P0504 on Chevrolet
Brake Switch "A"/"B" Correlation
P0504 on Chevrolet vehicles indicates brake switch "a"/"b" correlation. Au7o has documented this code across 2 Chevrolet models — most commonly on Colorado, Malibu. Most vehicles use two independent brake switch signals (a normally-open and a normally-closed circuit, switch A and switch B). The PCM compares them and expects them to change state together when the brake pedal is pressed. P0504 sets when the two signals disagree (do not correlate), indicating one switch or circuit is faulty. Typical repair costs on Chevrolet range from $30 to $180, depending on the specific model and root cause.
Common Causes of P0504
- •Failed brake light switch
- •Misadjusted brake switch (plunger gap)
- •Wiring/connector fault on one of the two brake switch circuits
- •Blown brake-circuit fuse affecting one signal
- •Faulty PCM input
P0504 on Chevrolet by Model
Chevrolet Colorado(1 issue)
- Brake Light Switch Failure Causing Stuck Brake Lamps, Shift Interlock Problems, or Cruise Control Malfunction2004-2012
The brake lamp switch at the pedal is a known weak point on first-generation Colorado trucks. Owners report brake lights staying on, not coming on reliably, inability to shift out of park, or cruise control dropping out unexpectedly. Because the switch feeds several circuits, a single failure can create multiple confusing symptoms.
Chevrolet Malibu(1 issue)
- NHTSA Recall 14V252000: Body Control Module Connection Resistance Disturbs Brake Apply Sensor Circuit2004-2012
GM recalled 2004-2012 Chevrolet Malibu sedans (built May 16, 2003 through October 11, 2012) because increased electrical resistance in the Body Control Module (BCM) connection can cause voltage fluctuations in the Brake Apply Sensor (BAS) circuit. NHTSA's record states those fluctuations can cause the brake lights to behave incorrectly, among other conditions. This is a connector/wiring-interface defect at the BCM rather than a worn brake pedal switch, so a Malibu can exhibit the fault even if the brake switch itself has already been serviced. The campaign covered 2,440,524 vehicles in total across every model included in it (Malibu, Malibu Maxx, Pontiac G6 and Saturn Aura) — that figure is campaign-wide and is not a count of Malibus. NHTSA states that any of these failure conditions increases the risk of a crash.
Looking for P0504 on a different make?
View P0504 across all makes →Frequently Asked Questions
What does P0504 mean on Chevrolet?▼
P0504 stands for "Brake Switch "A"/"B" Correlation." Most vehicles use two independent brake switch signals (a normally-open and a normally-closed circuit, switch A and switch B). The PCM compares them and expects them to change state together when the brake pedal is pressed. P0504 sets when the two signals disagree (do not correlate), indicating one switch or circuit is faulty. On Chevrolet specifically, this code is documented across 2 models.
What causes P0504 on Chevrolet vehicles?▼
Common causes on Chevrolet: Failed brake light switch, Misadjusted brake switch (plunger gap), Wiring/connector fault on one of the two brake switch circuits, Blown brake-circuit fuse affecting one signal, Faulty PCM input. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0504 on a Chevrolet?▼
Repair costs on Chevrolet range from $30 to $180, depending on the specific model and root cause.
Which Chevrolet models have P0504 documented?▼
Au7o has documented P0504 on 2 Chevrolet models: Colorado, Malibu.