How to Diagnose By Symptoms

SYMPTOM RELATED DIAGNOSTIC PROCEDURE

Introduction
Most of the fuel and emission control system is electrically controlled, often making it difficult to diagnose problems in the system, especially intermittent problems.

Before undertaking actual checks, take a few minutes to talk with a customer who approaches with a driveability complaint. The customer is often a good source of information on such problems, especially intermittent ones. Through talks with the customer, one can find out what the symptoms are and under what conditions they occur.

Work Flow:

Work Flow

Diagnostic Symptom Index:

Diagnostic Symptom Index

Symptom Diagnosis Charts

Description: Further describes the symptom. Confirm that the chart addresses the actual symptom before beginning troubleshooting.
Troubleshooting hints: This describes the possible point of malfunction.
Step: This shows the order of troubleshooting. Proceed with troubleshooting as indicated.
Check: This describes an inspection to determine the malfunction of parts quickly.
Remedy: This recommends the appropriate action to take as a result (Yes/No) of the check.

Diagnostic Symptom Index:

Diagnostic Symptom Index






Driveability definitions
Stumble: Mild jerking during acceleration.
Hesitation: Delay in increase in engine speed occurring just after the accelerator pedal is depressed.
Surge: Continuous soft jerking during cruise.