IN−24 − INTRODUCTION HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS 1. CUSTOMER PROBLEM ANALYSIS In troubleshooting, the problem symptoms must be confirmed accurately and all preconceptions must be cleared away in order to give an accurate judgment. To ascertain just what the problem symptoms are, it is extremely important to ask the customer about the problem and the conditions at the time it occurred. Important Point in the Problem Analysis: The following 5 items are important points in the problem analysis. Past problems which are thought to be unrelated and the repair history, etc.
may also help in some cases, so as much information as possible should be gathered and its relationship with the problem symptoms should be correctly ascertained for reference in troubleshooting. A customer problem analysis table is provided in Diagnostics section for each system for your use. What −−−−− Vehicle model, system name When −−−−− Date, time, occurrence frequency Where −−−−− Road conditions Under what conditions? −−−−− Running conditions, driving conditions, weather conditions How did it happen? −−−−− Problem symptoms Important Points in the Customer Problem Analysis (Sample) Engine control system check sheet.
CUSTOMER PROBLEM ANALYSIS CHECK ENGINE CONTROL SYSTEM Check Sheet Inspector’s Name Data Problem Constant Sometimes ( times per day/month) 24 Author : Date: Customer’s Name Model and Model Year Driver’s Name Frame No. Data Vehicle Brought in Engine Model License No.
Odometer Reading km miles Problem Symptoms Engine does not Start Engine does not crank No initial combustion No complete combustion Difficult to Start Engine cranks slowly Other Poor Idling Incorrect first idle Idling rpm is abnormal High ( rpm) Low ( rpm) Rough idling Other Poor Drive ability Hesitation Back fire Muffler explosion (after−fire) Surging Knocking Other Engine Stall Soon after starting After accelerator pedal depressed After accelerator pedal released During A/C operation Shifting from N to D Other Others