DTC Troubleshooting: C1851-19 (63-02), C1851-1E (63-03), C1851-1E (63-04) (AWD)

1.

Problem verification (with engine idling):

Problem verification (with engine idling)

?1.	Turn the vehicle to the ON mode.

?2.	Clear the DTC with the HDS.

?3.	Turn the vehicle to the OFF (LOCK) mode.

?4.	Start the engine.

?5.

Check for DTCs with the HDS.

DTC Description	DTC	Freeze Frame
C1851-19 Control Module Internal Control Module Malfunction
C1851-1E Motor Circuit High Current

Is DTC C1851-19 or C1851-1E indicated?


	YES

The failure is duplicated. Go to step 3.


	NO

Go to step 2.

2.

Problem verification (with rear differential pump motor running):

Problem verification (with rear differential pump motor running)

?1.	Clear the DTC with the HDS.

?2.	Turn the vehicle to the OFF (LOCK) mode.

?3.	Turn the vehicle to the ON mode.

?4.	Select the ADJUSTMENT in the REAL TIME AWD with the HDS.

?5.	With the engine running, do the AIR BLEEDING in the ADJUSTMENT with the HDS.

?6.

Check for DTCs with the HDS.

DTC Description	DTC	Freeze Frame
C1851-19 Control Module Internal Control Module Malfunction
C1851-1E Motor Circuit High Current

Is DTC C1851-19 or C1851-1E indicated?


	YES

The failure is duplicated. Go to step 3.


	NO

Intermittent failure, the system is OK at this time. If the freeze data/on-board snapshot of this DTC is recorded, try to reproduce the failure under the same conditions with the freeze data/on-board snapshot.?

3.

Determine possible failure area (short to power in MH, ML lines, others):

Determine possible failure area (short to power in MH, ML lines, others)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.

Disconnect the following connector.

Rear differential pump motor 2P connector

?3.	Turn the vehicle to the ON mode.

?4.	Wait for 10 seconds.

?5.

Measure the voltage between the following test points 1 and 2 individually (see table).

Test condition	Vehicle ON mode
	Rear differential pump motor 2P connector: disconnected

Connector	Test point 1	Test point 2
Rear differential pump motor 2P connector (female terminals)	No. 1:	Body ground
	No. 2:	Body ground

Is there about 0.1 V or less?


	YES

Go to step 5.


	NO

Go to step 4.

4.

Shorted wire check (MH line to power, ML line to power):

Shorted wire check (MH line to power, ML line to power)

?1.

Disconnect the following connector.

AWD control unit 24P connector

?2.	Turn the vehicle to the ON mode.

?3.

Measure the voltage between the following test points 1 and 2 individually (see table).

Test condition	Vehicle ON mode
	Rear differential pump motor 2P connector: disconnected
	Real time AWD control unit 24P connector: disconnected

Connector	Test point 1	Test point 2
Rear differential pump motor 2P connector (female terminals)	No. 1:	Body ground
	No. 2:	Body ground

Is there about 0.1 V or less?


	YES

Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit, and recheck. If the symptom/indication goes away with a known-good AWD control unit, replace the original AWD control unit.?


	NO

Repair short to power in the MH and/or ML wires between the rear differential pump motor and the AWD control unit.?

5.

Determine possible failure area (short to ground in MH line, others):

Determine possible failure area (short to ground in MH line, others)

?1.	Turn the vehicle to the OFF (LOCK) mode.

?2.

Connect the following connector.

Rear differential pump motor 2P connector

?3.

Disconnect the following connector.

AWD control unit 24P connector

?4.

Check for continuity between the following test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
Test condition	AWD control unit 24P connector: disconnected
Test point 1	AWD control unit 24P connector No. 1
Test point 2	Body ground

Is there continuity?


	YES

Go to step 6.


	NO

Go to step 7.

6.

Rear differential pump motor internal shorted check:

Rear differential pump motor internal shorted check

?1.

Disconnect the following connector.

Rear differential pump motor 2P connector

?2.

On the rear differential pump motor side, check for continuity between the test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Rear differential pump motor 2P connector: disconnected
	AWD control unit 24P connector: disconnected
Test point 1	Rear differential pump motor 2P connector (male terminals) No. 2:
Test point 2	Body ground

Is there continuity?


	YES

Replace the rear differential pump motor.?


	NO

Repair short to ground in the MH wire between the rear differential pump motor and the AWD control unit.?

7.

Determine possible failure area (short in MH, ML line, others):

Determine possible failure area (short in MH, ML line, others)

?1.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	AWD control unit 24P connector: disconnected
Test point 1	AWD control unit 24P connector No. 1
Test point 2	AWD control unit 24P connector No. 3

Is there continuity?


	YES

Go to step 8.


	NO

Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit, and recheck. If the symptom/indication goes away with a known-good AWD control unit, replace the original AWD control unit.?

8.

Shorted wire check (MH line to ML line):

Shorted wire check (MH line to ML line)

?1.

Disconnect the following connector.

Rear differential pump motor 2P connector

?2.

Check for continuity between test points 1 and 2.

Test condition	Vehicle OFF (LOCK) mode
	Rear differential pump motor 2P connector: disconnected
	AWD control unit 24P connector: disconnected
Test point 1	Rear differential pump motor 2P connector (female terminals) No. 1:
Test point 2	Rear differential pump motor 2P connector (female terminals) No. 2:

Is there continuity?


	YES

Repair a short in the MH wire to the ML wire between the rear differential pump motor and the AWD control unit.?


	NO

Replace the rear differential pump motor.?