Fuel System > Engine Control System > P2507 ECM/PCM power Input Signal Low

Component Location

General Description

When the ignition switch is turned "ON", battery voltage is applied from the battery to the PCM through the main relay. In case that the ignition switch is turned "OFF", the PCM is supplied with power through the battery power input line to control the basic operation of vehicle.

DTC Description

If the battery power input line has a problem, PCM sets P2507 and MIL(Malfunction Indication Lamp) turns on.

DTC Detecting Condition

Item

Detecting Condition

Possible cause

DTC Strategy

•	Monitor the battery power input line

•	Poor connection

•	Open or short to ground in line

•	Faulty PCM

Enable Conditions

•

Threshold value

•	Open or short to ground in line

Diagnosis Time

•	Continuous (More than 5 sec.failure for every 10 sec.test)

MIL On Condition

•	1 Driving Cycle

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, poorconnection, ending, corrosion, contamination, deterioration, or damage. Repair or replace asnecessary and go to "Verification of Vehicle Repair" procedure.

Terminal And Connector Inspection

1.	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.

2.	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 Inspection

Check Voltage

(1)	Ignition "OFF"

(2)	Disconnect PCM connector

(3)	Ignition "ON" & Engine "OFF"

(4)

Measure voltage between memory power terminal of PCM harness connector and chassis ground.

Specification : B+

(5)

Is the measured voltage within specifications?

	▶ Substitute 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.
	▶ Check for open or short to ground in harness. ▶ Check whether fuse is installed or blown off. ▶ Repair or replace as necessary and then, go to "Verification of Vehicle Repair"procedure.

There is a memory reset function on scantool that can erase optional parts automatically detected and memorized by PCM. After testing PCM on the vehicle, use this function before reusing the PCM

Verification Of Vehicle Repair

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

1.	Connect scantool and select "DTC" button.

2.	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

3.	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.