Caravan AWD V6-201 3.3L (1991)
Control Module: Description and Operation
TCM Outputs
General Information
The TCM directly controls the following:
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Transmission Control Relay
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Solenoid pack
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Torque management requests to the PCM
Additionally, the TCM broadcasts the following information over the CCD Bus for use by other vehicle control systems (Indirect Outputs):
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Communication with the DRB Scan Tool for diagnostics
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Shift lever position to the BCM
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Shift lever position to the shift lever display
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Transmission oil temperature to the PCM in order to activate the cooling fans
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Vehicle speed Hard-wired to PCM and PCM sends to BCM over CCD Bus
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Limp - in Status
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Transmission Temperature
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In-gear position
NOTE: MIL request is from the PCM.
Transmission Control Relay
The instant the ignition is turned "ON," the TCM performs a self-test to determine if its internal electronic circuits are all working properly. If the
self-test results are good, then the TCM sends battery voltage to the Transmission Relay control circuit. The relay closes its internal contacts, which then
supply battery voltage to the TCM, the four solenoids and the three pressure switches in the solenoid assembly. If the TCM "sees" a problem in the
system, it turns off the power feed to the Transmission Control Relay, causing the contacts to open. A diagnostic trouble code is then stored in memory.
The Transmission Control Relay is located in various places depending on the vehicle model.
Solenoid and Pressure Switch Assembly