Today we discuss about Diagnostic process. This is part of Lesson 7 of Manual Transmission and Drivetrain.
Table of Contents
Manual Transmission and Drivetrain : Lesson 7 – Diagnostic Process
General
Objective
Upon completion of this lesson you will be able to:
! Explain the symptom-to-system-to-component-to-cause diagnostic procedure.
At a glance
Symptom-to-system-to-component-to-cause diagnostic procedure diagnosis
Diagnosis requires a complete knowledge of the system operation. As with all diagnosis, a technician must use symptoms and clues to determine the cause of a vehicle concern. To aid the technician when diagnosing vehicles, the strategies of many successful technicians have been analyzed and incorporated into a diagnostic strategy and into many service publications.
Symptom-to-system-to-component-to-cause diagnostic method
Using the Symptom-to-System-to-Component-toCause (SSCC) diagnostic routine provides you with a logical method for correcting customer concerns:
! First, confirm the “Symptom” of the customer’s concern.
! Next, determine which “System” on the vehicle could be causing the symptom.
! Once you identify the particular system, determine which “Component(s)” within that system could be the cause for the customer concern.
! After determining the faulty component(s) you should always try to identify the cause of the failure.
In some cases parts just wear out. However, in other instances something other than the failed component is responsible for the problem.
For example, if a clutch is chattering because it is oil soaked, replacing the clutch assembly will correct the chattering problem. However, if the oil leak that caused the clutch failure is not corrected at the same time the clutch will certainly fail again.
SSCC Diagram
- Symptom
- Vehicle systems
- Components
- Causes
At a glance
Workshop manual
The vehicle workshop manual contains information for diagnostic steps and checks such as: preliminary checks, verification of customer concern, special driving conditions, road tests and diagnostic pinpoint tests.
Manual transmission and drivetrain List of abbreviations
The abbreviations conform to the standard SAE J1930 except those marked with an asterisk (*).
N* Neutral
Nm* Newton-Meters
P* Park
PTO* Power Take-Off
PVH* Pulse Vacuum Hub
R* Reverse
RPM* Revolutions Per Minute
RWD* Rear-Wheel Drive
SSCC Symptom-to-System-to-Componentto-Cause
U-Joint* Universal Joint
4WD* Four-Wheel Drive
ABS* Anti-lock Brake Systems
AWD All-Wheel Drive
Countershaft* Layshaft
CPP* Clutch Pedal Position switch
CV* Constant Velocity joints
FWD* Front-Wheel Drive
IRS* Independent Rear Suspension
Kg* Kilogram
Layshaft* Countershaft
Lb-Ft* Foot-Pounds
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