Diagnosis & Repair

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

Jack up the vehicle. Disconnect the park/neutral position switch connector. Check continuity between each terminal when the shift lever is moved to each position. See PARK/NEUTRAL POSITION SWITCH CONTINUITY table. Replace park/neutral position switch as necessary. If okay, go to next step.

PARK/NEUTRAL POSITION SWITCH CONTINUITY

Shift Position	Terminal No. To Continuity
P	1-3, 6-9
R	2-3
N	3-5, 6-9
D, 4	3-7
3	3-4
2, L	3-8

Connect the park/neutral position switch connector. Disconnect the shift lock control unit connector. Check continuity between each terminal of shift lock control unit connector. See SHIFT LOCK CONTROL UNIT CONTINUITY table. Replace shift lock control unit as necessary. If okay, go to next step.

SHIFT LOCK CONTROL UNIT CONTINUITY

Shift Position	Tester Connection	Specified Value
D	2-10 (AT4-NSSD)	No Continuity
4	2-10 (AT4-NSSD)	Continuity
2	3-6 (NSSL-ATL)	No Continuity
L	3-6 (NSSL-ATL)	Continuity

Connect the shift lock control unit assembly. Turn the ignition switch ON. Measure voltage between each terminal of P, N, D, 4, 3 , 2, L and R of ECM and body ground. See ECM VOLTAGE CHECK table. Ensure battery positive voltage is present at each terminal. Repair or replace harness or connector as necessary. If okay, replace ECM.

ECM VOLTAGE CHECK

Tester Connections	Shift Lever Position
P - Body Ground	P
R - Body Ground	R
N - Body Ground	N
0 - Body Ground	D & 4
4 - Body Ground	4
3 - Body Ground	3
2 - Body Ground	2 & L
L - Body Ground	L