C2112 ABS Valve Relay Error - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

The HECU supplies battery power to all soleonid valves with a valve relay which is controlled by the Electronic Control UNIT(ECU).

The valve relay and all solenoid valves are installed inside the HECU ( Hydraulic and Electronic Control Unit ).

DTC DESCRIPTION

ABS ECU monitors voltage of the valve relay to check if ABS ECU can perform ABS control normally.

When the valve relay is switched to ON, the HECU will set this code if the solenoid drive voltage is below permissible voltage ranges for a period of time.

When the valve relay is switched to OFF, the HECU sets this code if the solenoid drive voltage is over the permissible voltage range for a period of time.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible cause

DTC Strategy

Voltage Monitoring

Open or short of power supply circuit

Blown fuse

Faulty HECU

Case1
(Open)

Enable
Conditions

If the valve relay is switched on and the reference voltage of valve relay < 5±0.5V continuously for 56ms, the failure is detected.

Case2
(Short or leakage)

Enable
Conditions

If the valve relay is switched off and voltage of valve relay > 6±0.5V or < 2.5±0.5V continuously for 56ms, the failure is detected.

Fail Safe

The ABS/EBD/ESP functions are inhibited.

The ABS/EBD/ESP warning lamps are activated.

DIAGNOSTIC CIRCUIT DIAGRAM

TERMINAL AND CONNECTOR INSPECTION

1.	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.

2.	Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.

Has a problem been found?

	▶ Repair as necessary.
	▶ Go to “Power Circuit Inspection” procedure.

POWER CIRCUIT INSPECTION

■ Open or Short Check

1.	Ignition “ON” & Engine “OFF”.

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

B+

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

1.	Ignition “OFF” & Engine “OFF”.

2.	Disconnect the 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
	▶ Repair open or short in ground circuit between HECU harness connector and chassis ground

New Videos on our YouTube Channel Every Week, Subscribe Now!

Related Posts