First, has code P1682 been cleared?
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Checking TCM on CCD Bus:
Use a digital volt/ohmmeter....
Disconnect and isolate negative battery cable from battery,
Refer to the schematic above,
Detach connector from the TCM,
Refer to the TCM pin out drawing below (view looking at the detached TCM connector),
Using your digital ohmmeter, measure for continuity (near 0 resistance) between pin 6 of the TCM connector and pin 11 of the Data Link Connector (DLC), Check for resistance between pin 7 of the TCM connector and pin 3 of the DLC. Any high resistance or open indicates the TCM may not be connected to the CCD Bus.
The same process can be used to check the SCI Transmit TCM wire. Measure for continuity beteen pin 14 of the TCM connector and pin 7 of the DLC. An open or high resistance reading may indicate the TCM SCI signal is not connected to the DLC (scanner).
While you're here, using your digital ohmmeter, measure for continuity beteen pin 24 of the TCM connector (TCM ground to ground point G101 on engine) and a good chassis ground (gas pedal pivot bracket mount bolt is good).
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Attach TCM connector,
Attach negative battery connector.
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Using your digital voltmeter....
Turn ignition switch to Run (engine off),
Touch positive probe of voltmeter to pin 3 of the DLC and negative probe of the voltmeter to pin 4 of the DLC. You should read about 4.5 volts. Touch the positive probe to pin 11 of the DLC and the negative probe to pin 4 of the DLC. You should read about 4.5 volts.
Voltage readings significantly out of range of the 4.5 volts may indicate a module on the CCD bus is corrupting the bus.