P1855

DTC P1855: Shift Fork 3 or 4 opposite direction movement

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 movement of the shift fork is normal.

DESCRIPTIONS OF MONITOR METHODS
The movements of the shift fork 3 and 4 are determined to be abnormal.

MONITOR EXECUTION
^ Continuous

MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)

Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
^ P1836: Shift fork 1 malfunction
^ P1831D: Shift fork 2 malfunction
^ P1844: Shift fork 3 malfunction
^ P184B: Shift fork 4 malfunction

Sensor (The sensor below is determined to be normal)
^ Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)

[Functional check-move opposite direction right side]





DTC SET CONDITIONS [FUNCTIONAL CHECK-MOVE OPPOSITE DIRECTION RIGHT SIDE]

Check Conditions
^ Voltage of battery: 8 V or more.
^ Voltage of battery: 16.5 V or less.
^ Engine speed: 500 r/min or more.
^ Time since above engine condition: 400 millisecond or more.
^ Shift fork 3 and 4 current gear: Neutral.
^ Shift fork 3 and 4 target direction: 0 mm (0 inch) or less.

JUDGMENT CRITERIA
Shift fork 3 and 4 position: 1.8 mm (0.071 inch) or more. (250 millisecond)

OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK-MOVE OPPOSITE DIRECTION RIGHT SIDE]
The shift fork 3 and 4 positions remain 1.8 mm (0.071 inch) or less for 250 milliseconds.

LOGIC FLOW CHARTS (Monitor Sequence)

[Functional check-move opposite direction left side]





DTC SET CONDITIONS [FUNCTIONAL CHECK-MOVE OPPOSITE DIRECTION LEFT SIDE]

Check Conditions
^ Voltage of battery: 8 V or more.
^ Voltage of battery: 16.5 V or less.
^ Engine speed: 500 r/min or more.
^ Time since above engine condition: 400 millisecond or more.
^ Shift fork 3 and 4 current gear: Neutral.
^ Shift fork 3 and 4 target direction: 0 mm (0 inch) or more.

JUDGMENT CRITERIA
^ Shift fork 3 and 4 position: -1.8 mm (-0.071 inch) or less. (250 millisecond)

OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK-MOVE OPPOSITE DIRECTION LEFT SIDE]
The shift fork 3 and 4 positions remain -1.8 mm (-0.071 inch) or more for 250 milliseconds.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU
^ Malfunction of TC-SST shift fork

DIAGNOSTIC PROCEDURE

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

Q: Is the check result normal?
YES: Go to Step 2.
NO: Repair the CAN bus lines. After repairing the CAN bus line, go to Step 2.

STEP 2. Check whether the DTC is reset.

Q: Is the DTC No. P1855 set?
YES: Replace the TC-SST assembly.
NO: Intermittent malfunction.