Deviation Pressure Low

Control System DTCs

DTC Troubleshooting: C1858-72

DTC C1858-72 : Differential Fluid Pressure Deviation Low

NOTE: Before you troubleshoot, review the how to troubleshoot the real time AWD system.

1. Rear differential fluid level check:

-1. Check the rear differential fluid level Rear Differential Fluid Inspection (AWD/4WD), and check for rear differential fluid leakage.

Is the check result OK?
-YES- Go to step 2.
-NO- Find and repair the source of the fluid leak then add recommended fluid Rear Differential Fluid Replacement (KA, KC Models AWD).

2. Problem verification (function test with HDS):

-1. Turn the ignition switch to ON (II).

-2. Do the Oil Pressure Control Test in the Functional Test Menu with the HDS Rear Differential Pressure Test.

Is the test result OK?
-Fault code is not indicated- Intermittent failure, the system is OK at this time.
-Fault code 2-1 or 5-1 is indicated- Go to step 3.
-Fault code 3-1 is indicated- Go to step 4.
-Fault code except 2-1, 3-1, and 5-1 is indicated- Go to step 5.

3. Hydraulic system check 1:

-1. Do the Air Bleeding in the Adjustment Menu with the HDS Procedures.

-2. Do the Oil Pressure Control Test in the Functional Test Menu with the HDS Rear Differential Pressure Test.

Is the test result OK?
-YES- System is OK at this time.
-NO- Replace the rear differential fluid Rear Differential Fluid Replacement (KA, KC Models AWD) then do the rear differential fluid pressure sensor test Rear Differential Fluid Pressure Sensor Test and do the rear differential solenoid valve test Testing and Inspection. If they are OK, replace the rear differential assembly.

4. Hydraulic system check 2:

-1. Do the Air Bleeding in the Adjustment Menu with the HDS Procedures.

-2. Do the Oil Pressure Control Test in the Functional Test Menu with the HDS Rear Differential Pressure Test.

Is the test result OK?
-YES- System is OK at this time.
-NO- Replace the rear differential fluid Rear Differential Fluid Replacement (KA, KC Models AWD), then do the rear differential solenoid valve test Testing and Inspection. If it is OK, replace the rear differential assembly.

5. DTC check:

-1. Do the Oil Pressure Control Test in the Functional Test Menu with the HDS Rear Differential Pressure Test three times.

-2. Check for DTCs with the HDS.

Are there any DTCs?
-YES- Go to the indicated DTC's troubleshooting.
-NO- System is OK at this time.