P1866

DTC P1866: High side 2 system (Overcurrent)

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 high side 2 circuit is normal.

DESCRIPTIONS OF MONITOR METHODS
The supply current to the high side 2 is determined to be overcurrent.

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)
^ P0776: Clutch cooling flow solenoid system (Drive current range out)
^ P0777: Clutch cooling flow solenoid system (Stuck)
^ P0964: Clutch cooling flow solenoid system (Open circuit)
^ P0965: Clutch cooling flow solenoid system (Overvoltage)
^ P0966: Clutch cooling flow solenoid system (Short to ground)
^ P0967: Clutch cooling flow solenoid system (Short to power supply)
^ P2718: Clutch/shift pressure solenoid 1 system (Open circuit)
^ P2719: Clutch/shift pressure solenoid 1 system (Overcurrent)
^ P2720: Clutch/shift pressure solenoid 1 system (Short to ground)
^ P2721: Clutch/shift pressure solenoid 1 system (Short to power supply)
^ P2733: Clutch/shift switching solenoid 1, spool stuck
^ P2736: Clutch/shift switching solenoid 1 system (Open circuit)
^ P2738: Clutch/shift switching solenoid 1 system (Short to ground)
^ P2739: Clutch/shift switching solenoid 1 system (Short to power supply)
^ P181B: Clutch 1 (Pressure low range out)
^ P181C: Clutch 1 (Pressure high range out)

Sensor (The sensor below is determined to be normal)
^ Clutch cooling flow solenoid
^ Clutch/shift pressure solenoid 1
^ Clutch/shift switching solenoid 1

LOGIC FLOW CHARTS (Monitor Sequence)





DTC SET CONDITIONS

Check Conditions
^ Voltage of battery: 8 V or more.
^ Voltage of battery: 16.5 V or less.
^ High side 2 switch: ON.

JUDGMENT CRITERIA
^ FET (Field Effect Transistor) current: 8.1 A or more, and FET (Field Effect Transistor) output: 100 mV or less. (1 second)

OBD-II DRIVE CYCLE PATTERN
The status with the current of the FET channel shunt 8.1 A or less and with the FET channel output 100 mV or more continues for 1 second.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU

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.
After 5 or more seconds have passed with the engine idle status, check that the DTC is reset.
Q: Is DTC No. P1866 set?
YES: Replace the mechatronic assembly.
NO: Intermittent malfunction.