System Description
WARNING: This page is about a different car, the 2006 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.
The ECM uses signals from the output shaft speed sensor and input speed sensor 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 TROUBLE DETECTION CONDITION
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P0761 | S3 stuck ON malfunction*1
: When the ECM directs the gearshift to switch 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)
|
|
| 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)
|
|
HINT:
- Gear positions in the event of a solenoid valve mechanical problem:GEAR POSITIONS
ECM command gearshift 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under S3 stuck ON malfunction 3rd (1) (1) *2: Actual gear position under S3 stuck OFF malfunction 3rd 4th 4th 4th 5th 6th (1) 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 POSITIONSGear position under normal conditions 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under fail safe mode when S3 stuck ON malfunction 3rd 3rd 3rd *2: Actual gear position under fail safe mode when S3 stuck OFF malfunction 3rd 4th 4th 4th 5th 6th