Test 4A: Inlet Valve Circuits
NOTE:
Perform TEST 1A: CHECKING SYSTEM FOR DIAGNOSTIC TROUBLE CODES (DTCS)
before proceeding. For connector terminal ID, see CONNECTOR IDENTIFICATION
. For wiring diagram, see WIRING DIAGRAMS
.
- DTC may be caused by loose connections or defective valves in HCU, loose connection between CAB and HCU, defective CAB or defective HCU. Go to next step.
- Using scan tool, read DTCs. If scan tool displays VALVE POWER FEED CIRCUIT, perform TEST 20A: VALVE POWER FEED CIRCUIT . If scan tool does not display VALVE POWER FEED CIRCUIT, go to next step.
- Turn ignition off. Remove CAB from HCU. See CONTROLLER ANTI-LOCK BRAKE (CAB) under REMOVAL & INSTALLATION. Inspect valve block connector on bottom of pump/motor and HCU for damaged or pushed-out terminals. See Fig 1 . If terminals are okay, go to next step. If terminals are damaged or pushed-out, replace HCU. Perform TEST VER-1A: VERIFICATION TEST .
- Using an external ohmmeter, check resistance between HCU terminal No. 7 and suspected HCU inlet valve terminal. See HCU TERMINAL IDENTIFICATION table. If resistance is 5-8 ohms, replace CAB. Perform TEST VER-1A: VERIFICATION TEST . If resistance is not as specified, replace HCU. Perform TEST VER-1A.
HCU TERMINAL IDENTIFICATION
| Terminal No. | Function |
|---|---|
| 1 | Traction Control Valve No. 2 |
| 3 | Left Front Inlet Valve |
| 4 | Right Rear Inlet Valve |
| 5 | Left Rear Inlet Valve |
| 6 | Right Front Inlet Valve |
| 7 | B+ Main Relay Output |
| 9 | Traction Control Valve No. 2 |
| 10 | Left Front Outlet Valve |
| 11 | Right Rear Outlet Valve |
| 12 | Left Rear Outlet Valve |
| 13 | Right Front Outlet Valve |
| 14 | B+ Main Relay Output |