DTC C1840-12 (47-01) (AWD)

DTC C1840-12  : Differential Fluid Pressure Sensor Circuit High Voltage

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

DTC (Real Time AWD)

1. Determine possible failure area (electrical circuit problem, hydraulic circuit problem)

   -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	More than 4.14	V

   Do the current condition (s) match the threshold?

   YES 

   Go to step 3.

   NO 

   Go to step 2.

2. Problem verification

   -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 FUNCTIONAL TEST in the REAL TIME AWD with the HDS.

   -5. Do the OIL PRESSURE CONTROL TEST in the FUNCTIONAL TEST with the HDS .

   Oil Pressure Control Test

   Is the test result OK?

   YES 

   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.

   NO 

   The failure is duplicated. Follow the instructions indicated on the HDS according to the test result .

3. Determine possible failure area (short to power in PS1 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. 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. 2:

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

   Is there about 4.14 V or more?

   YES 

   Go to step 4.

   NO 

   Go to step 7.

4. Shorted wire check (PS1 line to power)

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

   -2. Disconnect the following connector.

   AWD control unit 24P connector

   -3. Turn the vehicle to the ON mode.

   -4. Measure the voltage between test points 1 and 2.

   Test condition	Vehicle ON 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 about 0.5 V or more?

   YES 

   Repair a short to power in the PS1 wire between the rear differential fluid pressure sensor and the AWD control unit.

   NO 

   Go to the 5.

5. Shorted wire check (PS1 line to SVCC line)

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

   -2. 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	Rear differential fluid pressure sensor 3P connector (female terminals) No. 3:

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

   Is there continuity?

   YES 

   Repair a short in the PS1 wire to the SVCC wire between the rear differential fluid pressure sensor and the AWD control unit.

   NO 

   Go to step 6.

6. Rear differential fluid pressure sensor check

   -1. Connect the following connector.

   AWD control unit 24P connector

   -2. Connect terminals A and B with a jumper wire.

   Terminal A	Rear differential fluid pressure sensor 3P connector (female terminals) No. 1:
   Terminal B	Rear differential fluid pressure sensor 3P connector (female terminals) No. 2:

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

   -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	Less than 0.1	V

   Do the current condition (s) match the threshold?

   YES 

   Replace the rear differential fluid pressure sensor .

   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 .

7. Determine possible failure area (open in PS1 line, others)

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

   -2. Connect terminals A and B with a jumper wire.

   Terminal A	Rear differential fluid pressure sensor 3P connector (female terminals) No. 2:
   Terminal B	Body ground

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

   -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	Less than 0.1	V

   Do the current condition (s) match the threshold?

   YES 

   Go to step 9.

   NO 

   Go to step 8.

8. Open wire check (PS1 line)

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

   -2. Remove the jumper wire.

   -3. Disconnect the following connector.

   AWD control unit 24P connector

   -4. 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	AWD control unit 24P connector No. 21

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

   Is there continuity?

   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 an open in the PS1 wire between the rear differential fluid pressure sensor and the AWD control unit.

9. Open wire check (SG line)

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

   -2. Remove the jumper wire.

   -3. Disconnect the following connector.

   AWD control unit 24P connector

   -4. 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. 1:
   Test point 2	Real time AWD control unit 24P connector No. 11

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

   Is there continuity?

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