTC
Refer to "DTC Check" for checking procedure.

STEP 8. ENGINE BASIC INSPECTION AND ENGINE DIAGNOSIS TABLE
Perform basic engine check according to the "ENGINE BASIC INSPECTION FLOW TABLE" first. When the end of the flow table has been reached, check the parts of the system suspected as a possible cause referring to "ENGINE DIAGNOSIS TABLE" and based on symptoms appearing on the vehicle (symptoms obtained through steps of customer complaint analysis, trouble symptom confirmation and/or basic engine check) and repair or replace faulty parts, if any.

Step 1 - 10:

Engine Basic Inspection Flow Table

STEP 9. TROUBLESHOOTING FOR DTC
Based on the DTC indicated in Step 6 or 7 and referring to the applicable DTC diag. flow table, locate the cause of the trouble, namely in a sensor, switch, wire harness, connector, actuator, ECM (PCM) or other part and repair or replace faulty parts.

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

STEP 11. FINAL CONFIRMATION TEST
Confirm that the problem symptom has gone and the engine 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 confirm that no malfunction DTC (a normal code) is indicated.