Overheating, cooling fan will not turn on and code P0601

ELIZABETH DENISE ANDREWS

MEMBER
2002 CHRYSLER PT CRUISER
2.4L
4 CYL
2WD
AUTOMATIC
157,000 MILES

My car idles up and down, and hard shifts. I had a blow out and after I changed the tire my temperature gauge wasn't working anymore. Now is running hot and the fan is not coming on. The diagnostics says p0601. Something about the computer check sum. Anyways, I am trying to figure out how I can straight wire the fan because I know it is working, I had that checked. I just need to try to keep it from overheating until I can at least afford a computer, I found a used one but I'm not sure what I need to do to make sure it'll work on my car. How I can program it or if maybe I could reprogram mine? I am a pregnant female and know nothing about cars it's my only way of going. Please help.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

The cooling fan issue is likely related to the powertrain control module failure. I don't see a need to hotwire it at this point.

I'm not sure why the problem started with a blowout, but something happened. Here is what the code indicates (right from my manual):

2002 Chrysler Truck PT Cruiser L4-2.4L VIN B
P0601
Vehicle ALL Diagnostic Trouble Codes ( DTC ) Testing and Inspection P Code Charts P0601
P0601
Test 1

See pic 1

SYMPTOM
P0601-PCM INTERNAL CONTROLLER FAILURE

TEST NOTE
This symptom is diagnosed using the test P0600-PCM FAILURE SPI COMMUNICATIONS.

WHEN MONITORED
Ignition key ON.

SET CONDITION
Internal checksum for software failed, does not match calculated value.

POSSIBLE CAUSES
- PCM Internal Or SPI

_______________________________

Now, the directions indicate either a failed PCM or an issue with the SPI (serial peripheral interface). In understandable terms, there could be a break down in communication in the controller area network (CAN). The CAN is a means of communication between all of the modules/computers via a few wires.

When the tire blew out, was there any damage done to the vehicle? If not, the next thing I would try is to scan the can-bus system to see if there is an indication of possible can issues.

Here is a video showing how that is done:

https://youtu.be/InIlnsjOVFA

If you still find a P0601 is the only code, there is a good chance the PCM has an internal fault and needs replaced.

Let me know if that helps or if you have other questions.

Take care,
Joe

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