C1604 ECU Hardware Error - Automotive Repair Guides & Equipment

COMPONENT LOCATION

GENERAL DESCRIPTION

EPS CM monitors internal circuit to protect abnormal operation. This test includes hardware (MCU, RAM, ROM and so on) test.

DTC DESCRIPTION

EPS CM checks operating condition of H/W periodically. EPS CM sets this code and turns on warning lamp if there is a fault in H/W. At that time EPS CM inhibits EPS opreation.

DTC DETECTING CONDITION

Item

Detecting Condition

Possible cause

DTC Strategy

Check ECU H/W

Faulty MCU

Faulty memory

Enable conditions

IG ON

Threshold value

ECU H/W error occurs

Fail Safe

EPS warning lamp “ON”, EPS control is inhibited

Restoration conditions

Normal condition after IG on → off

TERMINAL AND CONNECTOR INSPECTION

1.	Many malfunctions in the electrical system are caused by poor harness and terminals. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.

2.	Thoroughly check all connectors (and connections) for looseness, bending, corrosion, contamination, deterioration, and/or damage.

Has a problem been found ?

	▶ Repair as necessary .
	▶ Go to “Component Inspection” procedure.

COMPONENT INSPECTION

1.	Ignition “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 steering column & EPS unit assembly check for proper operation. If problem is corrected, replace steering column & EPS unit assembly
	▶ Fault is intermittent and caused either by poor contact in connectors or wiring harness, or it has been repaired and EPS CM memory is not cleared yet.

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