- No Communication With the Anti-Lock Brake System (ABS) Module
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- Central junction box (CJB) fuse 23 (10A).
- Circuitry.
- ABS module.
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- Unable to Enter Self-Test
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- Anti-lock brake system (ABS) module.
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- Rear axle speed sensor indicator is damaged.
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- REMOVE rear sensor from the differential housing; INSPECT rear axle speed sensor indicator.
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- Front wheel speed sensor indicator is damaged.
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- INSPECT for damaged teeth. INSPECT both front tone rings.
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- Sensor output is out of sync.
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- Intermittent open or shorted sensor circuit.
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- Chafed wire insulation or pinched wire due to improper routing causing intermittent short.
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- INSPECT wiring harness from front sensor knuckle to the frame and from the rear axle to the frame for worn or chafed wire insulation.
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- Rear brake adjustment too tight.
- Linings are grabby.
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- ELIMINATE base brake system as cause of problem.
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- Hydraulic outlet (dump) valve.
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- Leaky inlet (isolation) valve during ABS (soft).
- Damp or contaminated rear brake shoe linings, stuck/leaking wheel cylinder, overadjusted rear brakes.
- Binding parking brake.
- Leaking rear axle seal.
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- Stuck inlet (isolation) valve (hard brake pedal) or leaky outlet (dump) valve (soft brake pedal).
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- Hydraulic leak in brake line or hose, fitting, master cylinder, wheel cylinder, or caliper (soft brake pedal).
- Air in brake system (soft brake pedal).
- Little or no vacuum boost (hard brake pedal).
- Stuck or inoperative wheel cylinder or caliper (hard brake pedal).
- Pinched or crimped brake line or hose (hard brake pedal).
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- Lack of Deceleration During Medium/Hard Brake Application
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- Stuck shut inlet (isolation) valve or leaky outlet (dump) valve (rear axle only).
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- Hydraulic leak in brake line or hose, fitting, master cylinder, wheel cylinder, or caliper.
- Air in brake system.
- Little or no vacuum boost.
- Stuck or inoperative wheel cylinder or caliper.
- Ineffective brake shoe or pad linings.
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- Vehicle Pulls During Braking
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- Improperly adjusted rear brake.
- Frozen or binding caliper (one side of vehicle).
- Uneven brake pad or shoe wear.
- Pinched or crimped brake line or hose.
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- Fully or partially blocked front inlet (isolation) valve.
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- ABS Warning Lamp On With System Pass
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- ABS warning lamp circuit open.
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- DISCONNECT 25-pin connector C146 from ABS module. Using a jumper wire, GROUND pin 15, circuit 603 (DG). If lamp is off, INSTALL a new ABS module. REFER to ANTI-LOCK BRAKE SYSTEM (ABS) MODULE in this article. If lamp remains on, REPAIR circuit 603 (DG).
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- Yellow ABS Warning Indicator Does Not Self-Check
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- Circuitry.
- Yellow ABS warning indicator bulb.
- ABS module.
- Instrument cluster.
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- Soft or Excessive Pedal Travel
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- Hydraulic leak in brake line, hose fitting, master cylinder, or caliper (soft brake pedal)
- Air in brake system (soft brake pedal)
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- Hydraulic control unit (HCU).
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