Brake Switch Circuit

EBC 2
NAME OF CODE:
Brake Switch Circuit

SET CONDITION:
The following criteria must be met for this code to be detected.
1. Brake switch applied starting at initial ignition turn-on and remaining applied until 10 seconds has elapsed with the vehicle speed above 59 Km/h (37 mph)

THEORY OF OPERATION:
One of the inputs to the CAB is a switch whose output is normally low and which goes high when the brake pedal is depressed. A check on the integrity of this signal begins when the self test ends. The state of the brake switch signal is examined once every 5 ms. The first time the signal appears high, the brake pedal switch check is ended and subsequent antilock activity is enabled. If the pedal switch signal stays low continuously until a total of 10 seconds has accumulated after a vehicle speed exceeding 59 km/h (37 mph), DTC (81) Brake Switch Circuit Failure is set.

POSSIBLE CAUSES:
- Malfunctioning or misadjusted brake switch
- Brake switch circuit between the brake switch and CAB shorted to battery (12v)
- Brake switch circuit shorted to battery (1 2v) inside the CAB
- Brake pedal continuously depressed
- Open ground connection to service brake switch


EBC 325
NAME OF CODE:
Snake Switch Circuit

SET CONDITION:
The following criteria must be met for this code to be detected.
1. Vehicle speed greater than 24 Km/h (15 mph) and the brake pedal has not been released since ignition was first fumed on.
OR
2. ABS enabled for at least one second with the brake switch released and having no history of ever having been applied since ignition was first turned on.

THEORY OF OPERATION:
One of the inputs to the CAB is a switch whose output is normally low and which goes high when the brake pedal is depressed. A check on the integrity of this signal begins when the self test ends. The state of the brake switch signal is examined once every 5 ms. The first time the signal appears high, the brake pedal switch check is ended and subsequent antilock activity is enabled. If the pedal switch signal stays high continuously from the initial ignition start-up and after a vehicle speed exceeds 24 km/h (15 mph), (81) Brake Switch Circuit Failure is set. The DTC 8t can also be set it the system goes into an ABS mode but the CAB has not sensed the brake switch ever being applied

POSSIBLE CAUSES:
- Malfunctioning or misadjusted brake switch
- Brake switch circuit between the brake switch arid CAB shorted to battery (12v)
- Brake switch circuit shorted to battery (1 2v) inside the CAB
- Brake pedal continuously depressed
- Open ground connection to service brake switch