COMPONENT LOCATION
General Description

There is no hardware difference of the HECU according to the vehicle's specification, just software is changed by the vehicle parameter used for ESP control. The HECU stores a classified varient code value according to the received data(a kind of engine, engine displacement, a kind of T/M). After then the HECU read a various parameter according to the stored varient value in the memory to use for the ESP control.

DTC Description

The HECU checks the varient code after ignition. If a inappropriate varient code is detected or there is no varient code, a fault is detected.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC Strategy

Internal monitoring

Faulty HECU

Replacement of EMS, T/M ECU

Monitoring Period

Once during startup.

Enable Conditions

During intialization, there is no inputed valid varient code.

The EEPROM didn’t have variant coed.

Receieved variant code is invalid.

There is a difference between pre-inputted variant code and re-inputted variant code.

Fail Safe

The ABS/EBD/ESP functions are inhibited.

The ABS/EBD/ESP warning lamps are activated.

Monitor Scantool Data
Variant Code
1.

Check for improper installation of EMS/TCU/ESP.

2.

Connect scantool to Data Link Connector(DLC).

3.

Ignition "ON".

4.

Go in Anti-Lock brake system (figure 1).

5.

Perform variant code.

6.

Disconnect scantool.

7.

Ignition "OFF" and then ignition "ON". Go to "Component Inspection"Procedure.

Component Inspection
1.

Ignition "OFF".

2.

Engine "ON".

3.

Does warning lamp remain On?

▶ 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 the applicable troubleshooting 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.

Are any DTCs present ?

▶ Go to the applicable troubleshooting procedure.

▶ System performing to specification at this time.

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