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.
On Board Diagnosis Logic
^ This is not an OBD-II self-diagnostic item.
^ Diagnostic trouble code "A/T 1ST E/BRAKING" with CONSULT-II or 13th judgement flicker without CONSULT-II is detected under the following condition.
- When TCM does not receive the proper voltage signal from the sensor.
- When TCM monitors each 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 (The sensor circuit is open or shorted.)
^ Low coast brake solenoid valve
^ ATF pressure switch 2
DTC Confirmation Procedure
NOTE: If "DTC Confirmation Procedure" has been previously conducted, always turn ignition switch "OFF" and wait at least 10 seconds before conducting the next test.
After the repair, perform the following procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Turn ignition switch to "ON" position. (Do not start engine.)
2. Select "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Start engine.
4. Maintain the following conditions for at least 2 consecutive seconds.
ENGINE SPEED: 1,200 rpm
Selector lever: "D" position
Gear position: 1st gear
5. If DTC is detected, go to "Diagnostic Procedure".
Wiring Diagram-AT-E/BRE
Diagnostic Procedure
1. CHECK INPUT SIGNALS
With CONSULT-II
1. Start engine.
2. Select "TCM INPUT SIGNALS" or "MAIN SIGNALS" in "DATA MONITOR" mode for "A/T" with CONSULT-II.
3. Accelerate vehicle in the "D" position (1st gear), and confirm the ON/OFF actuation of the "ATF PRES SW 2".
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2. CHECK HARNESS BETWEEN TCM AND A/T UNIT ASSEMBLY HARNESS CONNECTOR
1. Turn ignition switch to "OFF" position.
2. Disconnect TCM connector.
3. Check continuity between A/T unit assembly harness connector and TCM connector.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. CHECK TERMINAL CORD ASSEMBLY
1. Remove oil pan.
2. Disconnect A/T unit assembly harness connector and control valve assembly harness connector.
3. Check continuity between A/T unit assembly harness connector and control valve assembly harness connector.
4. If OK, check harness for short to ground and short to power.
5. Reinstall any part removed.
OK or NG
OK >> Replace the control valve assembly.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4. CHECK DTC
Perform "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> GO TO 5.
5. PERFORM TCM INSPECTION
1. Perform TCM input/output signal inspection.
2. If NG, recheck TCM pin terminals for damage or loose connection with harness connector.
OK or NG
OK >> INSPECTION END
NG >> Repair or replace damaged parts.