STEP 1. Check battery itself
STEP 2. Check battery test
STEP 3. Check battery current sensor itself
STEP 4. Check harness connector A-41 at battery current sensor and harness connector B-27 at ECM for damage.
STEP 5. Check for harness damage between battery current sensor connector A-41 (terminal No. 1) and ECM connector B-27 (terminal No. 99).
STEP 6. Check for harness damage between battery current sensor connector A-41 (terminal No. 3) and ECM connector B-27 (terminal No. 101).
STEP 7. Check for harness damage between battery current sensor connector A-41 (terminal No. 4) and ECM connector B-27 (terminal No. 100).
STEP 8. Using scan tool MB991958, read the diagnostic trouble code (DTC).
(1) Connect scan tool MB991958 to the data link connector.
(2) Start the engine and run at idle.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P1609 set?
Replace the ECM (Refer to, Removal and Installation ). Then go to Step 9. It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
STEP 9. Using scan tool MB991958, read the diagnostic trouble code (DTC).
(1) Connect scan tool MB991958 to the data link connector.
(2) Start the engine and run at idle.
(3) After the DTC has been deleted, read the DTC again.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is DTC P1609 set?
Retry the troubleshooting. The inspection is complete.