P0605

Internal Control Module ROM Error (Module Identification Defined by SAE J1979)

What this code means

Internal Control Module ROM Error (Module Identification Defined by SAE J1979). Faults internal to the engine control unit or to its output circuits. Before suspecting the unit itself, which seldom fails, check grounds, connectors and battery voltage.

How to read this code

• PPowertrain
• 0standardised code
• 6Control unit and output circuits
• 05P0605

The letter P names the system: Powertrain. The digit 0 that follows marks a standardised code, shared by all manufacturers code. The next digit, 6, locates the fault: control unit and output circuits.

What to do

Have it checked this week. The car remains usable, but the fault will not clear itself and will fail the roadworthiness test.

Nearby codes

• P0600Serial Communication Link Malfunction
• P0601Internal Control Module Memory Check Sum Error
• P0602Control Module Programming Error
• P0603Internal Control Module Keep Alive Memory (KAM) Error
• P0604Internal Control Module RAM Error
• P0606PCM Processor Fault
• P0608Control Module VSS Output A Malfunction
• P0609Control Module VSS Output B Malfunction