Initial Inspection

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

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

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

Verify the Condition
This provides information that must be used in both determining the actual cause of customer concerns and carrying out the appropriate procedures.

Line Pressure Relief Valve
The solenoid body assembly contains an over-pressurization relief valve that will limit the line pressure through the (PC-A) solenoid and feedback to the pump main regulator valve. The LPC relief valve controls line pressure spikes when cold. If this valve fails you may see concerns with the filter found in the solenoid body assembly.

Transmission Range (TR-P) Sensor Assembly
The transmission range (TR-P) sensor assembly is an internally mounted sensor that includes the detent spring, rooster comb and bracket, located next to the solenoid body. The sensor is non adjustable and is not serviced independently. The TR-P sensor contains electronic circuitry that provides the PCM a fixed frequency at a duty cycle for each of the various positions of the manual lever (PARK, REVERSE, NEUTRAL, DRIVE, M3, M2 and M1) to the PCM. The PCM uses the TR-P sensor signal for engine functions (start, reverse lamps) and for line pressure control, shift scheduling and TCC operation.
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.
- Vehicles equipped with Power Take-Off (PTO), the PTO must be turned off.