P1852

DTC P1852: Shift Fork 1 or 2 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 1 and 2 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
^ P183D: 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: 650 r/min or more.
^ Time since above engine condition: 1.5 seconds or more.
^ Shift fork 1 and 2 current gear: Neutral.
^ Shift fork 1 and 2 target direction: 0 mm (0 inch) or less.

JUDGMENT CRITERIA
^ Shift fork 1 and 2 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 1 and 2 positions remain 1.8 mm (0.071 inch) or less for 250 millisecond.

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: 650 r/min or more.
^ Time since above engine condition: 1.5 seconds or more.
^ Shift fork 1 and 2 current gear: Neutral.
^ Shift fork 1 and 2 target direction: 0 mm (0 inch) or more.

JUDGMENT CRITERIA
^ Shift fork 1 and 2 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 1 and 2 positions remain -1.8 mm (-0.071 inch) or more for 250 millisecond.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU
^ Malfunction of valve body

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?
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.
1) Erase the DTC,
2) With the engine idle status, operate the shift lever in the following sequence: P ->R ->D ->R ->P. (Hold each range for 1 second or more.)
3) Check that the DTC is reset.
Q: Is the DTC No. P1852 set?
YES: Replace the mechatronic assembly.
NO: Intermittent malfunction.