GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 1999 🢒 GMC P42 Commercial Chassis 🢒 Transmission/Transaxle 🢒 Automatic Transmission - 4L80-E 🢒 First and Fourth Gear Only - D4

First and Fourth Gear Only

Checks

Cause

1-2 Solenoid (313)
    • Stuck On
    • Pinched wire to ground

1-2 Shift Valve (314)

Stuck

Quad Driver Module

Failed

Check the VCM/PCM for current DTCs