P1552

P1551, P1552 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 CHG-6, "System
Description".
<-- Vehicle front

CAUTION:
Do not 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.




On Board Diagnosis Logic
The MIL will not light up for these self-diagnoses.

NOTE:
If DTC P1551 or P1552 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to P0643.

On Board Diagnosis Logic:

DTC Confirmation Procedure
If DTC Confirmation Procedure has been previously conducted, always perform the following before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V with ignition switch ON
1. Turn ignition switch ON.
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to P1551.




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.
<-- Vehicle front





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

Voltage: Approximately 5V

OK or NG
OK - GO TO 4.
NG - GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
- Harness connectors E5, F14
- 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 E5, F14
- 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 E2, F32
- 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 P1551.
OK or NG
OK - GO TO 9.
NG - Replace battery negative cable assembly.
9.CHECK INTERMITTENT INCIDENT
Refer to How to Check Terminal and Intermittent Incident.
>> INSPECTION END




Component Inspection

BATTERY CURRENT SENSOR
1. Reconnect harness connectors disconnected.





2. Disconnect battery negative cable (1).
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 2.5V

6. If NG, replace battery negative cable assembly.