A/T - 4L30E Third Gear Starts
TECHNICAL BULLETIN # 248DATE 1994
TRANSMISSION: 4L30E
SUBJECT: Third gear starts
APPLICATION: ISUZU
4L30E
Third gear starts
This condition can be caused by a winter switch (if equipped) that has failed, closed. When the winter mode is selected by the driver, the computer commands third gear starts for better driveability on snow or ice (the unit will still shift to fourth gear at the appropriate speed).
If the switch fails (closed) it can continually send a winter mode signal to the computer. For a quick test of the switch, turn the key off, disconnect the winter mode switch harness connector and drive the vehicle. If the transmission returns to normal operation replace the switch. The Isuzu part number for the switch is: 8-94368-568-1.