P186D

DTC P186D: High side 1 system (Voltage low range 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 high side 1 circuit is normal.

DESCRIPTIONS OF MONITOR METHODS
The voltage of the high side 1 circuit is determined to be too low.

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.
^ Engine speed: 500 r/min or more.
^ Time since above engine condition: 400 millisecond or more.
^ FET (Field Effect Transistor) of high side 1: Switched off.

JUDGMENT CRITERIA
^ FET output: 100 mV or less. (5 seconds)

OBD-II DRIVE CYCLE PATTERN
The FET channel output remains 100 mV or more for 5 seconds.

PROBABLE CAUSES
^ Malfunction of TC-SST-ECU

DIAGNOSTIC PROCEDURE

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.

Q: Is DTC No. P186D set?
YES: Replace the TC-SST assembly.
NO: Intermittent malfunction.