3.
Monitor the "BATTERY VOLTAGE" parameter on the scantool.
Specification : Above. 9±0.5V
Fig 1) Test Condition : Ignition "ON" & Engine "ON".
Normal Data
The ABS ECU(Electronic Control Unit) checks the battery voltage and alternator output voltage to determine, as a safety issue, whether the ABS system can operate normally or not.
The normal battery voltage range is essential for controlling the ABS system as intended.
The ABS ECU monitors the battery voltage and alternator output voltage by reading the value of voltage.
When the voltage is lower than the expected normal value, this code is set.
The ABS/ESP functions are prohibited and the EBD function is allowed on LOW VOLTAGE CONDITION, the ABS/EBD/ESP functions are prohibited on UNDER VOLTAGE CONDITION.
If the voltage recovers, to within normal operating ranges, then the controller returns to normal operations as well.
Item | Detecting Condition | Possible cause | |
DTC Strategy | ● Battery Voltage Monitoring | ● Poor connection in power supply circuit (IGN+) ● Faulty HECU ● Discharge of electricity | |
Case1 (Low voltage) | Enable Conditions | ● When Vign<9.5V±0.5V is continued for 500msec during Vref >= 7Km/h. ● When Vign<8.5V±0.5V is continued for 500msec during Vref < 7Km/h or ABS/ESP(ESC) control. - If IGN voltage is recovered to normal operating voltage, the system recovers to normal state. | |
Fail Safe | ● Outside the ABS control cycle : Inhibit the ABS/ESP control, allow the EBD control , The ABS/ESP warning lamps are activated, When the voltage recovers the normal operating range, erase the error code. ● Inside the ABS control cycle : Inhibit the ABS/ESP control. The ABS/ESP warning lamps are activated. Althought the voltage recovers the normal operating range, warning lamps are illuminated and the error code is always stored. | ||
Case2 (Under voltage) | Enable Conditions | ● When Vign<7.2V±0.5V is continued for 56msec. - If IGN voltage is recovered to normal operating voltage, the system recovers to normal state. | |
Fail Safe | ● The ABS/EBD/ESP functions are inhibited. ● The ABS/EBD/ESP warning lamps are activated. | ||
Normal Voltage Range | ENG "ON" |
10V ~ 16V |
Connect scantool to Data Link Connector(DLC)
Ignition "ON" & Engine "ON".
Monitor the "BATTERY VOLTAGE" parameter on the scantool.
Specification : Above. 9±0.5V
Fig 1) Test Condition : Ignition "ON" & Engine "ON".
Normal Data
Is parameter displayed within specifications?
 | ▶ Fault is intermittent caused by poor connection in power harness (IGN+) 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. |
 | ▶ Go to "Terminal and Connector Inspection" procedure. |
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.
Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
Has a problem been found?
| ▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure. |
| ▶ Go to "Alternator Output Voltage Inspection" procedure. |
Ignition "ON" & Engine "ON".
Maintain ENG RPM 2,500RPM over 2 minutes.
Measure voltage between the battery terminal(+) and the battery terminal(-).
Specification : Above. 9±0.5V
Is the measured value within specifications?
| ▶ Go to "Power Circuit Inspection" procedure. |
| ▶ Check that the tension of drive belt, ENG RPM, fuse, terminal of battery, all terminals of alternator are in good condition and Check for damaged harness and poor connection between alternator and battery. If OK repair or replace alternator and then go to "Verification of vehicle Repair" procedure. |
Ignition "ON" & Engine "OFF".
Measure voltage between the battery terminal(+) and power terminal of the HECU harness connector.
Specification : Approx. below 0.2V
Is the measured value within specifications?
| ▶ Go to "Ground Circuit Inspection" procedure. |
| ▶ Check for open or blown ABS fuse referring to "Circuit Diagram". Repair open or short in power circuit between battery and HECU harness connector and then go to "Verification of vehicle Repair" procedure. |
Ignition "OFF" & Engine "OFF".
Disconnect HECU connector.
Measure resistance between ground terminal of the HECU harness connector and chassis ground.
Specification : Approx. below 1Ω
Is the measured value within specifications?
| ▶ 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. |
| ▶ Repair open or short in ground circuit between HECU harness connector and chassis ground and then go to "Verification of vehicle Repair" procedure. |
After a repair, it is essential to verify that the fault has been corrected.
Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode
Using a scantool, Clear DTC.
Operate the vehicle within DTC Detecting Condition in General Information.
Using a scantool, Check DTC present.
Are any DTCs present ?
| ▶ Go to the applicable troubleshooting procedure. |
| ▶ System performing to specification at this time. |
