Test 8A - Excess Decay

Test 8A: Repairing -- Excess Decay (Part 1 Of 3):

Test 8A: Repairing -- Excess Decay (Part 2 Of 3):

Test 8A: Repairing -- Excess Decay (Part 3 Of 3):

Modulator Schematics:

Front Wheel Speed Sensor:

Rear Wheel Speed Sensor:

NOTE: You must perform Test 1A, before proceeding with this test.

EXCESS DECAY

When Its Monitored
During Antilock Brake System (ABS) cycling if any two decay valves are on for more than 4.5 seconds.

Set Condition
If, during ABS cycling, any two decay valves are commanded to remain on for more than the set time, this trouble code is set. The ABS warning lamp is illuminated until the vehicle speed is less than 3 miles per hour. Only the rear ABS is allowed to ensure stability.

Possible Causes:
^ Modulator trouble code/solenoid valve problem
^ Wheel Speed Sensor trouble code
^ Hydroplaning
^ Very long stops on ice
^ Incorrect tone wheels
^ Incorrect Controller Antilock Brake (CAB)
^ Excessively worn tires
^ Leaving the clutch engaged during braking on ice at low speeds
^ Wheel speed sensor pick-up end contaminated or damaged
^ Very cold weather causing slow decay rates