P1603 Mitsubishi Code - Battery Backup Line Malfunction
Quick Answer
The Powertrain Control Module (PCM) checks the open circuit of battery backup line. Common causes include Faulty Powertrain Control Module (PCM), PCM harness is open or shorted, PCM circuit poor electrical connection. 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
- P1603 Mitsubishi indicates Battery Backup Line Malfunction.
- Common causes
- Common causes include Faulty Powertrain Control Module (PCM), PCM harness is open or shorted, PCM circuit poor electrical connection.
- 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 P1603 Mitsubishi Description
NOTE: When the system detects an open circuit in the battery backup line, it makes 1 failure judgment of other diagnostic trouble codes (DTCs).
What are the Possible Causes of the DTC P1603 Mitsubishi?
- Faulty Powertrain Control Module (PCM)
- PCM harness is open or shorted
- PCM circuit poor electrical connection
How to Fix the DTC P1603 Mitsubishi?
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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1603 Mitsubishi 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 P1603 Mitsubishi code?
Need more information on how to fix the P1603 Mitsubishi code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P1603 Mitsubishi code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P1603 Mitsubishi Code
1. What does the OBDII code P1603 mean for a Mitsubishi vehicle?
P1603 indicates a "Battery Backup Line Malfunction," meaning there is an issue with the backup power supply to the engine control module (ECM).
2. What are the common symptoms of the P1603 code in a Mitsubishi?
Symptoms may include the check engine light turning on, difficulty starting the engine, loss of memory for certain settings, or erratic vehicle behavior.
3. What causes the P1603 code to appear in Mitsubishi vehicles?
Common causes include a weak or failing vehicle battery, damaged or corroded wiring to the ECM, a faulty backup power circuit, or a defective ECM.
4. Can a weak battery trigger the P1603 code?
Yes, a weak or failing battery can cause the backup power supply to the ECM to malfunction, resulting in the P1603 code.
5. How do I diagnose the P1603 code in my Mitsubishi?
Start by checking the vehicle's battery voltage, inspecting the wiring and connectors to the ECM, and testing the backup power circuit for continuity or shorts.
6. Can I drive my Mitsubishi with a P1603 code?
Driving with the P1603 code is not recommended, as it may lead to intermittent ECM functionality and unpredictable vehicle performance.
7. How do I fix the P1603 code in a Mitsubishi?
Possible fixes include replacing the vehicle battery, repairing or replacing damaged wiring, cleaning corroded connectors, or replacing the ECM if it is faulty.
8. Is the ECM always the cause of the P1603 code?
No, while a faulty ECM can trigger the code, it is more commonly caused by wiring issues or a weak battery. Always rule out simpler causes first.
9. Will disconnecting the battery clear the P1603 code?
Disconnecting the battery may temporarily clear the code, but if the underlying issue isn’t resolved, the code will likely return.
10. What tools are needed to troubleshoot the P1603 code?
You may need a multimeter to check voltage and continuity, an OBDII scanner to read and clear the code, and basic tools to inspect wiring and connectors.
Discuss the causes and fixes for P1603 Mitsubishi OBDII Code
-
My eclipse shuts off when i stop at a light but cranks right up again but i have to ride brake and gas so it wont cut off. It only happens when check engine light comes on i took it to advance and they got this code p1 603
-
What year is your Eclipse? Sounds like you may have a problem with the Powertrain Control Module (PCM).
-
-
ISH--SHOESSS..Rebuilt transmission-replaced steels and frictions, seals, o rings , serviced valve body while I had it apart, shift solenoids, new input/output speed sensors. Vehicle still slips in reverse, forward gear seems to catch fine but lags on shift, one rough shift triggers fail safe with code p1603. suggestions?
-
did you fix your problem my son has the exact car and has same code p1603
-
2001 eclipse 3.0 just lost all power, thought had died. Idle just fine touch gas and dies. Couldn't really figure out to well side of road and all . Now won't start at all. Code p 1603 is all ?
Any ideas? Would be appreciated
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
