Eldorado V8-252 4.1L (1982)
Technical Service Bulletin # 84467
Date: 840201
TCC - Code 39 Diagnostic Information
Bulletin No. T 84-46
File In Group
7
Number
94
Date
Feb. '84
SUBJECT:
DIGITAL FUEL INJECTION (DFI) CODE 39 (TORQUE CONVERTER CLUTCH) DIAGNOSIS
MODELS AFFECTED:
1982-1984 WITH HT4100 ENGINES
This bulletin provides service information to aid in diagnosing and in repairing Torque Converter Clutch (TCC) related conditions (commonly reported
as Code 39) on 1982-1984 model Cadillacs equipped with HT4100 engines.
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Section I lists the names and functions of an Torque Converter Clutch Components.
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Section II covers vehicle operating conditions required to enable (allow the operation of) TCC.
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Section III describes the events that take place when the TCC Applies.
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Section IV describes the conditions required for the Electronic Control Module (ECM) to test for Code 39.
^
Section V covers Electrical and Hydraulic Diagnosis of the TCC system.
The information provided in this bulletin is intended to supplement the information that is provided in the appropriate model year Service Information
Manuals.
I.Torque Converter Clutch Controls
Torque Converter Clutch engagement is controlled by several components. Some of these components are inputs to the ECM while others
function from output signals to activate the converter clutch. AU of these components, their locations and functions are listed below:
A.
Inputs to ECM - These switches and sensors provide the ECM with current vehicle operating conditions so that it may determine when
to apply the Torque Converter Clutch.
1.
Throttle Position Sensor (TPS) - Provides throttle position information (degrees of throttle angle) to the Electronic Control Module.
TCC is disengaged at low throttle angles to avoid a shudder during coastdown. It is located on the right side of the throttle body.
2.
Barometric Pressure Sensor (BARO) - Provides barometric (atmospheric) pressure information (measured in Kilopascals - KPA) to
the Electronic Control Module. TCC is disengaged at high altitudes for improved driveability. It is located under the right side of
the instrument panel.
3.
Coolant Temperature Sensor (CTS) - Provides engine coolant temperature information (in degrees Celsius - C) to the Electronic
Control Module. TCC engagement is delayed until the engine warms up for better cold driveability. It is located in the left front
corner of the intake manifold.
4.
Vehicle Speed Sensor or (VSS) - Provides vehicle speed information (in Miles Per Hour - MPH) to the Electronic Control Module.
TCC is only engaged at higher vehicle speeds to eliminate a chuggle that would be felt during low speed driving. It is located on the
back of the speedometer.
5.
Fourth Gear Switch - This normally closed switch opens when in fourth gear to provide an input signal to the ECM indicating
fourth gear operation. It is located near the control valve assembly.
6.
TCC Brake Release Switch - This normally closed switch located on the brake pedal bracket, opens when the brake is applied to
engage TCC. The Cruise Control brake release switch, also on the brake pedal bracket, provides an input signal to the ECM of
brake operation. The switches must be adjusted so that they open at the same time.
B.
Electronic Control Module (ECM) - Receives input signals and provides the ground circuit for the TCC solenoid when proper operating
conditions are met. It is located under the right side of the instrument panel.
C.
Outputs from ECM - These components react as a result of a command issued by the ECM.
1.
TCC Solenoid - Controls the exhaust passage for converter clutch signal off. When energized, it directs signal oil to the converter
clutch apply valve causing the valve to shift and apply the TCC. It is located near the control valve assembly.
II. TCC Enable Conditions
