Code No. P1608: Battery Current Sensor System
OPERATION
- A power voltage of 5 V is applied to the battery current sensor connector terminal from the engine-ECU connector terminal ECB5 and is earthed to the engine-ECU connector terminal AFSE&ECBE from the battery current sensor connector terminal.
- The battery current sensor connector terminal outputs a sensor signal, which is input into the engine-ECU connector terminal ECB.
FUNCTION
- The battery current sensor detects a battery current and inputs a signal into the engine-ECU.
- In response to the signal, the engine-ECU controls charging and discharging.
TROUBLE JUDGEMENT
Check Condition
- Battery positive voltage is 8 - 16 V.
- 2 seconds later after the ignition switch has been in "ON" position or the engine has started up.
Judgement Criterion
- The battery current sensor output voltage is less than 0.2 V.
or
- The battery current sensor output voltage is more than 4.7 V.
FAIL-SAFE AND BACKUP FUNCTION
PROBABLE CAUSES
- Failed battery current sensor
- Open/short circuit or harness damage in battery current sensor circuit or loose connector contact
- Failed engine-ECU
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STEP 1. Check battery current sensor itself.
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- Check battery current sensor itself (Refer to GROUP 54A - Battery - On-vehicle Service - Battery Current Sensor Check <2200>
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Q.
Is the check result normal?
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 Go to Step 2.
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 Replace the battery current sensor.
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STEP 2. Voltage measurement at battery current sensor connector (ECB5 line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(3)Check the voltage between the battery current sensor connector (ECB5 line) and body earth.
OK: 4.9 - 5.1 V
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Q.
Is the check result normal?
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Go to Step 4.
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Go to Step 3.
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STEP 3. Check of open circuit and short to earth in ECB5 line between engine-ECU connector and battery current sensor connector.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the connector(s) or wiring harness.
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STEP 4. Resistance measurement at battery current sensor connector (AFSE&ECBE line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the battery current sensor connector (AFSE&ECBE line) and body earth.
OK: Continuity (2 Ω or less)
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Q.
Is the check result normal?
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Go to Step 6.
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Go to Step 5.
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STEP 5. Check of open circuit and damage in AFSE&ECBE line between battery current sensor connector and suction control valve connector.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the connector(s) or wiring harness.
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STEP 6. Check of damage in ECB5 line between engine-ECU connector and battery current sensor connector.
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Q.
Is the check result normal?
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Go to Step 7.
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Repair the connector(s) or wiring harness.
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STEP 7. Check of open circuit, short to earth, and damage in ECB line between battery current sensor connector and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 8.
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Repair the connector(s) or wiring harness.
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STEP 8. M.U.T.-III diagnosis code
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- Reconfirmation of diagnosis code.
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Q.
Is the diagnosis code set?
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Replace the engine-ECU.
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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