C1237

C1237

Component Location:

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

DTC Description
The failure is detected if the pressure sensor signal noise is out of normal range, or the pressure sensor signal is changed abnormally.
In spite of no brake switch signal, master cylinder pressure exceeds 20bar when brake switch is normal.

DTC Detecting Condition:

Schematic Diagram:

Signal Waveform:

Monitor Scantool Data
1. Connect scantool to Data Link Connector (DLC)
2. Ignition "ON" & Engine "ON".
3. Press the brake pedal.
4. Monitor the "Pressure Sensor" parameter on the Scantool.

Specification : Approx. 60bar -150bar (There is difference in displayed parameter according to braking force)






5. Is parameter displayed within specifications?

YES
a. Fault is intermittent caused by poor connection in pressure sensor harness and/or HECU's connector or was repaired and HECU memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.

NO
a. Go to "W/Harness Inspection" procedure.

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

NO
a. Go to "Signal Circuit Inspection" procedure.

Signal Circuit Inspection
1. Ignition "ON" & Engine "OFF".
2. Measure voltage between terminal "12" of the HECU harness connector and chassis ground.

Specification : 0.2 ± 0.1 V - 4.8 ± 0.1V

0.2 ± 0.1 V (in case of no braking)






3. Is the measured voltage, waveform within specifications (isn't there excessive variation in waveform)?

YES
a. 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.

NO
a. Check for open or short in pressure sensor harness between terminal "1" of the pressure sensor harness connector and terminal "12" of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
b. If OK, Go to "Component Inspection" procedure.

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

Specification : 0.2 ± 0.1 V - 4.8 ± 0.1 V






4. Is the measured voltage, waveform within specifications?

YES
a. Fault is intermittent caused by poor connection in pressure sensor harness and/or HECU's connector or was repaired and HECU memory was not cleared. Go to "Verification of vehicle Repair" procedure.

NO
a. 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
a. Go to the applicable troubleshooting procedure.

NO
a. System performing to specification at this time.