1-2 Shift Solenoid Circuit Check: Notes

The 1-2 shift solenoid is attached to valve body and is a normally open exhaust valve. PCM engages solenoid by grounding circuit No. 1222 with an internal quad-driver. The 1-2 shift solenoid is on in 1st and 4th gears, and off in 2nd and 3rd gears. When on, 1-2 shift solenoid redirects fluid to act on shift valves.

1. This test checks 1-2 shift solenoid and internal transmission wiring for short circuits.
2. This test checks for power, from the ignition through the fuse, to the shift solenoid.
3. This test ensures circuit No. 1222 is not shorted to ground.
4. This test checks ability of PCM to ground or control 1-2 shift solenoid. If bidirectional scan tester is not available, solenoid may be activated by grounding ALDL test terminal "B" with ignition on and engine off.