PCM sets DTC P0504 if the PCM detects signal of the brake warning lamp and brake switch do not correlate within the predetermined time.
| Item | Detecting Condition | Possible Cause | 
| DTC Strategy | 
										•
									 Plausibility check between Brake Light Switch(BLS) and Brake Test Switch(BTS) | 1. Open or short circuit in harness 2. Poor connection or damaged harness 3. Faulty brake warning lamp or brake test switch | 
| Enable Conditions | 
										•
									 Engine running | |
| Threshold Value | 
										•
									 Time between brake light switch and brake test switch do not correlate longer than > 10 sec. | |
| Diagnostic Time | 
										•
									 12 times brake pedal activation | |
| MIL On Condition | 
										•
									 - |