Internal Control Module Malfunction
2008-2008 Volvo S80 2.9L I6
The 2008 Volvo S80 is equipped with a 2.9L inline-6 engine. Below you'll find detailed p1603 diagnostic code information including labor time estimates, cost ranges, and technician notes specific to this engine configuration.
Description
The ECM detected an internal hardware or software malfunction. The ECM self-diagnostic routines have identified a failure in one of its internal circuits or memory areas.
Symptoms
- Check Engine Light
- Various driveability issues
- Other fault codes may appear
- Intermittent problems
Common Causes
- ECM internal circuit failure
- ECM memory corruption
- Voltage spike or brown-out damage
- ECM software error
- Poor ECM ground connection
Diagnostic Steps
- Check all ECM power and ground connections
- Clear codes and verify if fault returns
- Update ECM software to latest version
- Test ECM supply voltage stability
- Replace ECM if internal fault confirmed
Repair Notes
Update ECM software; replace ECM if internal malfunction persists after reprogramming.
Related Codes
Other Powertrain Codes
- P0001Fuel Volume Regulator Control Circuit/Open
- P0002Fuel Volume Regulator Control Circuit Range/Performance
- P0003Fuel Volume Regulator Control Circuit Low
- P0004Fuel Volume Regulator Control Circuit High
- P0010Intake Camshaft Position Actuator Circuit/Open Bank 1
- P0011Intake Camshaft Position Timing Over-Advanced Bank 1
- P0012Intake Camshaft Position Timing Over-Retarded Bank 1
- P0013Exhaust Camshaft Position Actuator Circuit/Open Bank 1
- P0014Exhaust Camshaft Position Timing Over-Advanced Bank 1
- P0015Exhaust Camshaft Position Timing Over-Retarded Bank 1
P1603 on Other Vehicles
Common Questions
What does code P1603 mean on a 2008-2008 Volvo S80?
P1603 stands for "Internal Control Module Malfunction". The ECM detected an internal hardware or software malfunction. The ECM self-diagnostic routines have identified a failure in one of its internal circuits or memory areas.
What are the symptoms of P1603 on a Volvo S80?
Common symptoms of P1603 include: Check Engine Light, Various driveability issues, Other fault codes may appear, Intermittent problems.
What causes P1603 on a 2008-2008 Volvo S80?
Common causes of P1603 include: ECM internal circuit failure, ECM memory corruption, Voltage spike or brown-out damage, ECM software error, Poor ECM ground connection.
Last updated: March 2026