Lock-Up & Overdrive Controls (1986 1/2 Pickup 4-CYL & L4N71B)

1. Torque converter lock-up and overdrive functions are control by a Lock-Up Control Unit (LCU). The LCU is electrically connected to an Electronic Concentrated Control System (ECCS), an Electronic Fuel Injection (EFI) control unit and various solenoids and switches.
2. LCU will activate or deactivate lock-up under predetermined conditions, through signals sent to it by the various components. A Diagnostic Sub-Harness (KV319K0010 J34270), is needed for checking voltage and continuity between LCU and main harness. Sub-harness is attached between LCU and main harness, located under passenger front seat.
3. Use appropriate testing chart for problem noted under TROUBLE SHOOTING  in this article.

Fig 1: No. 1 Chart - No Lock-Up (Pickup With Z24i)

Fig 2: No. 2 Chart - No Shift O/D Gear (Pickup With Z24i)

Fig 3: No. 3 Chart - Shifting High & Low (Pickup With Z24i)

Fig 4: No. 4 Chart - No Kickdown (Pickup With Z24i)

Fig 5: No. 5 Chart - Kickdown Occurs At High Speed (Pickup With Z24i)

Fig 6: No. 6 Chart - No Lock-Up (Pickup With VG30i)

Fig 7: No. 7 Chart - No Shifting (Pickup With VG30i)

Fig 8: No. 8 Chart - Shifting Too High Or Too Low (Pickup With VG30i)

Fig 9: No. 9 Chart - No Shift Overdrive Gear (Pickup With VG30i)

Fig 10: No. 10 Chart - Shift Schedule Will Not Change (Pickup With VG30i)

Fig 11: No. 11 Chart - No Kickdown (Pickup With VG30i)