Error Code P0601 is defined as Internal Control Module Memory Check Sum Error. This refers to a fault in the internal control memory of the PCM.

There are many reports of PCM failures on Chrysler and Dodge vehicles, although this code is very possible to appear on any vehicle makes. For Chrysler and Dodge, this code means that a serial communication failed inside the PCM for at least six times.

This code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, or vehicles made since 1996 up to present. Specifications on the definition, troubleshooting and repairs of course, vary from one make and/or model to another.


Error Code P0601 is set when there’s a memory check sum error detected in the internal control module. This error is within the PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) and is found when the PCM conducts a self-check. This will cause the Check Engine light to light up and put the vehicle on failsafe mode to minimize potential damage to the vehicle. Failsafe mode will only be disabled after the problem is fixed.

Other related internal control module error codes include:

Common Symptoms

Error Code P0601 may be tricky to identify, as it may not show any discernible symptoms for the driver in some cases, except of course, from the activation of the Check Engine light on the dashboard. Usually, the engine runs fine and the gauges work.

For some cases with symptoms however, the symptoms are usually:

  • ABS and traction control lights are on
  • Engine may not start
  • Vehicle may struggle running or may die while running
  • Vehicle may not shift properly

Possible Causes

Error Code P0601 means the PCM has gone bad, which can be caused by a short circuit within the PCM itself, or if wires and connectors from the PCM is disconnected while the battery is still connected. The most common cause of this error code is a faulty or damaged PCM and low voltage to the PCM.

How to Check

Technicians start their diagnosis for this code by hooking up the vehicle’s DLC port to a scan tool and checking for all codes present, as well as the preset history and pending code.

Then, the technician will take note of the freeze frame data for every code. He will use this information to discern the condition, such as engine load, RPM, and coolant temperature the vehicle has when the code was set.

Next, the codes will be cleared and the vehicle will be taken for a test drive to confirm if the same issue reappears and if the code sets again.

Next, technicians conduct a visual inspection and actively look for signs of damages and circuits and wirings of the involved components.

Then, they will use a multimeter to check whether the PCM receives proper voltage supply.

Lastly, they will test the PCM. Each vehicle usually has its own PCM-testing procedures.

How to Fix

The most common fix for this error code is replacing or reprograming the PCM. In some few cases, dealers may reflash the PCM and get it working. But most often than not, the code means the PCM must be replaced and reprogrammed. This is why it’s important that you take your vehicle to its dealership for this problem.

The good news is that, this problem may be covered by emission warranty. Thus, even if you’re out of powertrain warranty and bumper-to-bumper warranty, you can still get good help for this code.

In some cases, people report the code returns again and again even after replacing the PCM. This is because though most shops can replace the PCM, not all shots can program it. Obviously, you need to find a shop that can reprogram your PCM.

The seriousness and severity of Error Code P0601 mostly depends on its symptoms. Moreover, the vehicle must not be driven if it shows extreme drivability faults or struggles to in running.