Operation CHARM: Car repair manuals for everyone.

Preliminary Inspection

Preliminary Inspection
The following items must be checked prior to beginning the diagnostic procedures:

Know and Understand the Concern
In order to correctly diagnose a concern, first understand the customer complaint or condition. Customer contact may be required in order to begin to verify the concern. Understand the conditions as to when the concern occurs, for example:
- Hot or cold vehicle temperature.
- Hot or cold ambient temperature.
- Vehicle driving conditions.
- Vehicle loaded/unloaded.

After understanding when and how the concern occurs, proceed to Verification of Condition.

Verification of Condition
This provides information that must be used in both determining the actual cause of customer concerns and carrying out the appropriate procedures.
The following procedures must be used when verifying customer concerns for the transmission.

Determine Customer Concern

NOTE: Some transmission conditions can cause engine concerns. An electronic pressure control short circuit can cause engine misfiring. The torque converter clutch not disengaging will stall the engine.

Determine customer concerns relative to vehicle use and dependent driving conditions, paying attention to the following items:
- Hot or cold vehicle operating temperature.
- Hot or cold ambient temperatures.
- Type of terrain.
- Vehicle loaded/unloaded.
- City/highway driving.
- Upshift.
- Downshift.
- Coasting.
- Engagement.
- Noise/vibration-check for dependencies, either rpm dependent, vehicle speed dependent, shift dependent, gear dependent, range dependent, or temperature dependent.