DESCRIPTION & OPERATION
The Variable Assist Power Steering (VAPS) system controls the level of power assistance available to the driver based on vehicle speed. (Scheme 1) At speeds less than 2 MPH, full power steering assist is provided to lessen steering efforts and increase maneuverability. As vehicle speed increases from 2 MPH up to 119 MPH, steering assist will gradually decrease at a calibrated rate to increase steering efforts for improved directional stability and road feel. At speeds greater than 119 MPH, steering assist is constant.
The Front Electronic Module (FEM) provides a Pulse-Width Modulated (PWM) current to the control valve actuator. (Scheme 2) The control valve actuator regulates the hydraulic valve, determining the amount of hydraulic assist provided to the steering gear.
| CAUTION | When repair procedure requires vehicle to be raised on a hoist, air suspension should be turned off. Suspension switch is located in left side of trunk. DO NOT turn air suspension switch on until repair is complete, vehicle is lowered and vehicle weight exists on all wheels. |
Scheme 1
Scheme 2
CONNECTOR IDENTIFICATION
Note. Use illustration to identify terminals referenced in testing. (Scheme 3) Also, see appropriate table.
Scheme 3
| Terminal No. | Wire Color | Circuit Description |
|---|---|---|
| 1 | ORG/WHT | Constant Switched Battery Voltage |
| 2 | BRN/GRN | Sensor Ground |
| 3 | — | — |
| 4 | BLK/YEL | Switched Ground |
| 5 | BLK/WHT | Switched Ground |
| 6 | BLK/GRN | Ground |
| 7 | BLK/WHT | Switched Ground |
| 8 | BLK/RED | Switched Ground |
| 9 | WHT/GRN | Sensor Signal |
| 10 | BLK/RED | Switched Ground |
| 11 | BLK/RED | Ground |
| 12 | — | — |
| 13 | BLK/RED | Ground |
| 14 | BLK/RED | Ground |
| 15 | BLK/RED | Ground |
| 16 | — | — |
| 17 | BLK/GRN | Switched Ground |
FEM CONNECTOR C201a TERMINAL IDENTIFICATION
| Terminal No. | Wire Color | Circuit Description |
|---|---|---|
| 1 | BLU | Data Link Bus (Negative) |
| 2 | BLK/BLU | Switched Ground |
| 3 | WHT | Sensor Signal |
| 4 | — | — |
| 5 | BLK/GRN | Switched Ground |
| 6 | ORG/GRN | Constant Voltage |
| 7 | GRAY | Data Link Bus (Positive) |
| 8 | BRN/RED | Switched Ground |
| 9 | WHT/GRN | Sensor Signal |
| 10 | BLK/RED | Switched Ground |
| 11 | WHT/RED | Sensor Signal |
| 12 | BLK/RED | Ground |
FEM CONNECTOR C201c TERMINAL IDENTIFICATION
| Terminal No. | Wire Color | Circuit Description |
|---|---|---|
| 1 | ORG/YEL | Switched Constant Battery Voltage |
| 2 | WHT/RED | Sensor Signal |
| 3 | PNK/ORG | Voltage (Hot In RUN Only) |
| 4 | — | — |
| 5 | BRN | Switched Ground |
| 6 | — | — |
| 7 | — | — |
| 8 | BLK/YEL | Switched Ground |
| 9 | — | — |
| 10 | — | — |
| 11 | BLU/RED | Variable Switched DC Voltage |
| 12 | ORG | Constant Switched Battery Voltage |
| 13 | GRY/VIO | Signal 2 (Reverse, Downward) |
| 14 | YEL | Constant Sensor DC Voltage |
| 15 | YEL/VIO | Constant Switched Sensor DC Voltage |
| 16 | — | — |
| 17 | — | — |
| 18 | BRN/RED | Sensor Ground |
| 19 | BLK/GRN | Switched Ground |
| 20 | — | — |
FEM CONNECTOR C201f TERMINAL IDENTIFICATION