C1237

C1237

Component Location:

General Description
The two pressure sensors,installed in the master cylinder, sense the brake oil pressure to judge driver's brake intention when ESC is operating.

DTC Description
The pressure sensor signals are read via A/D converter once per loop.
Each unfiltered input signal value is monitored to be in the range of 5% sensor supply voltage < input signal value < 95% sensor supply voltage.
There is no restriction of the pressure sensor output voltage if the specified operating range is reached or exceeded.
The signal can therefore reach into a fault area without any fault being present in the sensor.
A failure is detected if the output signal stays in one of the fault areas longer than the monitoring time.

DTC Detecting Condition:

Specification:

Schematic Diagram:

Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness (es) and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?

YES - Repair as necessary and then go to "Verification of Vehicle Repair" procedure.

NO - Go to "Signal Circuit Inspection" procedure.


Signal Circuit Inspection
1. Ignition "ON" & Engine "OFF".
2. Put and release the brake pedal several times.
3. Measure voltage, waveform between terminal "20,23" of the HECU harness connector and chassis ground.

Specification : 0.5 V - 4.4 V
Approx. 0.5 V (in case of no braking)






4. Is the measured voltage within specifications?

YES - Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.

NO
- Check for open or short in pressure sensor harness between terminal "1" of the pressure sensor A,B harness connector and terminal "20,23" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
- Go to "Component Inspection" procedure.

Component Inspection
1. Ignition "ON" & Engine "OFF".
2. Put and release the brake pedal several times.
3. Measure voltage, waveform between terminal "1" of the pressure sensor (primary and secondary) harness connector and chassis ground.

Specification : 0.5 V - 4.4 V
Approx. 0.5 V (in case of no braking)






4. Is the measured voltage, waveform within specifications?

YES - Fault is intermittent caused by faulty HECU or was repaired and HECU memory was not cleared. go to "Verification of Vehicle Repair" procedure.

NO - Substitute with a known-good pressure sensor and check for proper operation. If problem is corrected, replace pressure sensor and then go to "Verification of Vehicle Repair" procedure.

Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes (DTCs)" mode
2. Using a Scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Are any DTCs present?

YES - Go to the applicable troubleshooting procedure.

NO - System performing to specification at this time.