B1486

Code

Other B — Body

Brake Pedal Input Circuit Ground Short

Brand: Other

Type: B — Body

Views: UK: 28 EN: 38 RU: 36

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Damaged wiring harness (chafed, pinched, or crushed) causing insulation damage and contact with chassis ground
Corroded, bent, or contaminated brake pedal switch connector or terminals
Failed brake pedal position switch or sensor with internal short
Aftermarket accessories or recent repairs that disturbed brake circuit wiring
Poor ground or misrouted ground splice causing unintended grounding of the signal circuit

Brake lamp behavior anomalies (constant on, off, or intermittent)
Cruise control may be disabled or disengage immediately
ABS or traction control may report faults or behave erratically (depending on vehicle)
Brake-related warning light illuminated, and stored B1486 code
Possible inability to shift out of park (on some vehicles with shift interlock tied to brake input)

Read and record all stored codes and freeze-frame data with a scan tool; note whether the code is current or historic
Inspect brake pedal switch and connector for corrosion, damage, or loose pins
Visually trace wiring from brake pedal switch toward the module/ECU looking for chafed areas, pinched spots, or signs of recent repair
Wiggle the harness and connector while watching live data or DTC status to try to reproduce the fault
Disconnect the brake pedal switch connector and observe whether the code clears or changes (consult vehicle-specific behavior before disconnecting)

Typical expected: open/nominal signal when released and switched state (0–5 V or signal referenced to battery/ground depending on design). Exact voltage depends on vehicle — consult wiring diagram
Short-to-ground symptom: signal voltage reads ≈0 V or continuity to chassis ground when circuit should be open
Continuity: with ignition OFF, check for continuity between the signal wire and chassis ground — short present if near 0 Ω (subject to presence of switch)
Resistance of a healthy switch (if applicable): open or specified low resistance when closed; check vehicle service data for exact values

Retrieve DTC details and any related codes. Note whether fault is pending or active.
Inspect the brake pedal switch and connector for physical damage, corrosion, or loose terminals. Repair or replace connector as required.
With ignition ON (engine off), backprobe the brake input signal wire at the pedal switch and observe voltage or switch state on a scan tool. Compare to expected values in service data.
If signal reads ~0 V (short to ground), disconnect the switch connector. If the code clears or signal changes, suspect wiring or switch.
Perform a continuity test between the signal wire (with connector disconnected) and chassis ground. If continuity exists, isolate sections of harness to locate short: disconnect intermediate connectors and repeat continuity checks until the shorted segment is found.
Inspect harness routing where it passes through pinch points (firewall, bracketry, steering column, pedal assembly) and repair any chafed or exposed wiring with proper splicing/protection.
If wiring checks good, replace the brake pedal switch and re-test.
After repairs, clear codes and perform functional test: operate brake pedal while monitoring live data and confirm no return of B1486 during normal use and road test if required.
Advise retest after any aftermarket wiring or trailer harness repairs and ensure grounds and splices are secure.

Chafed wire near pedal bracket or steering column contacts chassis metal
Corroded connector at the brake pedal switch allowing conductive path to ground
Failed brake light/brake switch with internal short to ground
Improperly installed trailer wiring or alarm/remote start tapping into brake circuit