Test A: Intermittent Valve Failure

NOTE: This test is associated with DTC C1101.

Measure Valve Resistance At HCU

- Disconnect Hydraulic Control Unit (HCU) 8-pin connector. Measure resistance between designated HCU component pin numbers. See HCU PIN NUMBER IDENTIFICATION table. All inlet valves should have 5-8 ohms resistance. All outlet valves should have 3-6 ohms of resistance. If resistance is as specified, go to next step. If resistance is not as specified, replace HCU and bleed brake system. See BLEEDING BRAKE SYSTEM . Go to step 5).

NOTE: Valve resistance will change rapidly. While monitoring valve resistance, tap ABS HCU lightly with a rubber mallet to simulate rough road driving conditions.

HCU PIN NUMBER IDENTIFICATION

Application

⁽¹⁾ Pins No.

Left Front Inlet

1 & 6; 4 & 6

Left Front Outlet

1 & 7; 4 & 7

Rear Inlet

1 & 2; 2 & 4

Rear Outlet

1 & 3; 3 & 4

Right Front Inlet

1 & 8; 4 & 8

Right Front Outlet

1 & 5; 4 & 5

⁽¹⁾	For pin locations, see WIRING DIAGRAMS .

Check For Valve Block Short

- Measure resistance between ground and pin No. 1 at component side of HCU 8-pin connector and valve block. Measure resistance between ground and pin No. 4 at component side of HCU 8-pin connector and valve block. If resistances are 10 megohms or more, go to next step. If resistances are less than 10 megohms, replace HCU and bleed brake system. See BLEEDING BRAKE SYSTEM . Go to step 5).

Check For Intermittent Battery Voltage

- Install Breakout Box (014-00322) with proper overlay. Connect a jumper wire between breakout box pins No. 19 and 14. Turn ignition switch to ON position. Measure voltage between breakout box pins No. 17 and 1. While monitoring voltage, tap ABS HCU lightly with a rubber mallet to simulate rough road driving conditions. If voltage drops below 9 volts at any time, locate and repair source of high resistance in Orange/Yellow wire between HCU and main relay, or Tan/Yellow wire between battery and main relay. Go to step 5). If voltage does not drop below 9 volts at any time, go to next step.

Perform Intermittent Diagnosis

- rform SYMPTOM H: INTERMITTENT DIAGNOSIS PROCEDURE under SYMPTOM TESTS for affected circuits. If wiring fault is located, replace wiring as necessary and go to next step. If no wiring fault is located, replace ABS control module and go to next step.

Verification

- Turn ignition switch to OFF position. Reconnect and reassemble all components. Clear all codes. Drive vehicle over rough road and through a car wash. Retrieve codes. If SYSTEM PASS is present, condition has been repaired and test is complete. If original code is present, repeat test procedures beginning at step 1). If a different code is present, go to appropriate trouble code test. See TROUBLE CODE DIRECTORY under TROUBLE CODE TESTS.