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DTC P1879: Gear Block 4th


caution
  • If there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, diagnose the CAN bus lines.
  • Whenever the ECU is replaced, ensure that the CAN bus lines are normal.

DIAGNOSTIC FUNCTION


TC-SST-ECU checks that the gear engagement is normal.

DESCRIPTIONS OF MONITOR METHODS


The engagement of the 4th gear is determined to be impossible.

MONITOR EXECUTION



MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)


Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
Sensor (The sensor below is determined to be normal)

LOGIC FLOW CHARTS (Monitor Sequence)




DTC SET CONDITIONS


Check Conditions
JUDGMENT CRITERIA

OBD-II DRIVE CYCLE PATTERN


The 4th gear is engaged.

PROBABLE CAUSES



DIAGNOSTIC PROCEDURE
Required Special Tools:
  • MB991958 Scan Tool (M.U.T.-III Sub Assembly)

    • MB991824: Vehicle Communication Interface (V.C.I.)
    • MB991827 M.U.T.-III USB Cable
    • MB991910 M.U.T.-III Main Harness A

STEP 1. Scan tool CAN bus diagnostics
Using scan tool MB991958, diagnose the CAN bus lines.

Q. Is the check result normal?
Go to Step 2.
Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting .) After repairing the CAN bus line, go to Step 2.

STEP 2. Check the fluid.

Q. Is the fluid level proper?
Go to Step 3.
Add the fluid.

STEP 3. Check whether the DTC is reset.
(1)Erase the DTC.
(2)Drive with shifted in the 4th gear.
(3)Check that the DTC is reset.

Q. Is DTC No.P1879 set?
Replace the transaxle assembly. (Refer to .)
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)