P0605 Internal control module read-only memory (ROM) error

OBD-II - P0605 - Technical Description

P0605 - Error in read-only memory (ROM) of the internal control module.

Code P0605 is related to the vehicle's engine control module (also called the transmission control module in newer vehicles) . The ECM is like the brain of a car, without which none of the other engine functions will work properly! So, how can you diagnose such an error code and what can you do to fix it? Let's figure it out in this post.

What does trouble code P0605 mean?

This Diagnostic Trouble Code (DTC) is a generic transmission code, which means it applies to OBD-II equipped vehicles. Although general, specific repair steps may differ depending on the brand / model.

This DTC basically means that the PCM/ECM (Powertrain/Engine Control Module) has detected an internal ROM (Read Only Memory) control module fault in the PCM. The PCM is essentially the "electronic brain" of the vehicle that controls functions such as fuel injection, ignition, etc. When the self-test fails, the ROM is set to this DTC.

This code is a generic transmission code. It is considered universal as it applies to all makes and models of cars (1996 and newer), although the specific repair steps may differ slightly depending on the model. A quick search on the web reveals that this DTC is more common in Ford and Nissan vehicles.

Other error codes of the internal control module include:

• P0601 Internal control module memory checksum error
• P0602 Control module programming error
• P0603 Internal Control Module Keep Alive Memory (KAM) Error
• P0604 Internal control module random access memory (RAM) error

Photo of the PKM with the cover removed:

Symptoms

DTC P0605 symptoms include a MIL (Malfunction Indicator Lamp) illuminated, although there can be other symptoms, including but not limited to various warning lights on the dashboard, engine stalling, and no starting.

You may see the following symptoms, which may indicate a ROM error in the internal control module:

• The Check Engine light may be on.
• ABS/Traction Control light on
• Possible loss of fuel economy
• Misfire and engine stall
• The engine may not start at all.
• Transmission problems

Possible Causes of Code P0605

There can be several reasons for the appearance of such a diagnostic code:

• The power supply of the engine control unit may be faulty - the wrong voltage is being supplied.
• Bad ECM ROM
• Solder points may be broken in the ECM circuit.
• ECM may need to be updated
• There is an internal fault in the PCM / ECM.
• Using a aftermarket programmer may trigger this code

How serious is the P0605 code?

Imagine that in your body something happens to the brain - what do you think will be the result? Your normal bodily functions may go awry and your body may shut down! The same thing happens when there is a problem with the engine control module (ECM), especially code P0605. Therefore, it should be considered serious and corrected immediately.

In such a situation, the ECM cannot assess whether it is capable of driving the vehicle correctly. This may cause other functions such as ABS, transmission, ignition, fuel control, etc. to malfunction, which in turn may endanger the driver and passengers. The car may even start emitting harmful gases such as carbon monoxide and nitrogen oxides.

How can you diagnose a P0605 error code?

Have your vehicle checked by a trained technician or mechanic to successfully resolve the error. It usually does the following to diagnose:

• Check the wires connecting the ECM to other parts for problems.
• Inspect the ECM circuit board for solder point problems.
• Check for problems in the internal voltage and ground points.
• Review the relevant Technical Service Bulletins (TSB) to see if the ECM needs to be reprogrammed.

Possible solutions

In some cases, flashing the PCM with an updated software can correct this DTC. You will need access to production and model information such as Technical Service Bulletins (TSB).

If there are no PCM flash updates, the next step is to check the wiring. Visually inspect and verify proper voltage and grounding at the PCM and all connected circuits. If there are problems with them, repair and recheck.

If the wiring is ok, the next step is to replace the PCM, which is most likely a repair for this code. This is usually not a do-it-yourself task, although it may be in some cases. We strongly recommend that you go to a qualified repair shop / technician who can reprogram your new PCM. Installing a new PCM may involve using special tools to program the vehicle's VIN (Vehicle Identification Number) and / or anti-theft information (PATS, etc.).

As an alternative to replacing the PCM, some specialist retailers can actually repair the PCM. This could include removing the PCM, sending it to them for repair, and reinstalling it. This is not always an option for daily drivers.

NOTE. This repair may be covered by an emissions warranty, so be sure to check with your dealer as it may be covered beyond the warranty period between bumpers or transmission.

Other PCM DTCs: P0600, P0601, P0602, P0603, P0604, P0606, P0607, P0608, P0609, P0610.

Can you fix code P0605 yourself?

Unfortunately, you cannot fix the P0605 code yourself, as it requires a certain level of technical/electrical knowledge. The technician will be better equipped to troubleshoot problems in the ECM circuit, transmission module, software and more.

How much does it cost to fix code P0605?

It usually takes 0605 minutes to an hour to diagnose and fix a P30 code. Depending on store rates and labor rates, fixing this error code could cost you between $70 and $100 . However, in very rare cases, you may need a complete ECM replacement, which will cost you more than $800.

What is P0605 Engine Code [Quick Guide]

Need more help with your p0605 code?

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NOTE. This information is provided for informational purposes only. It is not intended to be used as a repair recommendation and we are not responsible for any action you take on any vehicle. All information on this site is protected by copyright.