P1554

DTC P1554 BATTERY CURRENT SENSOR





Component Description





The power generation voltage variable control enables fuel consumption to be decreased by reducing the engine load which is caused by the power generation of the generator. The battery current sensor (1) is installed to the battery cable at the negative terminal. The sensor measures the charging/discharging current of the battery. Based on the sensor signal, ECM judges whether or not the power generation voltage variable control is performed. When performing the power generation voltage variable control, ECM calculates the target power generation voltage based on the sensor signal. And ECM sends the calculated value as the power generation command value to IPDM E/R. For the details of the power generation voltage variable control, refer to SC section.
- : Vehicle front

CAUTION:
Never connect the electrical component or the ground wire directly to the battery terminal. The connection causes the malfunction of the power generation voltage variable control, and then the battery discharge may occur.




CONSULT-III Reference Value in Data Monitor Mode
Specification data are reference values.









On Board Diagnosis Logic
The MIL will not illuminate for this diagnosis.

NOTE:
If DTC P1554 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to P0643.

On Board Diagnosis Logic:

Overall Function Check
Use this procedure to check the overall function of the battery current sensor circuit. During this check, a 1st trip DTC might not be confirmed.
TESTING CONDITION:
- Before performing the following procedure, confirm that battery voltage is more than 12.8 V at idle.
- Before performing the following procedure, confirm that all load switches and A/C switch are turned
OFF.

WITH CONSULT-III
1. Start engine and let it idle.
2. Select "BAT CUR SEN" in "DATA MONITOR" mode with CONSULT-III.
3. Check "BAT CUR SEN" indication for 10 seconds.
"BAT CUR SEN" indication should be above 2,300 mV at least once.
4. If NG, go to P1554.

WITH GST
1. Start engine and let it idle.





2. Check voltage between ECM terminal 71 (battery current sensor signal) and ground for 10 seconds.
The voltage should be above 2.3 V at least once.
3. If NG, go to P1554.




Wiring Diagram
Specification data are reference values and are measured between each terminal and ground.

CAUTION:
Never use ECM ground terminals when measuring input/output voltage. Doing so may result in damage to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.









Diagnosis Procedure
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to Power Supply and Ground Circuit.





OK or NG
OK - GO TO 2.
NG - Repair or replace ground connections.
2.CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT





1. Disconnect battery current sensor (1) harness connector.
2. Turn ignition switch ON.





3. Check voltage between battery current sensor terminal 1 and ground with CONSULT-III or tester.

Voltage: Approximately 5 V

OK or NG
OK - GO TO 4.
NG - GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E11, F2
- Harness for open or short between battery current sensor and ECM
Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK BATTERY CURRENT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between battery current sensor terminal 2 and ECM terminal 67. Refer to Wiring Diagram.

Continuity should exist.

4. Also check harness for short to ground and short to power.
OK or NG
OK - GO TO 6.
NG - GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E73, F68
- Harness for open or short between battery current sensor and ECM
Repair open circuit or short to ground or short to power in harness or connectors.
6.CHECK BATTERY CURRENT SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between battery current sensor terminal 3 and ECM terminal 71. Refer to Wiring Diagram.

Continuity should exist.

2. Also check harness for short to ground and short to power.
OK or NG
OK - GO TO 8.
NG - GO TO 7.
7.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E73, F68
- Harness for open or short between battery current sensor and ECM
Repair open circuit or short to ground or short to power in harness or connectors.
8.CHECK BATTERY CURRENT SENSOR
Refer to P1554.
OK or NG
OK - GO TO 9.
NG - Replace battery negative cable assembly.
9.CHECK INTERMITTENT INCIDENT
Refer to Diagnosis Procedure.
INSPECTION END




Component Inspection

BATTERY CURRENT SENSOR
1. Reconnect harness connectors disconnected.





2. Disconnect battery negative cable (1).
- : To body ground
3. Install jumper cable A between battery negative terminal and body ground.
4. Turn ignition switch ON.





5. Check voltage between ECM terminal 71 (battery current sensor signal) and ground.

Voltage: Approximately 2.5 V

6. If NG, replace battery negative cable assembly.