TCC - Change in Diagnosis w/ECM Modification
TSB No. TS3-25 02236(R)Section Title: Drivetrain
Division: Automotive
Category: Technical
SUBJECT:
MODIFICATION OF ENGINE CONTROL MODULE (ECM)
MODEL:
SIDEKICK 2-DOOR WITH GM 3-SPEED AUTOMATIC TRANSMISSION
YEAR:
1995 AND LATER
CONDITION:
Change in diagnosis of TCC Relay Control System.
CAUSE:
Modification in the ECM
CORRECTION:
When diagnosing the TCC Relay Control System, use the testing procedures as listed in this bulletin.
REVISION:
Correction of vehicle speed designations for 8-valve and 16-valve engines.
This bulletin is to inform you of a modification in the ECM which is effective in 1995 model year vehicles matching or exceeding the VIN numbers listed below. The Torque Converter Clutch (TCC) Relay Control System in 1995 and later 2-door Sidekick Automatic Transmissions has been modified to operate through ECM control, replacing the Pressure Switch in the valve body. Because of this modification, the ECM and the diagnostic procedures related to the TCC Relay Control System have been changed. If the vehicle matches or exceeds the starting VIN numbers listed below, please use the diagnostic procedures as listed in this bulletin.
For a complete description of this modification, please see Technical Service Bulletin # TS 3-26.
STARTING VIN NUMBERS
Engine Type VIN
8-valve engine 2S3TC01C_S6415411~
16-valve engine 253TC02C_S6400001~
16-valve engine 253TA02C_S6400001~
TORQUE CONVERTER CLUTCH (TCC) RELAY
CONTROL SYSTEM (3 A/T)
This system controls the TCC relay, one of the components that controls the torque converter clutch. A circuit diagram of this system is shown in Figure 1.
The TCC solenoid valve, under the control of the A/T oil pressure switch and TCC relay, opens and closes the A/T oil passage to lock and unlock the torque converter clutch.
The ECM controls the relay using information from the following sensors:
^ Throttle Position Sensor (TPS)
^ Camshaft Position Sensor (CMP)
^ Engine Coolant Temperature Sensor (ECT)
^ Vehicle Speed Sensor (VSS).
The ECM engages the relay only under the following conditions:
^ Engine is running
^ Engine coolant temperature is above 60°C (140°F)
^ Throttle valve opening is between 6.40 and 62.5
^ Vehicle speed is higher than - 40 mph (64 km/h, 8-valve engine) or - 47 mph (75 km/h, 16-valve engine, late type ECM only).
Battery voltage is applied to the TCC solenoid valve under the following conditions:
^ The relay is ON
^ The brake pedal is released (brake pedal switch is ON)
^ The A/T oil pressure is higher than the specified pressure (the oil pressure switch is ON).
Even when the relay is ON, if the brake pedal is depressed or the A/T oil pressure is too low, the TCC solenoid valve circuit opens and voltage is not applied.
TORQUE CONVERTER CLUTCH DIAGNOSIS (LATE TYPE ECM)
ELECTRICAL CHECK
Preliminary checking procedure in Section 7B of Service Manual should be performed prior to this chart.
PARTS SUPPLY DATA