P1731
DTC P1731 A/T 1ST ENGINE BRAKINGDescription
Fail-safe function to prevent sudden decrease in speed by engine brake other than at M1 position.
CONSULT-II Reference Value:
On Board Diagnosis Logic
^ This is not an OBD-II self-diagnostic item.
^ Diagnostic trouble code "P1731 A/T 1ST E/BRAKING" with CONSULT-II or 13th judgement flicker without CONSULT-II is detected under the following conditions.
- When TCM does not receive the proper voltage signal from the sensor.
- When TCM monitors each ATF pressure switch and solenoid monitor value, and detects as irregular when engine brake of 1st gear acts other than at M1 position.
Possible Cause
^ Harness or connectors
(Sensor circuit is open or shorted.)
^ Low coast brake solenoid valve
^ ATF pressure switch 2
DTC Confirmation Procedure
CAUTION:
^ Always drive vehicle at a safe speed.
^ Be careful not to rev engine into red zone on the tachometer.
NOTE: If "DTC Confirmation Procedure" has been previously preformed, 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. Turn ignition switch ON.
2. Select "SELECTION FROM MENU" in "DATA MONITOR" mode for "A/T" with CONSULT-II and check monitor "ENGINE SPEED", "MANU MODE SW" and "GEAR".
3. Touch "START".
4. Start engine.
5. Drive vehicle and maintain the following conditions for at least 2 consecutive seconds.
ENGINE SPEED: 1,200 rpm
MANU MODE SW: ON
GEAR: "1" position
6. If DTC is detected, go to AT-145, "Diagnostic Procedure".
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 "M" position (1st gear), and confirm the ON/OFF actuation of "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. Refer to AT-179, "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.
NG >> Repair or replace damaged parts.
4. CHECK DTC
Perform AT-144, "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.