C2402 ABS PUMP Motor Failure - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

The ABS ECU supplies battery power to the electric motor by way of a motor relay which is controlled by the Electronic Control Unit(ECU).

The electric motor pump supplies hydraulic pressure to all wheel brake calipers by operating the piston inside the pump.

DTC DESCRIPTION

The ABS ECU monitors the pump motor relay or fuse open, open or short in motor or motor lock and then sets this code if a malfunction is detected.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible cause

DTC Strategy

Battery Voltage Monitoring

Open or short of power supply circuit

Blown fuse

Faulty HECU

Case1
(Motor Relay Open orMotor Short to GND)

Enable
Conditions

If the motor relay is switched ON and motor voltage < (IGN voltage – 4V±0.5V) continued for 49msec, the failure is detected.

Case2
(Motor Lock)

Enable
Conditions

After motor relay is switched OFF, VMR is measured. If the time which VMR > 1±0.1V is less than evaluation time, recheck is performed again for a maximum of three times.

When VMR is not normal even on the third recheck, the controller recognizes it as failure.

Case3
(Motor Open, Motor Short to BATT)

Enable
Conditions

After 1.8sec from the time that motor relay is switched OFF, VMR > 4±0.5V continued for 1.8sec, the failure is detected.

Case4
(Motor Fuse Open)

Enable
Conditions

If the motor relay is switched OFF and VMRP (Motor power supply voltage) < 4±0.5V continued for 1sec, the failure is detected.

Fail Safe

ABS/ESP functions are inhibited, EBD function is allowed and the ABS/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

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