C1101 Battery Voltage High - Automotive Diagnosis

GENERAL DESCRIPTION

The ABS ECU(Electronic Control Unit) monitors the system (battery) voltage. The normal system voltage range is essential for controlling the ABS system as intended.

COMPONENT LOCATION

1. Battery

2. HECU

DTC DESCRIPTION

When the voltage is higher than the expected normal value, this code is set, and the ABS/EBD/ESP(ESC) functions are prohibited.

If the voltage recovers to within normal operating range, then the controller returns to normal operation as well.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible cause

DTC Strategy

Battery Voltage Monitoring

1.	Poor connection in power supply circuit (IGN+)

2.	Faulty Alterator

3.	Faulty HECU

Threshold Value

Battery voltage is higher than 17±0.5V for over 2 sec.

Battery voltage is higher than 19±0.5V for over 500 msec.

Fail Safe

The ABS/EBD/ESP(ESC) functions are inhibited

The ABS/EBD/ESP(ESC) warning lamps are activated

SPECIFICATION

Normal Voltage Range	ENG “ON”
	10V ~ 16V

TERMINAL AND CONNECTOR INSPECTION

1.	Many malfunctions in the electrical system are caused by poor harness(es) and terminals. 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.

Has a problem been found?

	▶ Repair as necessary
	▶ Verify presence of battery voltage codes in other ECUs (SRS, etc). ▶ If battery voltage codes are not present in other ECUs, go to “Power Circuit Inspection” procedure. ▶ If battery voltage codes are present in other ECUs, go to “Alternator Output Voltage Inspection” procedure.

ALTERNATOR OUTPUT VOLTAGE INSPECTION

■ Charging System Check

1.	IG “ON” & ENG “ON”.

2.	Maintain ENG RPM 2,500RPM over 2 minutes.

Measure voltage between the battery terminal(+) and the battery terminal(-).

Below. 17±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 .

POWER CIRCUIT INSPECTION

■ Open or Short Check

IG “ON”.

Measure voltage between the battery terminal(+) and power terminal of the HECU harness connector.

Approx. below 0.2V

Is the measured value within specifications?

	▶ Go to “Ground Circuit Inspection” procedure.
	▶ Check for open or blown fuse referring to “Circuit Diagram”. ▶ Repair open or short in power circuit between battery and HECU harness connector

GROUND CIRCUIT INSPECTION

■ Open or Short Check

IG “ON”.

2.	Disconnect HECU connector.

Measure resistance between ground terminal of the HECU harness connector and chassis ground.

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 .

※ In a case of replacing HECU, operate following functions

1) “Steering Angle Sensor Calibration” for steering angle sensor offset correction (refer to C1261) -ESP only

2) “Longitudinal Sensor Calibration” for Longitudinal sensor offset correction (refer to C1285) – ESP only

3) “Variant Coding” for 2WD/4WD type setting (refer to C1702)

▶ Repair open or short in ground circuit between HECU harness connector and chassis ground

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