P0504 on Nissan
Brake Switch "A"/"B" Correlation
P0504 on Nissan vehicles indicates brake switch "a"/"b" correlation. Au7o has documented this code across 1 Nissan model — most commonly on Sentra. 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.
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 Nissan by Model
Nissan Sentra(1 issue)
- Brake Light Switch Failure - No Brake Lights / Won't Shift From Park (Recall PM971 / 21V-135)2016-2019
The stop-lamp (brake light) switch becomes contaminated by silicone off-gassing from grease used on nearby components. Electrical arcing oxidizes the contacts and builds up silicon dioxide, opening the circuit. The result is brake lights that do not illuminate (a rear-end-collision hazard) and, because the same switch signals the shift interlock, an inability to shift the transmission out of Park. Nissan recalled 807,376 Sentras under campaign PM971 (NHTSA 21V-135).
Looking for P0504 on a different make?
View P0504 across all makes →Frequently Asked Questions
What does P0504 mean on Nissan?▼
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 Nissan specifically, this code is documented across 1 model.
What causes P0504 on Nissan vehicles?▼
Common causes on Nissan: 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 Nissan?▼
Repair costs vary widely depending on the root cause and specific Nissan model.
Which Nissan models have P0504 documented?▼
Au7o has documented P0504 on 1 Nissan model: Sentra.