Code No. P1731: 1st Engine Brake Detection


DIAGNOSIS CODE SET CONDITIONS


With the mode other than sport mode and with the accelerator angle is smaller than 6/8, the correlation between the lock-up and low-reverse brake linear solenoid valve control current and the low-reverse brake pressure switch ON/OFF is abnormal.

PROBABLE CAUSES



DIAGNOSIS PROCEDURE

STEP 1. Check the diagnosis code.
Check that P0988 (Low-reverse brake pressure switch) is set.

Q. Is the diagnosis code set?
Check and repair the relevant diagnosis code system.
Go to Step 2.

STEP 2. Check the diagnosis code.
Check that the diagnosis code other than P1731 (1st engine brake detection) is set.

Q. Is the diagnosis code set?
Check and repair the relevant diagnosis code system.
Go to Step 3.

STEP 3. Check the A/T fluid properties.
Check the status of the A/T fluid properties (smell, colour, fouling).

  • Black: A/T inside damage, seizure
  • Milky: Water intrusion

Q. Is the check result normal?
Go to Step 4.
Remove the A/T from the vehicle, then check and repair the inside.

STEP 4. Check the A/T fluid level.

Q. Is the check result normal?
Go to Step 5.
Adjust the A/T fluid level, and then go to Step 5.

STEP 5. Check the wiring harness, connector, and sensor signal.

  • Check the wiring harness and connectors of the low-clutch pressure switch and low-reverse brake pressure switch.
  • Check the signals of A/T-ECU connector PGB1 terminal (output shaft speed sensor) and the PGA1 terminal (input shaft speed sensor).
    Refer to .

Q. Is the check result normal?
Go to Step 6.
Repair or replace the failure section.

STEP 6. Hydraulic pressure test
Refer to .

Q. Is the check result normal?
Go to Step 7.
Remove the A/T from the vehicle, then check and repair the inside.

STEP 7. Erase the diagnosis code, and drive the vehicle for a while.
Check that the normal code is displayed.

Q. Is the check result normal?
The procedure is complete.
Return to Step 1.