P1774
DTC P1774 LOW COAST BRAKE SOLENOID VALVE FUNCTIONDescription
^ Low coast brake solenoid valve is turned ON or OFF by the TCM in response to signals sent from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
^ This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation.
CONSULT-II Reference Value:
On Board Diagnosis Logic
^ This is an OBD-II self-diagnostic item.
^ Diagnostic trouble code P1774 LC/B SOLENOID FNCT with CONSULT-II or 7th judgment flicker without CONSULT-II is detected under the following conditions.
- When TCM detects that actual gear ratio is irregular, and relation between gear position and condition of ATF pressure switch 2 is irregular during depressing accelerator pedal. (Other than during shift change)
- When TCM detects that relation between gear position and condition of ATF pressure switch 2 is irregular during releasing accelerator pedal. (Other than during shift change)
Possible Cause
^ Harness or connectors.
(Solenoid and switch circuits are open or shorted.)
^ Low coast brake solenoid valve.
^ ATF pressure switch 2.
DTC Confirmation Procedure
CAUTION: Always drive vehicle at a safe speed.
NOTE: If DTC Confirmation Procedure has been previously performed, always turn ignition switch OFF and wait at least 10 seconds before performing the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine.
2. Accelerate vehicle to maintain the following conditions.
MANU MODE SW: ON
GEAR: 1 or 2 (LC/B ON/OFF)
3. Perform step 2 again.
4. Turn ignition switch OFF, then perform step 1 to 3 again.
5. Check SELF-DIAG RESULTS mode for A/T with CONSULT-II.
If DTC (P1774) is detected, refer to AT-161, "Diagnostic Procedure".
If DTC (P1772) is detected, go to AT-159, "Diagnostic Procedure". P1772
WITH GST
Follow the procedure WITH CONSULT-II.
Diagnostic Procedure
1. CHECK INPUT SIGNALS
With CONSULT-II
1. Start the engine.
2. Select SELECTION FROM MENU in DATA MONITOR mode for A/T with CONSULT-II.
3. Drive vehicle in the manual mode (1st or 2nd gear), and confirm the ON/OFF actuation of the ATF PRES SW 2 and ON OFF SOL.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK TCM POWER SUPPLY AND GROUND CIRCUIT
Check TCM power supply and ground circuit.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. DETECT MALFUNCTIONING ITEM
Check the following.
^ A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> Replace control valve with TCM.
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform DTC Confirmation Procedure. Refer to AT-160, "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.