Failure Diagnosis

1. In principle, ESC and TCS controls are prohibited in case of ABS failure.
2. When ESC or TCS fails, only the failed system control is prohibited.
3. However, when the solenoid valve relay should be turned off in case of ESC failure, refer to the ABS fail-safe.
4. Information on ABS fail-safe is identical to the fail-safe in systems where ESC is not installed.

MEMORY OF FAIL CODE 

1. It keeps the code as far as the backup lamp power is connected. (O)
2. It keeps the code as long as the HCU power is on. (X)

FAILURE CHECKUP 

1. Initial checkup is performed immediately after the HECU power on.
2. Valve relay checkup is performed immediately after the IG2 ON.
3. It executes the checkup all the time while the IG2 power is on.
4. Initial checkup is made in the following cases.
   1. When no failure is detected
   2. When ABS and ESC are not in control.
   3. Initial checkup is not made after ECU power on.
   4. If the vehicle speed is over 5 mph (8 km/h) when the brake lamp switch is off.
   5. When the vehicle speed is over 24.8 mph (40 km/h).
5. Though, it keeps on checkup even if the brake lamp switch is on.
6. When performing ABS or ESC control before the initial checkup, stop the initial checkup and wait for the HECU power input again.
7. Judge failure in the following cases.
   1. When the power is normal.
   2. From the point in which the vehicle speed reaches 4.9 mph (8 km/h) after HECU power on.

COUNTERMEASURES IN FAIL 

1. Shut the system down and perform the following actions and wait for HECU power OFF.
2. Turn the valve relay off.
3. Do not perform any ABS/TCS/ESC functions until normal operating condition is restored.

WARNING LAMP ON 

1. ABS warning lamp turns on when ABS is malfunctioning.
2. ESC operation lamp turns on when ESC is malfunctioning.

When power voltage and valve relay voltage are abnormal, input/output related failure judgment is not made.