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DTC P186C: High side 3 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 3 circuit is normal.

DESCRIPTIONS OF MONITOR METHODS

The high side 3 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)

P0753: Shift select solenoid 1 system (Open circuit)
P0973: Shift select solenoid 1 system (Short to ground)
P0974: Shift select solenoid 1 system (Short to power supply)
P2727: Clutch/shift pressure solenoid 2 system (Open circuit)
P2728: Clutch/shift pressure solenoid 2 system (Overcurrent)
P2729: Clutch/shift pressure solenoid 2 system (Short to ground)
P2730: Clutch/shift pressure solenoid 2 system (Short to power supply)
P2809: Clutch/shift switching solenoid 2, spool stuck
P2812: Clutch/shift switching solenoid 2 system (Open circuit)
P2814: Clutch/shift switching solenoid 2 system (Short to ground)
P2815: Clutch/shift switching solenoid 2 system (Short to power supply)
P181B: Clutch 1 (Pressure low range out)
P181C: Clutch 1 (Pressure high range out)
P181E: Clutch 2 (Pressure low range out)
P181F: Clutch 2 (Pressure high range out)

Sensor (The sensor below is determined to be normal)

Shift select solenoid 1
Clutch/shift pressure solenoid 2
Clutch/shift switching solenoid 2

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 3 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?

	Go to Step 2.

	Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting .) 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. P186C set?

	Replace the transaxle assembly. (Refer to .)

	Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)