Manual Control (F0)

NOTE: This function can be used to manually control the Antilock Brake System (ABS) motors and solenoids.

MOTOR TEST (APPLY/RELEASE)
Each motor can be manually turned on for up to 5 seconds, at a current of 10 amps applied (forward) or 6 amps released (reverse). After running the motors, the command and feedback currents will be stored in a snapshot buffer. This information can be reviewed, when instructed to do so by the trouble tree, to determine if the motors are operating properly. The test below describes how the front motors will normally operate; the rear motor can be tested in a similar manner, except there will be only a slight pedal drop (bump) and rise during the test.
1. Turn ignition switch to "LOCK".
2. Install TECH-1 with ABS/Air Bag Cartridge.
3. Turn ignition switch to "ON".
4. Pump brake pedal until firm to deplete vacuum from power booster.
5. Depress and hold brake pedal.
6. Using the TECH-1, "Release" one of the motors. The brake pedal should move smoothly toward the floor. As the pedal drops, the feedback current should momentarily drop to only a few amps (indicating motor movement) and then become equal to command current (6 amps). This indicates the motor is no longer moving since the piston has reached the bottom of the bore.
7. With the brake pedal still depressed and at the floor, "Apply" the same motor. The brake pedal should now smoothly rise back to the top of its travel. The feedback current should momentarily drop to a few amps, then quickly release to the command current (10 amps). This indicates the motor is no longer moving since the piston has reached the top of the bore ("home" position).

SOLENOID TEST (ON/OFF)

NOTE: Only use this test when no Diagnostic Trouble Code (DTC)s are stored and you suspect a leaky solenoid or check valve.

1. Turn ignition switch to "LOCK".
2. Install TECH-1 with ABS/Air Bag Cartridge.
3. Turn ignition switch to "ON".
4. Pump brake pedal and deplete vacuum from power booster.
5. Select manual control (FO).
6. Select left front or right front motor release.
7. Release the motor for the channel being tested. Review the motor command and feedback currents to be sure the motor released properly.
8. Select the solenoid for the same channel as that being tested.
9. With no brake pedal pressure applied, turn the solenoid on.
10. Depress the brake pedal. It should be very high and firm.

NOTE: If the pedal goes nearly to the floor, the solenoid is leaking or not closing and/or the check valve is leaking, proceed to Step 12.

11. With brake pressure still applied, turn the solenoid off. The brake pedal should move toward the floor. This verifies normal solenoid operation. END OF TEST.

NOTE: If the pedal does not, the solenoid is stuck on, proceed to Step 12.

12. Verify that the solenoid connectors are connected to the proper solenoids, (the right front solenoid is the one on the rear of the modulator, closest to the brake booster). If the wiring is incorrect, move the connectors to the proper solenoid and repeat this entire test starting with Step 1.
A. Physically switch the two solenoids.
B. Repeat the entire test starting at Step 1 for the channel in question.
^ If the test now works properly, test the other channel. If the test fails for this channel, replace the solenoid currently installed in this channel.
^ If the test fails for the same channel, the check valve is leaking. Replace hydraulic modulator.

CAUTION: After performing Step 12 it is necessary to bleed the brake system.