Shift Solenoid "B" Circuit Check
4L80-E AUTOMATIC TRANSMISSIONShift Solenoid "B" Diagnostic Chart:
Shift Solenoid "B" Circuit:
Circuit Description:
The shift solenoids are used inside the valve body to control spool valves which determine the transmission gear.
Fused ignition is supplied to solenoid "B".
The PCM/TCM will engage "B" by grounding CKT 1223 to energize the solenoid.
Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This procedure checks shift solenoid "B" and the internal transmission wiring for shorts.
2. This block checks for power to shift solenoid "B" from the ignition through the transmission fuse.
3. Test three verifies that CKT 1223 is not shorted to ground.
4. This test checks the ability of the PCM/TCM to ground or control shift solenoid "B".
5. The final test verifies that CKT 1223 is not shorted to ground.
Diagnostic Aids:
Check all connections, especially those at the transmission pass-thru connector. - Intermittent Malfunctions