P0487 EGR Throttle Position Control Circuit (D6CC)

Component Location

P0487 EGR Throttle Position Control Circuit

General Description (P0487)

DC motor type EGR actuator which is controlled by EDU module operates the EGR valve directly. ECM performs EGR system feed back control with the information of measured mass air flow. (The role of AMS in diesel engine is different from gasoline engine. Fuel injection quantity is decided by MAFS signal in gasoline engine.)

When the amount of EGR gas(contains no oxygen) flowing into combustion chamber increases, the air passing through MAFS(contains oxygen) decreases. Thus, with the output signal change of AMS accompanied by EGR actuator actuation, ECM determines the amount of recirculated EGR gas quantity.

DTC Description (P0487)

If EGR actuator circuit is open for more than 60 seconds, ECM judge this as a fault and DTC is set. The possible cause may be EDU-EGR harness open circuit, EGR DC motor problem. In case of fail safe, it is impossible to control EGR system and engine output is restricted. The vehicle can be driven but lack of engine power and black smoke may occur.

Item	Detecting Condition			Possible Cause
DTC Strategy	• Current monitoring			•EGR DC motor harness open •EGR DC motor
Enable Conditions	• At driving
Threshold Value	• EGR actuator not working
Diagnosis Time	• Above 60 sec.
Fail Safe	Fuel Cut	No	• EGR control impossible•Engine output is restricted
	Fuel Limit	Yes
	MIL	Off

Specification

Specification : 2.1±0.3 Ω

Monitor Scantool Data

1. Connect scantool to Data Link Connector(DLC).
2. Warm up the engine to normal operating temperature.
3. Turn the electrical equipment and air conditioner off.
4. Monitor “Intake air and EGR valve” parameter on the scantool

Fig.1) EGR valve sensor data at idle
Fig.2) EGR valve sensor data at 1000 rpm
Fig.3) EGR valve sensor data at 2000 rpm
※ Diagnostic Aids
When lack of engine power occurs, intake system inspection is useful as a reference.
Check to be sure that EGR valve actual position is conversing the EGR position demand.

Terminal & Connector Inspection

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

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

3. Has a problem been found?

YES	Repair as necessary and then go to “Verification of Vehicle Repair” procedure.
NO	Go to “Power Circuit Inspection” procedure.

Power Circuit Inspection

1. EGR DC motor – EDU Circuit Open Inspection
(1) IG “OFF”, and set the start safety switch ON.
(2) Disconnect the EGR motor connector and EDU module connector.
(3) Measure resistance between terminal 5 of the EGR motor harness connector and terminal 11 of the EDU module connector.
(4) Measure resistance between terminal 6 of the EGR motor harness connector and terminal 10 of the EDU module connector.
(5) Measure resistance between terminal 7 of the EGR motor harness connector and terminal 9 of the EDU module connector.

Specification: Infinite

(6) Is the resistance measured within specification?

YES	Go to “Component Inspection” procedure.
NO	Repair open in circuit and then go to “Verification of Vehicle Repair” procedure.

Component Inspection

1. EGR DC Motor Visual Inspection
(1) IG “OFF”, and set the start safety switch ON.
(2) Disconnect the EGR DC motor connector.
(3) Carefully check the EGR DC motor connector for corrosion or damage.
(4) Has a problem found?

YES	Repair as necessary and go to “Verification of Vehicle Repair” procedure.
NO	Go to “EGR DC Motor Resistance Inspection” procedure.

2. EGR DC Motor Resistance Inspection
(1) IG “OFF”, and set the start safety switch ON.
(2) Disconnect the EGR DC motor connector.
(3) Measure resistance between terminals of EGR DC motor connector.

Specification : 2.1±0.3 Ω

(4) Is the resistance measured within specification?

YES	Go to “Verification of Vehicle Repair” procedure
NO	Replace the EGR DC motor and 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 the DTC.
3. Operate the vehicle within DTC enable conditions in General Information.
4. Are any DTCs present?

YES	Go to the applicable DTC procedure.
NO	System is performing to specification at this time.

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Trouble Code