Code PO601, will not stay running?

Hi,

The code means that the PCM's Memory checksum test is failing. This is a self-test that is performed periodically throughout use. This is an important component because the PCM depends on it for storage of the operating system software. Without that information, what you are experiencing can be expected.

Now, the cause can be a few things. First, the voltage to the PCM can be low or the PCM's ground may be weak. If these two things are good, the PCM likely needs to be replaced.

Pic 1 below shows the power supply to the PCM C1 Pin 20). The next two pics are the ground location. If you look at pic 2, you'll see there are several important parts that ground to the same place, so we need to make sure that the connection is clean, tight, and free of damage and corrosion.

Pic 3 shows the ground location. That is where I would start. Check that first because it is a more likely cause than power. If the ground is good, then you need to check for 12v to the PCM. If that is good, the PCM is my first suspect.

Let me know if you have questions and what you find.

Take care,

Joe

See pics below.