EXPERTEC TSB (89-T-144)

Publication date: 1989-08-31
Reference number: 89-T-144

EXPERTEC TSB

TECHNICAL SERVICE BULLETIN

Reference Number(s): 89-T-144, Date of Issue: 08/31/89

POSSIBLE BLOWN VEH. FUSES ON - CIRCUITS/SHORTED TCC WIRING

Model(s): 1989 Oldsmobile Custom Cruiser

Bulletin No.: Oldsmobile 89-T-144

Date: 08/31/1989

BULLETIN ILLUSTRATION LIST

Fig 1: Graphic

Fig 2: Graphic

VEHICLE INFORMATION

MODELS/YEARS 1989 CUSTOM CRUISER WITH 2004R TRANSMISSION (RPO - MW9)

SERVICE INFORMATION

Service and parts information for transmission Torque Converter Clutch (TCC) solenold wiring which may exhibit a breakdown in insulation. This loss of insulation and possible short to ground may cause conditions affecting the vehicle's transmission, electrical system and engine performance. For example, the short may cause blown fuses and/or conditions such as loss of air conditioning, ECM, instrument cluster, etc.

Due to electrical design differences, each vehicle line may display unique conditions. It is also possible to have different conditions exhibited by each vehicle within a vehicle line. A short in the TCC circuit will usually blow a fuse on the circuit containing the TCC solenoid. To help determine which fuse may affect an individual model, refer to the "Diagnosis Information" section of this bulletin.

NOTE: Diagnosis information in this bulletin is not contained in any Service Manual.

DATE OF PRODUCTION CHANGE

(See Fig 1 )

Changes to the TCC solenoid wiring entered production effective May 17, 1989 (Julian Date 137) on all 1989 THM 200-4R transmissions.

SERVICE PROCEDURE

(See Fig 2 )

Perform all diagnostic procedures as listed in the applicable Service Manual for a specific electrical condition before checking the transmission. If no cause can be determined, perform the test procedures in this bulletin BEFORE removing the bottom pan of the transmission.

ELECTRICAL TESTING VEHICLE FOR A SHORT TO GROUND

Turn off ignition.
Disconnect the wiring harness from the transmission at the transmission case.
Replace the blown fuse.
Start the car and check if vehicle condition is still present.
NOTE: If the condition is still present, the TCC wiring is probably not the cause. If the condition is not present, test the TCC solenoid wiring. Testing for a Short to Ground in the TCC Solenoid Wiring
Turn off ignition.
Disconnect the wiring harness from the transmission at the transmission case.
Using a 1.5 volt self powered test light or a high impedance ohmmeter (such as Kent-Moore J 34029-A), insert one probe into terminal A of the harness connector (in the transmission case), and connect the other probe to the transmission case. Observe the test light or ohmmeter. Remove the probe from terminal A and insert it into terminal D. Observe the test light or ohmmeter.
If the test light glows or the ohmmeter reads near zero, this indicates a short to ground in either wire A or D of the TCC solenoid wiring.

NOTE: If a short to ground is detected in either wire, the TCC solenoid wiring must be replaced. DO NOT ATTEMPT TO REPAIR IT!

SERVICE PARTS INFORMATION

All service stock at GMSPO has been verified good. Refer to the Electrical Diagrams in the Transmission Diagnosis section of the appropriate Service Manual to determine which TCC solenoid wiring assembly is correct for the transmission model you are servicing.

SERVICE MANUAL REFERENCE

Whenever replacing a TCC solenoid wiring assembly, follow all procedures as outlined in the Transmission Unit Repair section of the applicable Service Manual.

Again, diagnosis information in this bulletin is NOT contained in any Service Manual.

DIAGNOSIS INFORMATION

Listed below is the fuse that may be blown if there is a short to ground in the transmission TCC solenold wiring. This assumes that each transmission contains three wires in the solenoid wiring assembly. Check the Transmission Diagnosis section of the appropriate Service Manual to determine which wiring assembly is being used.

This is not a complete list of all fuses that may blow. Vehicle design differences make it impossible to list every possible circuit configuration that may occur. Consult the electrical diagrams for the vehicle you are servicing to see if additional fuses may be affected.

Fig 3: PARTS INFORMATION TABLE

If the white wire shorts, three different conditions may occur depending on which wiring assembly is used on a particular transmission:

TCC ENABLED-This may occur if the transmission is over temperature and there is a short in the white wire between the TCC and the TCC switch.
TCC ENABLED IN SECOND-FOURTH-This may occur if there is a short between the temperature switch and the ECM.
ROUGH ENGINE-If the transmission has a fourth gear switch and there is a short between the switch and the ECM, the ECM will always receive a signal that the transmission is in fourth gear. This may affect engine performance if spark timing depends on transmission gear information.