Chrysler Repair: 2001 Chrysler T/C OBD2 DTC P0601, haynes manual, co processors

Question
Hello Roland,

I understand because of the year of my vehicle this may be outside your knowledge, but it's most certainly outside mine! So I thought it worth a try!

I have a 2001 Town and Country that the MIL recently came on. I performed the "key" method of accessing the DTC and received a P1684 and P0601. So far I've found the P1684 as a battery disconnect in the last 50 starts...so no worries. The P0601 however, calls out an "Internal Control Module Memory Checksum Error". Further research seems to point to "ECU's" and "PCM's" and frankly I'm a little buried in the terminology. The fault is repeatable, I borrowed a scan tool and erased the code, and it immediately reappears upon start up. My question: Specifically which module is this calling out or what diagnostics can I perform to narrow this down a little. Thanks for your reply!

Regards,

Paul  

Answer
Hi Paul,
I was interested to know that the key would give you a diagnostic readout. Out of curiosity, was it an "on-off-on-off-on" and where did it readout? I had thought that the key readout only applied to some very early OBD II systems.
On the P0601, the two lists I have just show the P0600 but they also refer to the powertain control module (engine controller): "No communication between the co-processors in the control module" - spi communications failire in the pcm. The trouble shooting manual doesn't offer any further testing which implies to me that the engine controller sees itself as non-functional in that respect. I see that P0600 code in the Haynes manual too, as you described it, and everything seems to point to an internal problem with the engine controller. So you may need to try and find a replacement controller at a wrecking yard is all I can suggest. Let me know about the Key method if you would be so kind.
Roland