DTC C1840-14 (AWD) (2019 2020 2021)

DTC C1840-14  : Differential Fluid Pressure Sensor Circuit Low Voltage

NOTE:  Before you troubleshoot, review the General Troubleshooting Information .

DTC (AWD)

1. Problem verification

   -1. Start the engine.

   -2. Check the parameter(s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   Voltage of the oil pressure sensor for rear differential	Less than 0.14	V

   Do the current condition(s) match the threshold?

   YES 

   The failure is duplicated. Go to step 2.

   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.

2. Determine possible failure area (PS line, others)

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

   -2. Disconnect the following connector.

   Rear differential fluid pressure sensor 3P connector

   -3. Turn the vehicle to the ON mode.

   -4. Check the parameter(s) below with the HDS.

   Signal	Threshold		Current conditions
   	Values	Unit	Values	Unit
   Voltage of the oil pressure sensor for rear differential	About 5	V

   Do the current condition(s) match the threshold?

   YES 

   Go to step 4.

   NO 

   Go to step 3.

3. Shorted wire check (PS 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.

   Test condition	Vehicle OFF (LOCK) mode
   	Rear differential fluid pressure sensor 3P connector: disconnected
   	AWD control unit 24P connector: disconnected
   Test point 1	Rear differential fluid pressure sensor 3P connector (female terminals) No. 2:
   Test point 2	Body ground

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   Repair a short to the PS wire between the rear differential fluid pressure sensor and the AWD control unit.

   NO 

   The PS wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit , then recheck. If this DTC goes away and the AWD control unit was substituted, replace the original AWD control unit .

4. Determine possible failure area (rear differential fluid pressure sensor, SVCC line)

   -1. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON mode
   	Rear differential fluid pressure sensor 3P connector: disconnected
   Test point 1	Rear differential fluid pressure sensor 3P connector (female terminals) No. 1:
   Test point 2	Rear differential fluid pressure sensor 3P connector (female terminals) No. 3:

   Courtesy of HONDA, U.S.A., INC.

   Is there about 5 V?

   YES 

   Replace the rear differential fluid pressure sensor .

   NO 

   Go to step 5.

5. Open wire check (SVCC 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.

   Test condition	Vehicle OFF (LOCK) mode
   	Rear differential fluid pressure sensor 3P connector: disconnected
   	AWD control unit 24P connector: disconnected
   Test point 1	Rear differential fluid pressure sensor 3P connector (female terminals) No. 3:
   Test point 2	AWD control unit 24P connector No. 20

   Courtesy of HONDA, U.S.A., INC.

   Is there continuity?

   YES 

   The SVCC wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting or substitute a known-good AWD control unit , then recheck. If this DTC goes away and the AWD control unit was substituted, replace the original AWD control unit .

   NO 

   Repair an open in the SVCC wire between the rear differential fluid pressure sensor and the AWD control unit.