Honda HR-V: DTC C1851-18 (63-01): Motor Circuit Low Current (AWD)

NOTE: Before you troubleshoot, review the General Troubleshooting Information for the AWD with intelligent control system.

1. Problem verification (with engine idling):

1. Turn the vehicle to the ON mode.
2. Clear the DTC with the HDS.
3. Start the engine.
4. Check for DTCs with the HDS.

Is DTC C1851-18 indicated?

YES

The failure is duplicated. Go to step 3.

NO

Go to step 2.

2. Problem verification (with rear differential pump motor running):

1. Clear the DTC with the HDS.
2. Select ADJUSTMENT in the AWD WITH INTELLIGENT CONTROL with the HDS.
3. With the engine running, do the AIR BLEEDING in the ADJUSTMENT with the HDS.
4. Check for DTCs with the HDS.

Is DTC C1851-18 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. Open wire check (GND line):

1. Turn the vehicle to the OFF (LOCK) mode.
2. Disconnect the following connector.

AWD control unit 24P connector

3. Check for continuity between test points 1 and 2.

Is there continuity?

YES

The GND wire is OK. Go to step 4.

NO

Check for poor connections or loose terminals between the AWD control unit and ground (G505). If the connections are OK, repair an open in the GND wire between the AWD control unit and ground (G505).

4. Determine possible failure area (short in MH, ML lines, open in MH, ML lines):

Check for continuity between test points 1 and 2.

Is there continuity?

YES

Go to step 7.

NO

Go to step 5.

5. Determine possible failure area (MH, ML lines, AWD control unit):

Measure the resistance between test points 1 and 2.

Is there about 10 Ω or less?

YES

Update the AWD control unit if it does not have the latest software, or substitute a known-good AWD control unit, and recheck. If the symptom/indication goes away with the updated AWD control unit, troubleshooting is complete. If the symptom/indication goes away with a known-good AWD control unit, replace the original AWD control unit.

NO

Go to step 6.

6. Rear differential pump motor internal open check:

1. Disconnect the following connector.

Rear differential pump motor 2P connector

2. Measure the resistance between test points 1 and 2.

Is there about 10 Ω or less?

YES

Repair an open in the MH and/or ML wires between the rear differential pump motor and the AWD control unit.

NO

Replace the rear differential pump motor.

7. 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 following test points 1 and 2 individually (see table).

Are there continuity?

YES

Replace the rear differential pump motor.

NO

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

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