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: 650 r/min or more.
^ Time since above engine condition: 1.5 seconds 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
^ Malfunction of power supply circuit (open circuit)

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 the TC-SST-ECU power supply circuit
Inspection Procedure 4: TC-SST-ECU Power Supply Circuit Malfunction.
Q: Is the check result normal?
YES: Go to Step 3.
NO: Repair the TC-SST-ECU power supply circuit. After repairing the power supply circuit, go to Step 3.

STEP 3. Check whether the DTC is reset.
After 10 or more seconds have passed with the engine idle status, check that the DTC is reset.
Q: Is DTC No. P186D set?
YES: Replace the mechatronic assembly.
NO: Intermittent malfunction.