P184B
DTC P184B: Shift Fork 4 MalfunctionCAUTION
^ 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 4 is normal.
DESCRIPTIONS OF MONITOR METHODS
The movement of the shift fork 4 is 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)
^ P1844: Shift fork 3 malfunction
Sensor (The sensor below is determined to be normal)
^ Not applicable
LOGIC FLOW CHARTS (Monitor Sequence) [Functional check - blocked]
DTC SET CONDITIONS [FUNCTIONAL CHECK - BLOCKED]
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.
^ Common high side 1 voltage: 7 V or more.
^ Common high side 3 voltage: 7 V or more.
JUDGMENT CRITERIA
^ Shift fork operation time: Shift fork operation time (threshold value) or more. (immediately)
^ Shift fork operation time (threshold value): Equal the maximum allowed time x Coefficient. (immediately)
OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK - BLOCKED]
The shift fork operation time is threshold value or less.
LOGIC FLOW CHARTS (Monitor Sequence) [Functional check - Neutral]
DTC SET CONDITIONS [FUNCTIONAL CHECK - NEUTRAL]
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 4 current gear: Neutral.
JUDGMENT CRITERIA
^ Shift fork position: 1.8 mm (0.071 inch) or more. (250 millisecond)
OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK - NEUTRAL]
The shift fork position remains 1.8 mm (0.071 inch) or less for 250 millisecond.
LOGIC FLOW CHARTS (Monitor Sequence) [Functional check - Shift fork 4 requested but shift fork 2 movement]
DTC SET CONDITIONS [FUNCTIONAL CHECK - SHIFT FORK 4 REQUESTED BUT SHIFT FORK 2 MOVEMENT]
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.
^ Requested shift fork: Shift fork 4.
JUDGMENT CRITERIA
^ Shift fork position: 6 mm (0.24 inch) [5th gear side] or less, or -6 mm (-0.24 inch) [3rd gear side] or more, or 1.8 mm (0.071 inch) [neutral position] or more, and Initialized fork position shift fork 4 position: 2.5 mm (0.098 inch) or less. (200 millisecond)
OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK - SHIFT FORK 4 REQUESTED BUT SHIFT FORK 2 MOVEMENT]
The status with the shift fork position 6 mm (0.24 inch) [5th gear side] or more, or with -6 mm (-0.24 inch) [3rd gear side] or less, or with 1.8 mm (0.071 inch) [neutral position] or less and with the initialized fork position - shift fork 4 position 2.5 mm (0.098 inch) or more continues for 200 millisecond.
LOGIC FLOW CHARTS (Monitor Sequence) [Functional check - shift fork 4 requested but shift fork 3 movement]
DTC SET CONDITIONS [FUNCTIONAL CHECK - SHIFT FORK 4 REQUESTED BUT SHIFT FORK 3 MOVEMENT]
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.
^ Requested shift fork: Shift fork 4.
JUDGMENT CRITERIA
^ Shift fork position: -6 mm (-0.24 inch) [6th gear side] or more, or 1.8 mm (0.071 inch) [neutral position] or more, and initialized fork position shift fork 4 position: 2.5mm (0.098 inch) or less. (200 millisecond)
OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK - SHIFT FORK 3 REQUESTED BUT SHIFT FORK 4 MOVEMENT]
The status of the shift fork position -6 mm (-0.24 inch) [6th gear side] or less, or with 1.8 mm (0.071 inch) [neutral position] or less and with the initialized fork position - shift fork 3 position 2.5 mm (0.098 inch) or more continues for 200 millisecond.
PROBABLE CAUSES
^ Malfunction of TC-SST-ECU
^ Malfunction of TC-SST shift fork
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. Monitoring unit No. check
1) Check the freeze frame data (item No. 30 to No. 37).
2) Check which monitoring unit (No. 163, No. 180, No. 188, or No. 189) is set.
Q: Which monitoring unit is set, No. 163, No. 180, No. 188, or No. 189?
No. 163: Go to Step 4
Other than No. 163: Go to Step 3
STEP 3. Check whether the DTC is reset.
1) Erase the DTC.
2) Drive with shifting to each gear range.
3) Check that the DTC is reset.
Q: Is DTC No. P184B set?
YES: Replace the mechatronic assembly.
NO: Intermittent malfunction.
STEP 4. Check whether the DTC is reset.
1) Erase the DTC.
2) Drive in the 4th gear.
3) Check that the DTC is reset.
Q: Is DTC No. P184B set?
YES: Go to Step 5.
NO: Intermittent malfunction.
STEP 5. Scan tool Teach-in
1) Carry out the Item No.3: Line pressure Test. Teach-In Reference Table
2) After Teach-In, check which result ("Yes" or "No") is displayed in the Data list No. 101: Normal End. Teach-In Reference Table
Q: Which is displayed, "Yes" or "No"?
"Yes": Go to Step 6
"No" DTC No. P181B: Carry out the troubleshooting for the DTC No. P181B: Clutch 1 (Pressure low range out). P181B
STEP 6. Scan tool Teach-in
1) Carry out the Item No. 1: Plausibility check. Teach-In Reference Table
2) After Teach-In, check which result ("Yes" or "No") is displayed in the Data list No. 101: Normal End. Teach-In Reference Table
Q: Which is displayed, "Yes" or "No"?
"Yes": Replace the transaxle assembly.
"No": Go to Step 7.
STEP 7. Replace the mechatronic assembly, and check if the DTC is reset.
1) Replace the mechatronic assembly.
2) Drive in the 4th gear.
3) Check the DTC.
Q: Is DTC No. P184B set?
YES: Replace the transaxle assembly.
NO: This diagnosis is complete.