Rick's Free Auto Repair Advice

P0603 Infiniti

Diagnose and fix P0603 Infiniti trouble code

Infiniti has issued a service bulletin #ITB16-008b to address a P0603 trouble code issue that may appear on all 2015 and later Infiniti vehicles. The P0603 (ECM BACK UP/CIRCUIT) trouble code will be stored and the check engine warning light will be on.

P0603 Infiniti diagnostic procedure

Infiniti recommends starting your diagnostic work with a battery voltage check. Make sure battery terminals are clean and tight. Battery voltage must be at least 11-volts with the IGN on but engine OFF. Next, erase the P0603 trouble code using a scan tool or code reader. Turn IGN to OFF, then back ON for at least one second. Then turn back to OFF for at least 10 seconds. Repeat the ON/OFF procedure 10 more times.

If battery voltage exceeds 11-volts and the code does not reappear, you’re done. If the code reappears, conduct a full battery load and conductance test. Replace the battery if it fails the test. If the battery tests good, check all electrical connections.

Infiniti advises that P0603 is often the result of low battery voltage, discharged battery or battery terminal disconnections.

©, 2019 Rick Muscoplat

Posted on by Rick Muscoplat


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