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COMPONENT LOCATION

GENERAL DESCRIPTION

The PCM provides ground to one side of the coil of the main relay and the other side is connected to the battery. The PCM monitors battery voltage and the voltage after the main relay.

DTC DESCRIPTION

Checking the contolling state of main relay every 10 sec. under detecting condition, if open or short in the circuit is detected for more than 5 sec., PCM sets P0685.

DTC DETECTING CONDITION

Item	Detecting Condition	Possible cause
DTC Strategy	● Detects a short to ground, to battery or open circuit on the main relay	● Poor Connection ● Open or short in control circuit. ● Faulty Main Relay ● Faulty PCM
EnableConditions	● Engine Running ● 11V ≤ Ignition Voltage ≤ 16V
Threshold value	● Open or Short in circuit
DiagnosisTime	● Contineous (More than 5sec. Failure for every 10 sec. test)
MIL On Condition	● DTC only (NO MIL ON)

※ If Main relay has a fault(ex. Open) while the engine is running, the DTCs,P0638/P0685/P1295/P2106, can happen at the same time.

＜DTC Name＞

P0638 Throttle Actuator Control Range/Performance(Bank 1)

P0685 PCM/PCM Power Relay Control Circuit /Open

P1295 Throttle Actuator Control System - Power Management

P2106 Throttle Actuator Control System - Forced Limited Power

SPECIFICATION

Coil Resistance

70Ω ~ 120Ω

SCHEMATIC DIAGRAM

MONITOR DTC STATUS

Check DTC Status

(1)

Connect scantool to Data Link Connector(DLC).

(2)

IG "ON".

(3)

Select "DTC" button, and then Press "DTC Status" to check DTC's information from the DTCs menu.

(4)

Read "DTC Status" parameter.

(5)

Is parameter displayed "Present fault"?

▶ Go to "Terminal and connector inspection" procedure.

▶ Fault is intermittent caused by poor contact in the sensor's and/or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, ending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of Vehicle Repair" procedure.

TERMINAL AND CONNECTOR INSPECTION

Many malfunctions in the electrical system are caused by poor harness and terminal condition. 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.

Has a problem been found?

▶ Repair as necessary and go to "Verification of Vehicle Repair" procedure

▶ Go to " Power Circuit Inspection " procedure.

POWER CIRCUIT INSEPCTION

■ Check voltage

IG "OFF".

Disconnect the main relay.

IG "ON" and ENG "OFF"

Measure the voltage between power supply terminals of main relay harness connector and chassis ground.

Specification : B+

Is the measured voltage within specification ?

▶ Go to "Control Circuit Inspecition" procedure.

▶ Check fuse between battery and main relay is disconnected.

▶ Repair or replace open or short in harness and then go to "Verification of Vehicle Repair" procedure.

CONTROL CIRCUIT INSPECTION

■ Check short in harness

IG "OFF".

Disconnect main relay and PCM connector.

Measure the resistance between control terminal of main relay harness connector and chasses ground.

Specification : Infinite

Is the measured resistance within specification ?

▶ Go to "Check open in harness" as follows.

▶ Repair or replace as necessary and then go to " Verification of Vehicle Repair" procedure.

■ Check open in harness

IG "OFF".

Disconnect main relay and PCM connector.

Measure the resistance between control terminal of main relay harness connector and main relay control terminal of PCM harness connector.

Specification : Approx. below 1Ω

Is the measured resistance within specifications ?

▶ Go to "Component Inspection" procedure.

▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair" procedure.

COMPONENT INSPECTION

■ Check Main relay

IG "OFF".

Disconnect the main relay.

Measure the resistance between battery power supply and control terminals of main relay.(Measurement "A")

Measure the resistance between battery power supply and power supply to PCM terminals of main relay.(Measurement "B")

Specification : 70 ~ 120Ω

Terminal	continuity
Battery power supply - Power supply to PCM	NO
Battery power supply - Main relay control	YES (Approx. 70Ω ~ 120Ω)

Is the measured reisistance within specification ?

▶ ubstitute with a known - good PCM and check for proper operation. If the problem is corrected, replace PCM and go to "Verification of Vehicle Repair" procedure.

note

There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. Before or after testing PCM on the vehicle, use this function to reuse the PCM on the others.

▶ Substitute with a known - good Main Relay and check for proper operation. If the problem is corrected, replace Main Relay 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.

Connect scantool and select "DTC" button.

Press "DTC Status" button and confirm that "DTC Readiness Flag" indicates "Completed". If not, drive the vehicle within conditions noted in the freeze frame data or enable conditions

Read "DTC Status" parameter

Is parameter displayed "History(Not Present) fault"?

▶ System performing to specification at this time. Clear the DTC

▶ Go to the applicable troubleshooting procedure.