Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. P0605 OBD-II Trouble Code: Internal Control Module ROM Error

P0605 OBD-II Trouble Code: Internal Control Module ROM Error

P0605 code definition

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

What the P0605 code means

The Engine Control Module (ECM) is responsible for many major vehicle functions such as ignition timing, anti lock-braking, fuel injection, traction control, electronic power steering (most new makes of vehicles have this) cooling fan operation and emission controls. It is also responsible for smaller tasks such as window operation, radio, and even the horn.

ROM stands for Read Only Memory. The memory consists of parameters the Engine Control Module stores inside of a processor that can not be erased. The Parameters include tests and numeric ranges that the ECM permanently stores for use every time the vehicle is operated in any way. The parameters are several guidelines of how the processor should interpret the codes, and values being sent to it from things including, but not limited to oxygen sensors, mass air flow (MAF) sensors, interior buttons, crank position sensors, and other forms of engine management.

If the information sent to the Engine Control Module does not match the values that are stored in the processor by the manufacturer, a Check Engine Light will occur. There is a possibility that the memory stored in the ECM has been lost or disrupted if a code P0605 occurs.

What causes the P0605 code?

  • Defective or interrupted Engine Control Module ground or power supply
  • Broken Solder point(s) on the circuit board(s) of the ECM from heat or vibrations
  • Loss of memory in the ECM
  • ECM needs to be updated or re-flashed

What are the symptoms of the P0605 code?

  • A Check Engine Light being set
  • Engine misfire
  • Possibly a no start condition
  • Engine stall or hesitation

How does a mechanic diagnose the P0605 code?

  • Checks the related Technical Service Bulletins (TSB’s) and recalls to determine if the Engine Control Module may need an update, flash, or reprogramming

  • Inspects the wires connecting to the ECM

  • Inspects the electrical terminals connecting to the ECM

  • Tests the ECM for proper ground points and power supplies

Common mistakes when diagnosing the P0605 code?

  • Failing to research whether there is a TSB or recall related to updating, flashing, or reprogramming the Engine Control Module

  • Deeming the ECM as bad without verifying that the power supply and grounds to the ECM are good

How serious is the P0605 code?

It is fairly serious and should be addressed immediately. Think of it like this: The Engine Control Module is essentially the mind of a vehicle. Much the same to the operations of a human brain. They both run off of electricity. Similar to how a brain will control functions of a body such as heart rate, breathing rate and motor skills.

The vehicle itself can be compared to the body of oneself. If a brain undergoes any error, there may be a loss in bodily functions. If the ECM has an error, there may be a loss in sufficient control of vehicle functions: the heart rate, (which is, indirectly, ignition timing,) breathing rate, (which is, indirectly, the amount of air a car will suck in through its intake in accordance to the driver demands,) and motor skills. In this case, motor skills can be used as a literal term because a motor is an engine, and the skills are what the ECM uses to control the motor.

What repairs can fix the P0605 code?

  • Repairing a faulty ground or power supply such as corroded components and damaged wiring

  • An Engine Control Module update, reprogramming or reflash (if applicable)

  • Replacing the ECM

Additional comments for consideration regarding the P0605 code

A new Engine Control Module must be programmed to the vehicle. Oftentimes, a reprogramming can only be done with specialty equipment that is commonly only available to the dealership, though some sources other than the dealership may have that equipment. I suggest that you ask the potential installer of the ECM if they have the necessary specialty equipment in order to complete the job.

Need help with a P0605 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
Veteran and Military Driver Laws and Benefits in New Mexico
The state of New Mexico offers a number of benefits and perks for those Americans who have either served in an Armed Forces branch...


Related questions

Q: P0755 & P0700 error codes

The problem with buying used tires and not having them balanced is the potential problems they can cause. Most transmissions - or more specifically, the Powertrain Control Module (PCM) which controls the transmission and drive line - contain incredibly...

Q: Shutoff during start, Check Engine Light on, power loss - 1990 Mazda B2200

First thing is to check to see what problem codes are setting off the Check Engine Light. The compression numbers you mention are also pretty low, indicating worn piston rings, or burned valves. If you would like, a certified technician...

Q: Whats wrong , engine codes p0605,p0842,p0642, and p0401 thrown twice , light front end damage wothout airbag deployment

Hello, thank you for writing in. If the vehicle was in a wreck, the issues are likely independent from each other. One issue seems to be a powertrain control module electrical malfunction. This could be an issue with an input...