Brake System

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. If pressure of master cylinder is applied to pressure sensor, the strain of the piezo element is changed and then the resistance of bridge circuit is changed according to changed strain. Therefore this changed resistance changes output voltage of bridge circuit and output voltage changes linearly. The sensor output is a analog signal in proportion to supply voltage, and the HECU recognizes a pressure value according to signal ratio about supply voltage.

DTC Description

Each unfiltered input signal voltage is monitored to be in the range of 0.2 V ± 0.1 V < input signal voltage < 4.8 V ± 0.1 V. A failure is detected if the output signal value is out of specified range for more than 1s or pressure sensor self test form is against to specification during self test.

DTC Detecting Condition





Terminal and Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness(es) and terminal conditions. 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 "Power Circuit Inspection" procedure.

Power Circuit Inspection

1. Ignition "ON" & Engine "OFF".
2. Measure voltage between terminal "2" of the pressure sensor harness connector and chassis ground.

Specification : Approx. 5 V





3. Is the measured voltage within specifications?
YES
> Go to "Ground Circuit Inspection" procedure.
NO
> Check for open or short to GND in pressure sensor harness between terminal "2" of the pressure sensor harness connector and terminal "37" of the ESC HECU harness connector. Repair as necessary and then go to "Verification Of Vehicle Repair" procedure. If OK, go to "Component Inspection" precedure.

Ground Circuit Inspection

1. Ignition "OFF".
2. Disconnect pressure sensor connector.
3. Measure resistance between terminal "3" of the pressure sensor harness connector and chassis ground.

Specification : Approx. below 1Ohms





4. Is the measured resistance within specifications?
YES
> Go to "Signal Circuit Inspection" procedure.
NO
> Check for open or short in pressure sensor harness between terminal "3" of the pressure sensor harness connector and terminal "28" of the ESC HECU harness connector. Repair as necessary and then go to "Verification Of Vehicle Repair" procedure.

Signal Circuit Inspection

1. Ignition "ON" & Engine "OFF".
2. 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





3. Is the measured resistance within specifications?
YES
> Go to "Component Inspection" procedure.
NO
> 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.
> If OK, 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.

Component Inspection

1. Ignition "OFF".
2. Engine "ON".
3. Start and drive vehicle in gear and maintain vehicle speed is approx. 40 km/h or more(24 mph or more) and then put on the brake three times.
4. Does warning lamp remain On?
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
> Fault is intermittent caused by open or short of pressure sensor harness, faulty pressure sensor and/or faulty HECU or was repaired and HECU memory was not cleared. Go to the applicable troubleshooting procedure.

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Using a scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information. (Start and drive vehicle in gear and maintain vehicle speed is approx. 40 km/h or more(24 mph or more) and then put on the brake three times.)
4. Are any DTCs present ?
YES
> Go to the applicable troubleshooting procedure.
NO
> System performing to specification at this time.