Engine Controls - Code 62 or 26, Intermittent/No TCC
89pontiac17Bulletin Number: 89-7-38
Reference Number: 977125
Publish Date: 6/89
Subject: INTERMITTENT AND/OR NO TCC SERVICE ENGINE SOON LIGHT CODE 62 OR 26 (REPLACE Models 2ND GEAR SWITCH)
Affected: 1988-89 6000 AND GRAND AM MODELS WITH 3T40/125C
Figure 1:
BULLETIN COVERS:
A condition of inoperative or no TCC [1][2]Torque Converter Clutch on a 1988
- 1989 THM 125C/HYDRA-MATIC 3T40 is caused by a 2nd gear switch (338) that may be inoperative. The 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/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.