AWD Light Comes On and Sets DTC C1858-73 – 2013-2014 Acura RDX

May 6, 2015
01425-01942 Version 2


AWD Light Comes On and Sets DTC C1858-73



Year Model Trim VIN range
2013–14 RDX ALL with AWD ALL with AWD



Under PARTS INFORMATION, the AWD Fluid part number was changed.



The electric differential pressure solenoid (EDPS) has excessive oil pressure, causing the AWD indicator to come on and DTC C-1858-73 (differential fluid pressure deviation high) to set.



There is abnormal wear on the EPDS solenoid plunger.



Replace the EDPS solenoid in the rear differential.



Part Name Part Number Quantity
Solenoid Assembly 48350-R7L-013 1
Bolt (12 point 8 mm x 21 mm) 90113-S10-000 4
Flange Bolt (10 mm x 31 mm) 90164-S3V-A00 4
Flange Bolt (8 mm x 14 mm) 95701-08014-08  2
Drain Washer (20 mm) 94109-20000  1
Drain Washer (18 mm) 90471-PX4-000  1
O-ring (7.7 mm x 2.3 mm) 91301-PC9-003  1
O-ring (28.4 mm x 2.4 mm) 91306-R7L-003 1
Clip 91540-STK-003  1
Liquid Gasket 08718-0004  1
AWD Fluid 08200-9007A  2



The normal warranty applies.

Operation Number Description Flat Rate Time Failed Part Number
2191Y0 Replace the EPDS solenoid. 1.4 hours 48350-R7L-003

Defect Code: 03217
Symptom Code: 03214
Skill Level: Repair Technician



  1. Raise the vehicle on a lift and make sure it is securely supported.
  2. Shift into Neutral.
  3. Remove the oil filler plug and sealing washer from the rear differential.

oil filler plug


  1. Remove the drain plug and sealing washer, then drain the rear differential fluid.

drain plug


  1. Remove the No. 1 propeller shaft protector.

No. 1 propeller shaft protector


  1. Disconnect the propeller shaft from the rear differential:

Disconnect the propeller shaft from the rear differential


  1. Support the rear differential with a jack. Remove the mounting bolts and lower the differential about 1 inch.

Support the rear differential with a jack


  1. Disconnect the breather hose from the pump motor breather pipe, then remove the harness bracket.

breather hose


  1. Disconnect the connector.



  1. Remove the rear differential pump motor and the O-ring.

rear differential pump motor


  1. Remove the connector cover.

connector cover


  1. Disconnect the EPDS connector, then remove the solenoid connector.

EPDS connector


  1. Remove the bolts, then remove the torque control differential assembly.

torque control differential assembly


  1. Remove the three shims from the pump housing assembly and note the order from which they were removed.

NOTE: Make sure the large 101.5 mm shim fits into the tabs on reassembly. If the shims are removed or fall out while doing the repair, note the orientation of the shims and reinstall in the order shown.

three shims


  1. Remove the four bolts from the pump housing assembly to remove it.

pump housing assembly


  1. Remove the EPDS solenoid.

NOTE: If Service Bulletin 14-047, Noise From the Rear Differential, was done, make sure the intermediate drive joint does not fall out when handling the pump housing.

EPDS solenoid


  1. Install the new EPDS solenoid and torque the bolts to 12 N·m (9 lb-ft).
  2. Replace the O-ring with a new one.



  1. Install the pump housing assembly and torque the bolts to 12 N·m (9 lb-ft).
  2. Install the shims in the order of removal and make sure the tabs are in place.
  3. Remove the old gasket and any dirt and oil from the mating surface.
  4. Apply liquid gasket evenly to the entire sealing surface and install the component within 5 minutes of applying it.

NOTE: Allow the liquid gasket to cure for 30 minutes after assembly before filling the differential with the recommended fluid.

  1. Install the torque control differential assembly and torque the bolts to 12 N·m (9 lb-ft).
  2. Install the solenoid connector and the EPDS connector.
  3. Install the connector cover.
  4. Install the rear differential pump motor with a new O-ring and torque the bolts to 12 N·m (9 lb-ft).
  5. Connect the connector.
  6. Install the harness bracket and the breather hose to the pipe.
  7. Install the new mounting bolts and torque them to 44 N·m (32 lb-ft).
  8. Install the propeller shaft:
    • Attach the propeller shaft to the rear differential companion flange by aligning the reference mark you made in step 6.
    • Install the new bolts and torque them to 32 N·m (24 lb-ft).
  9. Install the propeller shaft protector and torque the bolts to 22 N·m (16 lb-ft).
  10. Clean the drain plug, and install it with a new sealing washer, then torque it to 47 N·m (35 lb-ft).
  11. Refill the differential to the proper level.
  12. Install the oil filler plug with a new sealing washer and torque the plug to 47 N·m 35 lb-ft).
  13. Connect the HDS to the DLC.
  14. Turn the ignition to ON.
  15. Make sure the HDS communicates with the vehicle. If it does not communicate, go to the DLC circuit troubleshooting.

NOTE: See the HDS Help menu for specific instructions.




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