P1774

P1774 LOW COAST BRAKE SOLENOID





Description
- Low coast brake solenoid valve is turned ON or OFF by the TCM in response to signals sent from the trans- mission range switch, output 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-III Reference Value in Data Monitor Mode









On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "P1774" with CONSULT-III or 7th judgment flicker without CONSULT-III 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-III
1. Start the engine.
2. Select "DATA MONITOR" in "TRANSMISSION".
3. Accelerate vehicle to maintain the following conditions.

MANU MODE SW: ON
GEAR: "1" or "2" (LC/B ON/OFF)

4. Perform step 3 again.
5. Turn ignition switch OFF, then perform step 1 to 4 again.
6. Check "SELF-DIAG RESULTS" in "TRANSMISSION".
If DTC (P1774) is detected, go to P1774.
If DTC (P1772) is detected, go to P1772.

WITH GST
Follow the procedure "WITH CONSULT-III".




Diagnosis Procedure
1.CHECK INPUT SIGNALS
With CONSULT-III
1. Start engine.
2. Select in "DATA MONITOR" in "TRANSMISSION".
3. Drive vehicle in the manual mode (1GR or 2GR), and confirm the ON/OFF actuation of the "ATF PRES
SW 2" and "ON OFF SOL". P1774.
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. Main Power Supply and Ground Circuit.
OK or NG
OK - GO TO 3.
NG - Repair or replace damaged parts.
3.DETECT MALFUNCTIONING ITEM
Check A/T assembly harness connector pin terminals for damage or loose connection with harness connector.
OK or NG
OK - Replace the control valve with TCM. Service and Repair.
NG - Repair or replace damaged parts.
4.CHECK DTC
Perform P1774.
OK or NG
OK - INSPECTION END
NG - GO TO 2.