Brake System > ESC(Electronic Stability Control) System

Component Location

General Description

The HECU send requirement data, such as Torque reduction, the number of fuel cut cylinders, and ESC control requests, to the Engine PCM(ECM & TCM) through CAN bus line.

The Engine PCM(ECM) performs fuel cut functions according to requests from the HECU and retards ignition timing by torque reduction requests.

The PCM(TCM) maintains current gear positions during ESC control time, in order not to increase power which causes a Kickdown shift.

DTC Description

The HECU checks the CAN RAM for normal TCS control, and sets this code if a CAN RAM malfunction is detected.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC
Strategy

•	CAN RAM monitoring

•	Faulty HECU

Enable
Conditions

•	CAN Hardware failure.

Fail Safe

•	Inhibit the ESC control and allow the ABS/EBD control.

•	The ESC warning lamp is activated.

Schematic 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 and then go to "Verification Of Vehicle Repair" procedure.
	▶ Go to "Component Inspection" procedure.

Component Circuit Inspection

1.	Ignition "OFF" & Engine "OFF".

2.	Ignition "ON" & Engine "OFF".

3.	Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode.

4.	Using a scantool, Clear DTC.

5.	Select "Diagnostic Trouble Codes(DTCs)" mode again.

Are any DTCs present ?

	▶ 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.
	▶ Fault is intermittent caused by faulty HECU or was repaired and HECU memory was not cleared. Go to "Verification Of Vehicle Repair" procedure.

Verification of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.

1.	Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode.

2.	Using a scantool, Clear DTC.

3.	Operate the vehicle within DTC Detecting Condition in General Information.

4.	Using a scantool, Check DTC present.

Are any DTCs present ?

	▶ Go to the applicable troubleshooting procedure.
	▶ System performing to specification at this time.