4.
Read "DTC Status" parameter.
Many control units have applied to vehicle as it becomes more electronical. These units control their own system based on information from diverse sensors. Therefore necessity of common use of diverse sensor information and importance of stable power supply are gathering strength. Battery sensor is mounted on battery (-) terminal. It transmits battery voltage, current, temperature information to ECM. ECM controls generating voltage by duty cycle based on these signals.
ECM sets this code when real output voltage is lower than target voltage.
Item | Detecting Condition | Possible cause |
DTC Strategy | ● Signal Monitoring | ● Open or short in harness ● Faulty battery sensor ● Poor connection |
Enable Conditions | ● IG "ON" ● No error related to LIN communication | |
Threshold value | ● Battery voltage at power supply terminal of ECM – voltage from battery sensor > 3V | |
Diagnosis Time | ● 60sec | |
MIL On Condition | ● NO MIL ON(DTC only) |
Connect scantool to Data Link Connector(DLC).
IG "ON".
Select "DTC" button, and then Press "DTC Status" to check DTC's information from the DTCs menu.
Read "DTC Status" parameter.
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 ECM’s connector or was repaired and ECM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and go to "Verification of vehicle Repair" procedure. |
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.
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. |
Engine starts.
Measure the voltage between on/start input terminal of ECM and B terminal of alternator.
Specification : below 1.0V
Is the measured voltage within specification ?
| ▶ Go to"Check Battery Voltage" as follows. |
| ▶ Repair open or short in harnesses and go to "Verification of Vehicle Repair". |
Engine starts.
Measure the voltage between + terminal of battery and B terminal of alternator.
Specification : below 1.0V
Is the measured voltage within specification ?
| ▶ Go to"Component Inspection" as follows. |
| ▶ Repair open or short in harnesses and go to "Verification of Vehicle Repair". |
Replace battery sensor.
IG "OFF"
Connect scantool to Data Link Connector(DLC).
Clear DTC and Test-drive under enable conditions above-mentioned.
Does the scantool show DTC "P2502"?
| ▶ Substitute with a known - good ECM and check for proper operation. If the problem is corrected, replace ECM and go to "Verification of Vehicle Repair" procedure. note There is a memory reset function on scantool that can erase optional parts automaticallydetected and memorized by ECM. Before or after testing ECM on the vehicle, use this function to reuse the ECM on the others. |
| ▶ Substitute with a known - good battery sensor and check for proper operation. If the problem is corrected, replace battery sensor and go to "Verification of Vehicle Repair" procedure. |
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. |
