P0603 Nissan Code - Engine Control Module Power Supply Circuit
Quick Answer
Battery voltage is supplied to the Engine Control Module (ECM) even when the ignition switch is turned OFF for the ECM memory function of the DTC memory, the air-fuel ratio feedback compensation value memory, the idle air volume learning value memory, etc. Common causes include Loose or poor battery terminal connection, Low battery charge, Faulty Engine Control Module (ECM). Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0603 Nissan indicates Engine Control Module Power Supply Circuit.
- Common causes
- Common causes include Loose or poor battery terminal connection, Low battery charge, Faulty Engine Control Module (ECM).
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0603 Nissan Description
What are the Possible Causes of the DTC P0603 Nissan?
- Loose or poor battery terminal connection
- Low battery charge
- Faulty Engine Control Module (ECM)
- ECM power supply circuit is open or shorted
- ECM Outdated Program
How to Fix the DTC P0603 Nissan?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0603 Nissan code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0603 Nissan code?
Need more information on how to fix the P0603 Nissan code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P0603 Nissan code diagnosed by a professional: Find a repair shop in your area
Information for Specific Nissan Models
- P0603 2006 Nissan Altima Sedan — Engine Control Module Power Supply Circuit
- P0603 2008 Nissan Altima Sedan — Engine Control Module Power Supply Circuit
- P0603 2009 Nissan Altima Sedan — Engine Control Module Power Supply Circuit
- P0603 2010 Nissan Altima Sedan — Engine Control Module Power Supply Circuit
- P0603 2011 Nissan Altima Sedan — Engine Control Module Power Supply Circuit
- P0603 2012 Nissan Altima Sedan — Engine Control Module Power Supply Circuit
- P0603 2006 Nissan Maxima — Engine Control Module Power Supply Circuit
- P0603 2007 Nissan Maxima — Engine Control Module Power Supply Circuit
- P0603 2008 Nissan Maxima — Engine Control Module Power Supply Circuit
- P0603 2005 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2006 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2007 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2008 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2009 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2010 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2011 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2012 Nissan Pathfinder — Engine Control Module Power Supply Circuit
- P0603 2008 Nissan Rogue — Engine Control Module Power Supply Circuit
- P0603 2009 Nissan Rogue — Engine Control Module Power Supply Circuit
- P0603 2010 Nissan Rogue — Engine Control Module Power Supply Circuit
- P0603 2011 Nissan Rogue — Engine Control Module Power Supply Circuit
- P0603 2012 Nissan Rogue — Engine Control Module Power Supply Circuit
- P0603 2013 Nissan Rogue — Engine Control Module Power Supply Circuit
- P0603 2007 Nissan Sentra — Engine Control Module Power Supply Circuit
- P0603 2008 Nissan Sentra — Engine Control Module Power Supply Circuit
- P0603 2009 Nissan Sentra — Engine Control Module Power Supply Circuit
- P0603 2010 Nissan Sentra — Engine Control Module Power Supply Circuit
- P0603 2011 Nissan Sentra — Engine Control Module Power Supply Circuit
- P0603 2012 Nissan Sentra — Engine Control Module Power Supply Circuit
Frequently Asked Questions about P0603 Nissan Code
1. What does the OBDII code P0603 Nissan indicate?
The P0603 code on a Nissan indicates an issue with the Engine Control Module (ECM) power supply circuit, suggesting there might be a problem with the internal memory (KAM) which can affect the settings stored in the ECM.
2. What are common symptoms of the P0603 code in a Nissan?
Symptoms can include the Check Engine Light coming on, erratic engine behavior, poor fuel economy, and potentially the engine failing to start or stalling unexpectedly.
3. What can cause the P0603 code to appear in my Nissan?
Causes of the P0603 code include a faulty ECM, poor electrical connections to the ECM, low battery voltage, or issues with the power supply circuit such as corroded or loose wires.
4. How do I fix the P0603 code on my Nissan?
Repairing the P0603 code involves checking and correcting the battery voltage if it's low, ensuring that all ECM connections are secure and free from corrosion, or replacing the ECM if it is found to be defective.
5. Is it safe to drive my Nissan with the P0603 code?
While you may be able to drive with this code active, it is not recommended as it can lead to more serious issues like engine stalling, which can compromise vehicle safety.
6. How urgent is it to address the P0603 code in a Nissan?
It is fairly urgent to address the P0603 code because prolonged issues with the ECM power supply can lead to decreased performance and potential engine damage.
7. What tools are needed to diagnose the P0603 code on a Nissan?
Diagnosing the P0603 code typically requires an OBD-II scanner, a digital multimeter, and sometimes a scope, to check the integrity and voltage of wiring and connections in the ECM power supply circuit.
8. Can a weak car battery cause the P0603 code to appear?
Yes, a weak or failing battery can cause insufficient power supply to the ECM, which might trigger the P0603 code.
9. What is the cost implication of fixing the P0603 code in a Nissan?
The cost can vary widely depending on the underlying issue. Battery replacement, if needed, can be relatively inexpensive, whereas ECM replacement can be costly, potentially running into several hundred dollars.
10. How can I prevent the P0603 code from recurring in my Nissan?
Regular maintenance of the vehicle’s electrical system, including checking the battery and ensuring all ECM connections are clean and secure, can help prevent recurrence of the P0603 code.
Discuss the causes and fixes for P0603 Nissan OBDII Code
-
Hi this code came about since I have been having problems with my battery.I bought a new battery 4 days ago. The manager put the new battery in however I was still having to go under the hood and tap positive post to crank my vehicle. Today the check engine light came on and when I had it checked this is the code it gave, so my question is should I replace the post now?
-
You mean replace the battery terminal? it depends how bad it is. You could just try to tighten the terminal.
-
I check my frontier Nissan 2008 my scanner l have the light common service engine soon
The scanner give me code p 0603 l don’t know what to do -
Start by charging the vehicles battery and clean terminal, once the battery is charged and the terminals are clean and secure, erase code. If the code comes back ON you may have to reprogram or replaced Engine Control Module (ECM) at the dealer.
-
this code came up on our 2006 nissan titan. when i went to get in my truck all the dash lights were on but no key was in the ignition and it would not start. I switched a few relays and it started but It will not turn off until i take out the relays and unhook the battery cable.
-
Do you know what relays did you swap? swapping relay is not a good idea, not all the relays are the same.
There is a factory service bulletin that recommends checking the battery charge first and clearing the codes.
I recommend swapping back the relays to the original place and then check the battery charge. Make sure the battery terminals are clean and tight. -
I have a battery disconnect to shut my battery off because It will set for a week before I run it again, would this cause this code PO603 to come on?
-
Yes, a battery disconnect can cause P0603 on a Nissan. That code means the ECM lost its keep-alive memory power, and disconnecting the battery cuts that memory feed completely.
If the code only appears after you use the battery disconnect and the vehicle otherwise runs normally, that may be the reason. I would still make sure the battery terminals and ECM power supply connections are clean and tight. If P0603 starts returning even when the battery has not been disconnected, then check for low battery voltage, a poor power/ground connection, or an ECM power supply circuit problem.
-
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
