Abs Circuit Check
Disconnect ABS control unit 25-pin connector to perform circuit checks. Control unit is located under brake master cylinder. This test checks integrity of ABS circuits and components. Test also is used to check for intermittent problems. With DVOM connected to selected circuit, perform wiring harness wiggle test to check for poor wiring harness or connector connections. Perform wiggle test while observing DVOM and wiggling related wiring harness or connector. See ABS CIRCUIT QUICK CHECK CHART and 25-PIN CONNECTOR TERMINAL IDENTIFICATION table. See Fig 1 .
ABS CIRCUIT QUICK CHECK CHART
| Circuit Test | Ignition Mode | Measure Between Terminal No. | Scale/Range | Specification |
|---|---|---|---|---|
| ABS Control Unit Ground Check | Off | 8 & Ground | Ohms | 0.0-0.1 Ohm |
| Off | 8 & 24 | Ohms | 0.0-0.45 Ohm | |
| Power Supply (ABS Control Unit Side) | On | 4 & 8 | Volts | 10.0-14.5 Volts |
| ABS Warning Light (ON) | On | 8 & 16 | Volts | 10.0-14.5 Volts |
| Right Front Wheel Speed Sensor | Off | 19 & 20 | k/ohms | 1.0-1.3 k/ohms |
| Left Front Wheel Speed Sensor | Off | 1 & 2 | k/ohms | 1.0-1.3 k/ohms |
| Left Rear Wheel Speed Sensor | Off | 5 & 6 | k/ohms | 1.0-1.3 k/ohms |
| Right Rear Wheel Speed Sensor | Off | 22 & 23 | k/ohms | 1.0-1.3 k/ohms |
| Brakelight Switch (Pedal Released) | Off | 8 & 18 | Volts | 10.0-14.5 Volts |
| Back-Up Power Supply | On Or Off | 9, 25 & 8 | Volts | 10.0-14.5 Volts |
25-PIN CONNECTOR TERMINAL IDENTIFICATION
| Terminal No. | Wire Color |
|---|---|
| 1 | Blue/Green |
| 2 | Blue/Red |
| 4 | Brown |
| 5 | Blue/Yellow |
| 6 | Blue/Red |
| 7 | White/Yellow |
| 8 | Black |
| 9 | White |
| 16 | Brown/Blue |
| 18 | Red/Black |
| 19 | Light Green/Red |
| 20 | Light Green/Yellow |
| 22 | Light Green/Red |
| 23 | Light Green/Black |
| 24 | Black |
| 25 | Pink |