Engine Controls - Code 62 or 26, Intermittent/No TCC

9222buick05

Bulletin
89-7125-9

Date
July, '89

Ref. No.
89-175-7125

Corp. Ref. No.
977125


SUBJECT:
INTERMITTENT AND/OR NO TCC SERVICE ENGINE SOON LIGHT CODE 62 OR 26


MODELS AFFECTED:
1988-89 CENTURY AND SKYLARK MODELS WITH 3T40/125C TRANSMISSIONS


BULLETIN COVERS

A condition of inoperative or no TCC [1][2]Torque Converter Clutch on a 1988 - 1989 THM 125C/HYDRA-MATIC 3T40 caused by a 2nd gear switch (338) that may be inoperative. Vehicle may exhibit intermittent service engine soon light and/or code 62 or 26 will be stored in the E.C.M.





DATE OF PRODUCTION CHANGE (Figure 1)

The 2nd gear switch has a 3-digit code stamped on top of the switch (metal side). The first 2 digits in the code represent the week in which the solenoid was built; the 3rd digit represents the year. All switches built with a number before Julian Date 179 (April 28, 1989), or 3rd digits of 7 or 8 when exposed to ambient operating temperatures may exhibit the following conditions:

1. Loose (flat blade terminals)
2. Terminals will appear blue or black in color

Inspect the torque converter clutch solenoid, third gear switch and entire wiring harness assembly for excessive heat exposure. 2nd gear switches produced after Julian Date 179 (April 28, 1989) are not affected.

SERVICE PROCEDURE

Do not attempt to repair suspect 2nd gear switches. If an inoperative 2nd gear switch is found in any THM 125C/HYDRA-MATIC 3T40, replace it with a new one.


SERVICE PARTS INFORMATION

Refer to the following part number when replacement of the solenoid assembly is necessary.

Part Number Description

8664388 Switch, 2nd Gear


Parts are currently available from GMSPO.

SERVICE MANUAL REFERENCE

Whenever servicing a 2nd gear switch on any THM 125C/HYDRA-MATIC 3T40, refer to the Unit Repair Section of your service manual.