P1864

DTC P1864: High side 1 system (Short to power supply)

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 1 circuit is normal.

DESCRIPTIONS OF MONITOR METHODS
The high side 1 circuit is determined to be short to power supply.

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)
^ P0758: Shift select solenoid 2 system (Open circuit)
^ P0976: Shift select solenoid 2 system (Short to ground)
^ P0977: Shift select solenoid 2 system (Short to power supply)
^ P0746: Line pressure solenoid system (Drive current range out)
^ P0960: Line pressure solenoid system (Open circuit)
^ P0961: Line pressure solenoid system (Overvoltage)
^ P0962: Line pressure solenoid system (Short to ground)
^ P0963: Line pressure solenoid system (Short to power supply)
^ P0968: Shift/cooling switching solenoid system (Open circuit)
^ P0970: Shift/cooling switching solenoid system (Short to ground)
^ P0971: Shift/cooling switching solenoid system (Short to power supply)

Sensor (The sensor below is determined to be normal)
^ Shift select solenoid 2
^ Line pressure solenoid
^ Shift/cooling switching solenoid

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 1 switch: OFF.

JUDGMENT CRITERIA
^ FET (Field Effect Transistor): Can't be switched off. (12 seconds)

OBD-II DRIVE CYCLE PATTERN
The FET switch remains OFF for 12 seconds.

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 15 seconds with the engine idle status, check that the DTC is reset.
Q: Is DTC No. P1864 set?
YES: Replace the mechatronic assembly.
NO: Intermittent malfunction.