-
ECM checks for an open or short circuit in shift solenoid valves SL2 (1 trip detection logic)
- When solenoid is energized, duty ratio exceeds 75%
- When solenoid is not energized, duty ratio is less than 3%
| Last Modified: 4-30-2014 | 6.6 C | Doc ID: RM000000W8G00HX |
| Model Year: 2006 | Model: LX470 | Prod Date Range: [05/2005 - ] |
| Title: A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: P0778; Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2); 2006 MY LX470 [05/2005 - ] | ||
|
DTC |
P0778 |
Pressure Control Solenoid "B" Electrical (Shift Solenoid Valve SL2) |
DESCRIPTION
Shifting from 1st to 5th is performed in combination with the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2 and SR, which is controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated safely
![2006 MY LX470 [05/2005 - ]; A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: FAIL-SAFE CHART](../../../../stylegraphics/info.gif "2006 MY LX470 [05/2005 - ]; A750F AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM: FAIL-SAFE CHART")
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|
DTC No. |
DTC Detection Condition |
Trouble Area |
|---|---|---|
|
P0778 |
|
|
|
1. Reference: Inspect using an oscilloscope. Check the waveform of the ECM connector. Standard voltage: Refer to illustration.
|
|
MONITOR DESCRIPTION
This DTC indicates an open or short in the shift solenoid valve SL2 circuit. The ECM commands gear shifts by turning the shift solenoid valves ON/OFF. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem, illuminates the MIL and stores the DTC. Also, the ECM performs the fail-safe function and turns the other normal shift solenoid valves ON/OFF. In case of an open or short circuit, the ECM stops sending current to the circuit.
While driving and shifting between 4th and 5th gears, if the ECM detects an open or short in the shift solenoid valve SL2 circuit, the ECM determines that there is a malfunction
.
MONITOR STRATEGY
|
Related DTCs |
P0778: Shift solenoid valve SL2/Range check |
|
Required sensors/Components |
Shift solenoid valve SL2 |
|
Frequency of operation |
Continuous |
|
Duration |
1 sec. |
|
MIL operation |
Immediate |
|
Sequence of operation |
None |
TYPICAL ENABLING CONDITIONS
|
The monitor will run whenever this DTC is not present. |
None |
All of the following conditions are met: Condition (A) and (B)
Condition (A)
|
Battery voltage |
10 to 12 V |
|
CPU commanded duty |
Less than 75% |
|
Ignition switch |
ON |
|
Starter |
OFF |
Condition (B)
|
Battery voltage |
12 V or more |
|
Ignition switch |
ON |
|
Starter |
OFF |
TYPICAL MALFUNCTION THRESHOLDS
|
Output signal duty |
100% |
WIRING DIAGRAM
INSPECTION PROCEDURE
HINT:
The shift solenoid valve SL2 turns ON/OFF normally when the shift lever is on D:
|
ECM gear shift command |
1st |
2nd |
3rd |
4th |
5th |
|
Shift solenoid valve SL2 |
ON |
ON |
ON |
ON |
OFF |
PROCEDURE
|
1. |
INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL2) |
|
(a) Disconnect the E1 wire connector. |
|
(b) Measure the resistance of the transmission wire.
Standard resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
11 (SL2+) - 3 (SL2-) |
20°C (68°F) |
5.0 to 5.6 Ω |
|
11 (SL2+) - Body ground |
20°C (68°F) |
10 kΩ or higher |
|
3 (SL2-) - Body ground |
20°C (68°F) |
10 kΩ or higher |
| NG |
|
|
|
2. |
CHECK WIRE HARNESS (TRANSMISSION WIRE - ECM) |
|
(a) Disconnect the E7 ECM connector. |
|
(b) Measure the resistance of the wire harness side connector.
Standard resistance:
|
Tester Connection |
Condition |
Specified Condition |
|---|---|---|
|
E7-17 (SL2+) - E7-16 (SL2-) |
20°C (68°F) |
5.0 to 5.6 Ω |
|
E7-17 (SL2+) - Body ground |
20°C (68°F) |
10 kΩ or higher |
|
E7-16 (SL2-) - Body ground |
20°C (68°F) |
10 kΩ or higher |
| NG |
|
| OK |
|
|
3. |
INSPECT SHIFT SOLENOID VALVE SL2 |
|
(a) Remove the shift solenoid valve SL2. (b) Measure the resistance of the solenoid valve. Standard resistance: 5.0 to 5.6 Ωat 20°C (68°F) (c) Connect the battery's positive (+) lead to the terminal of the solenoid connector, and the negative (-) lead to the solenoid body. OK: Solenoid makes operating noise. |
|
| NG |
|
| OK |
|
|
|