Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

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Scan Tool Testing and Procedures

NOTE: Use the AODE transmission tester overlay to diagnose the 4R70W transmission.

The Rotunda Transmission Tester is used to diagnosis electronically controlled transmission and is used in conjunction with the pinpoint tests. The tests should be performed in order. Installing the Rotunda Transmission Tester allows separation of the vehicle electronics from transmission electronics; refer to the Rotunda Transmission Tester manual for these tests.
- Bench Testing-Engine Off
- Resistance/Continuity Test
- Solenoid Voltage Test
- Dynamic Testing-Engine On
- EPC Solenoid
- Transmission Engagements
- Upshifts/Downshifts
- Torque Converter Clutch (TCC) Engagement
- Output Shaft Speed (OSS) Sensor
- Digital Transmission Range (TR) Sensor Testing
- Resistance/Continuity Test
- Voltage Test-Park/Neutral, Backup Lamp, and Optional Circuits