P1888

This article has been updated by Technical Service Bulletin 09-22-005 dated March of 2009.














DTC P1888: SHIFT FORK 4 JUMP OUT

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 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 - 4th gear

DTC SET CONDITIONS [FUNCTIONAL CHECK - 4TH GEAR]

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 4 current gear: 4th gear.

Judgment Criteria
- Shift fork position: 6 mm (0.24 inch) or less, and input shaft 2 (even) speed: 500 r/min or more, or synchro (4th gear) slip speed: 80 r/min or more. (400 millisecond)

OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK - 4TH GEAR]
The status with the shift fork position 6 mm (0.24 inch) or more and with the input shaft 2 (even) speed 500 r/min or less, or with the synchro (4th gear) slip speed 80 r/min or less continues for 400 milliseconds.

LOGIC FLOW CHARTS (Monitor Sequence)






Functional check - 2nd gear

DTC SET CONDITIONS [FUNCTIONAL CHECK - 2ND GEAR]

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 4 current gear: 2nd gear.

Judgment Criteria
- Shift fork position: -6 mm (-0.24 inch) or more, and input shaft 2 (even) speed: 500 r/min or more, or synchro (2nd gear) slip speed: 80 r/min or more. (400 millisecond)

OBD-II DRIVE CYCLE PATTERN [FUNCTIONAL CHECK - 2ND GEAR]
The status with the shift fork position -6 mm (-0.24 inch) or less and with the input shaft 2 (even) speed 500 r/min or less, or with the synchro (2nd gear) slip speed 80 r/min or less continues for 400 milliseconds.

PROBABLE CAUSES
- Malfunction of TC-SST-ECU
- Malfunction of TC-SST shift fork
- 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. Scan Tool Testing and Procedures
After repairing the CAN bus line, go to Step 2.

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

Q. Is DTC No.P1888 set?
YES: Go to Step 3.
NO: Intermittent malfunction. (Refer to - How to Cope with Intermittent Malfunction. How to Use Troubleshooting/Inspection Service Points

STEP 3. Replace the mechatronic assembly, and check if the DTC is reset.
1) Replace the mechatronic assembly.
2) Drive with shifted in the 2nd gear and 4th gear.
3) Check the DTC.

Q. Is DTC No.P1888 set?
YES: Replace the transaxle assembly.
NO: This diagnosis is complete.