System Description

WARNING: This page is about a different car, the 2015 Lexus IS 250 and 2014 Lexus IS 250. However, it is still accessible from the selected car via links, so may be relevant.

The ECM uses signals from the transmission revolution sensor (SP2) and transmission revolution sensor (NT) to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
P0761	Shift Solenoid "C" Performance (Shift Solenoid Valve S3)	[S3 stuck ON malfunction1:] When the ECM directs the gearshift to change to 5th or 6th gear, the engine overruns (clutch slips). The ECM determines there is a malfunction when either of the following conditions is met. (2-trip detection logic) (a) When the ECM directs the gearshift to change to 4th gear, the actual gear is shifted to 3rd. (b) When the ECM directs the gearshift to change to 5th gear, the engine overruns (clutch slips). [S3 stuck OFF malfunction2:] Shifting to 1st, 2nd, and 3rd gears is impossible. The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic) (a) When the ECM directs the gearshift to change to 2nd gear, the actual gear is shifted to 4th. (b) When the ECM directs the gearshift to change to 6th gear, the actual gear is shifted to 6th.	[S3 stuck ON malfunction1:] Shift solenoid valve S3 remains open Shift solenoid valve SLT remains open or closed Valve body is blocked Automatic transmission (clutch, brake or gear, etc.) [S3 stuck OFF malfunction2:] Shift solenoid valve S3 remains closed Valve body is blocked Automatic transmission (clutch, brake or gear, etc.)	Comes on	DTC stored

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

MIL

Memory

P0761

Shift Solenoid "C" Performance (Shift Solenoid Valve S3)

[S3 stuck ON malfunction*1:]
When the ECM directs the gearshift to change to 5th or 6th gear, the engine overruns (clutch slips).
The ECM determines there is a malfunction when either of the following conditions is met. (2-trip detection logic)

(a) When the ECM directs the gearshift to change to 4th gear, the actual gear is shifted to 3rd.
(b) When the ECM directs the gearshift to change to 5th gear, the engine overruns (clutch slips).

[S3 stuck OFF malfunction*2:]
Shifting to 1st, 2nd, and 3rd gears is impossible.
The ECM determines there is a malfunction when the following conditions are both met. (2-trip detection logic)

(a) When the ECM directs the gearshift to change to 2nd gear, the actual gear is shifted to 4th.
(b) When the ECM directs the gearshift to change to 6th gear, the actual gear is shifted to 6th.

[S3 stuck ON malfunction*1:]

Shift solenoid valve S3 remains open
Shift solenoid valve SLT remains open or closed
Valve body is blocked
Automatic transmission (clutch, brake or gear, etc.)

[S3 stuck OFF malfunction*2:]

Shift solenoid valve S3 remains closed
Valve body is blocked
Automatic transmission (clutch, brake or gear, etc.)

Comes on

DTC stored

HINT:

Gear positions in the event of a solenoid valve mechanical problem:

ECM commanded gear	1st	2nd	3rd	4th	5th	6th
*1: Actual gear position under S3 stuck ON malfunction	1st	2nd	3rd	3rd	N*	N*
*2: Actual gear position under S3 stuck OFF malfunction	3rd	4th	4th	4th	5th	6th

N*: Neutral

Gear position during fail-safe operation:

If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below.

Gear position under normal conditions	1st	2nd	3rd	4th	5th	6th
*1: Actual gear position under fail safe mode when S3 stuck ON malfunction	1st	2nd	3rd	3rd	3rd	3rd
*2: Actual gear position under fail safe mode when S3 stuck OFF malfunction	3rd	4th	4th	4th	5th	6th