2001 Dodge Grand Caravan Getting Codes p0600 serial communication and SPI codes. Replaced the PCM/ECM computer and still getting same codes. Could this be a harness or connector issue?

Question edited for clarity. Please always quote DTC Codes in full. '129' is not the same as 'P0129'. Single numerical codes are usually computer communication codes.
Question moved to model category.

When you did all this work, did you disconnect the battery?
Did you reset the security system and engine immobilizer?
Is the anti-theft light flashing, flashing fast or on steady?

Help and videos

https://www.google.com/search?q=2006+Dodge+Grand+Caravan+3.3+turns+over+but+won%27t+start

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The reason of Dodge Grand Caravan P0600 OBD-II Engine Trouble Code is P0600 Loss of Serial Communication Link. To clear the code take it to a auto zone and see if they will flash it what that does is remove the code. But it will come back on as the problem needs to be fixed.

Sounds like the link between your dashboard and the main ECM is starting to go bad. Without this link your dashboard will not work. P0600 ****** Communication Link Malfunction Source: http://forums.focaljet.com/mk-i-tech/522844-every-trouble-code-defined.html

Loss of serial communication link
Faulty ECM computer
ECM connection bad
Low battery voltage

Check battery voltage and disconnect and clean connection of computer

When "check engine" litgh tun on, the PCM (computer) is warning that some fault code is stored there. Autozone could scanned your PCM and show exactly what fault codes is there; if your O2 sensors was replaced, I assuming that they can see this codes... so, they reset and delete all codes stored there? Scanned the PCM after this change?

Keep us updated-

CODE PO600 SERIAL COMMUNICATION LINK MALFUNCTION. POSSIBLE CAUSES PCM OR SPI FAILURE.

Chrysler EVAP P0442 P0445 Smoke Diagnostics
P1698 Dodge PCM Fault No CCD Message From TCM
Do you know what a serial data communication network is ?
CCD SCI DATA LINES TECH TIP

Sorry dude but you don't have a prayer of a chance to fix this ! You know anything about automotive electronics , electrical systems ? Have a factory or professional scan tool . Going to advance auto won't cut it .

P0601 - Internal Control Module Memory Check Sum Error

Basically that means that there is an interal fault in the Powertrain Control Module (PCM). There have been many reported PCM failures on Chrysler/Dodge products although it is possible for this to happen on any vehicle. In Dodge/Chrysler products, a P0601 trouble code means that a serial communication failed inside the computer at least 6 times.

Symptoms: Likely, no symptoms will be discernible to the driver, other than the illuminated Check Engine Light. Typically the engine runs fine, gauges work, etc.

Causes: A code P0601 in most cases means the PCM has gone bad. This is possibly due to a short-circuit inside the PCM. Or, if you disconnect the wires/connector from the PCM while the battery is still connected, that may also cause this code.

Possible Solutions: With a P0601 OBD-II trouble code, the most common fix is to replace and reprogram the PCM. In a few cases the dealer may be able to reflash the PCM and get it working. But more than likely the PCM will need to be replaced and reprogrammed (we recommend you take it to a dealership for this). The good news is it *may* be covered under your emmissions warranty. So even if you're out of bumper-to-bumper warranty or powertrain warranty, check your warranty guide or dealer to see if this is covered.

Other people have reported that they cleared the code only for it to return again and again. Keep in mind that most shops can replace the PCM but not all can program it.

Other PCM / ECM Codes: P0602, P0603, P0604, P0605, P0606, P0607, P0608, P0609, P0610.

Hope this help to solve it (remember rated this).

P0600-P0699 Are all Computer Output Circuit

660 is Intake Manifold Ait Control Solenoid Circuit Bank 1

662 is Intake Manifold Air Control Solenoid Circuit High Bank1

664 is Intake Manifold Air Control Solenoid Circuit Low Bank 2

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