DTC C1237 Pressure Sensor-Signal: DTC Detecting Condition

DETECTING CONDITION AND POSSIBLE CAUSE

Item		Detecting Condition	Possible cause
Case 1	DTC Strategy	Signal Offset Monitoring	High frequency interferences at pressure sensor signal Faulty pressure sensor Faulty HECU
	Monitoring Period	Once per loop, but not checked if a checksum failure of the stored offset values is detected if the sensor supply voltage is out of range if the pressure sensor signal is out of range
	Enable Conditions	A failure is detected if the absolute value of the calculated pressure sensor signal offset is higher than 8.0 bar.
	Fail Safe	The TCS/ESC functions are deactivated. The ACC (Adaptive Cruise Control) function is deactivated. The TCS/ESC warning lamps are activated.
Case 2	DTC Strategy	Noise Monitoring
	Monitoring Period	Once per loop when no control cycle is active but not checked If the sensor signal is out of range, if a driver brake apply is detected if the HBA (Hydraulic Brake Assist) function is deactivated, during activated pump motor if the sensor supply voltage is out of range during diagnostics mode, (started after a signal settling time of 3.0 s after power-on reset or after a signal settling time of 0.5 s if the sensor supply voltage is valid again)
	Enable Conditions	A failure is detected if the value of integrated signal noise exceeds 195mV for 70-280ms depending on noise level.
	Fail Safe	The TCS/ESC functions are deactivated. The TCS/ESC warning lamps are activated.
Case3	DTC Strategy	Redundancy Monitoring
	Monitoring Period	Once per loop, but not checked if the sensor supply voltage is out of valid range if the pressure sensor signals are out of range after a pressure sensor failure is detected, (started after a signal settling time of 0.5 s if the sensor supply voltage is valid again)
	Enable Conditions	A failure is detected if the difference between both pressure sensor signals is continuously higher than 20 bar for 0.5s.
	Fail Safe	The TCS/ESC functions are deactivated. The ACC (Adaptive Cruise Control) function is deactivated. The TCS/ESC warning lamps are activated.