ESP

C2227

Component Location:

General Description
The instantaneous brake disc temperature will be computed at the wheel brakes of all driven wheels with the following inputs : (1. vehicle and brake constants, 2. The vehicle speed, 3. all wheel speeds, 4. The computed brake pressure during active brake torque control, 5. The vehicle deceleration during braking with and without ABS control.) A failure is detected if the computed brake disc temperature exceeds 500 °C at a minimum one wheel brake. The DTCs remain deactivated until the computed brake disc temperature of all wheel brakes drops below 350 °C. With the ignition turned off, the ECU is supplied with energy via power supply voltage until the computed brake temperature at the driven wheels drops below 70 °C.

DTC Description
If the HECU decides that the Disc is over-heated (above 500 °C), then it turns the TCS lamp ON and inhibits DTCs operation to prevent overheating of the disc.
If the calculated temperature becomes lower than specified value (approx. 350 °C), then the HECU turns the TCS lamp OFF and operates the DTCs again.

DTC Detecting Condition:

Component Inspection
1. Wait till the brake discs cool down sufficiently.
2. Ignition "OFF".
3. Ignition "ON".
4. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode
5. Using a scantool, Clear DTC.
6. Select "Diagnostic Trouble Codes (DTCs)" mode again.
7. Are any DTCs present ?

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 caused by Faulty HECU or was repaired and HECU memory was not cleared.
- The DTC code can be set by excessive TCS control in normal system status. 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.