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Left Steer | Left Drive | Left |
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FIGURE 8 - VEHICLE ORIENTATION (TYPICAL)
ECU Configuration Test
Within two seconds of the application of ignition power, the ECU will perform a test to detect system configuration with regards to the number of wheel speed sensors and PMVs. This can be audibly detected by a rapid cycling of the PMVs. (Note: The ECU will not perform the configuration test when wheel speed sensors show that the vehicle is in motion.)
Pressure Modulator Valve Chuff Test
After the performance of the configuration test, the
With brake pressure applied, a properly installed PMV will perform one sharp audible exhaust of air by activating the hold solenoid twice and the release solenoid once. If the PMV is wired incorrectly, it will produce two exhausts of air or none at all.
The
•Steer Axle Right PMV
•Steer Axle Left PMV
•Drive Axle Right PMV
•Drive Axle Left PMV
•Additional Axle Right PMV
•Additional Axle Left PMV
The pattern will then repeat itself.
The ECU will not perform the PMV Chuff Test when wheel speed sensors show that the vehicle is in motion.
6
ABS OPERATION
Bendix ABS uses wheel speed sensors, ABS modulator valves, and an ECU to control either four or six wheels of a vehicle. By monitoring individual wheel turning motion during braking, and adjusting or pulsing the brake pressure at each wheel, the
Steer Axle Control
Although both wheels of the steer axle have their own wheel speed sensor and pressure modulator valve, the
Single Drive Axle Control (4x2 Vehicle)
For vehicles with a single rear drive axle (4x2), the brakes are operated independently by the
Dual Drive Axle Control (4S/4M Configuration)
For vehicles with dual drive axles (6x4) using a 4S/4M configuration, one ABS modulator controls both
Dual Rear Axle Control (6S/6M Configuration)
For vehicles with dual rear axles (6x4, 6x2) using a 6S/6M configuration, the rear wheels are controlled independently. Therefore, brake application pressure at each wheel is adjusted according to the individual wheel behavior on the road surface.
6x2 Vehicles with 6S/5M Configuration
6x2 vehicles can utilize a 6S/5M configuration, with the additional axle (a