P1877

DTC P1877: Gear Block 2nd

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 2nd gear is determined to be impossible.

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)

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

- Not applicable

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions

- Engine speed: 650 r/min or more.
- Time since above engine condition: 1.5 seconds or more.
- Target gear: 2nd gear.
JUDGMENT CRITERIA

- Gear (synchro) engagement: 3 times blocked. (immediately)

OBD-II DRIVE CYCLE PATTERN

The 2nd gear is engaged.

PROBABLE CAUSES

- Malfunction of TC-SST-ECU
- Malfunction of TC-SST gear
- Malfunction of clutch assembly

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. CAN Bus Diagnostics Chart.) After repairing the CAN bus line, go to Step 2.
STEP 2. Check the fluid.

Q. Is the fluid level proper?

YES Go to Step 3.
NO Add the fluid.
STEP 3. Check whether the DTC is reset.

(1)Erase the DTC.

(2)Drive with shifted in the 2nd gear.

(3)Check that the DTC is reset.

Q. Is DTC No.P1877 set?

YES Replace the transaxle assembly. (Refer to Removal and Replacement.)
NO Intermittent malfunction. How to Cope With Intermittent Malfunctions.)