Converter Lock-Up Signal From ECM

Warm engine to operating temperature. Raise vehicle and support drive wheels. Support suspension where necessary to prevent damage to drive axles.
Connect a test light to battery voltage. Touch TCC control driver terminal with test light. On some vehicles this is terminal "F" of the ALDL connector. See Fig 1 - Fig 5 . Accelerate vehicle to 45 MPH and note test light. If test light does not illuminate, problem is a faulty ECM connector or ECM.

Fig 1: Converter Clutch Schematic (2.5L "W" Body)

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Fig 2: Converter Clutch Schematic (3.1L "W" Body W/3T40 Transaxle)

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Fig 3: Converter Clutch Schematic (3.1L "W" Body W/4T60 Transaxle)

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Fig 4: Converter Clutch Schematic (3.4L "W" Body)

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Fig 5: Converter Clutch Schematic (3.8L "W" Body)

Courtesy of GENERAL MOTORS CORP.