[gee6]

Have you checked continuity on the harness wiring. The wires to the crank sensor, particularly, can degrade with age and heat. They become vulnerable when the sensors are changed. Just a thought.

 

[gee6]

Bad earths? Engine, ECU, etc, etc.

 

[gee6]

At last you may be getting somewhere. For my money (which isn't worth so much these days!) I would still plump for an electrical issue (Open earth?). This may be simply down to a bad harness connector, but they are really hard to track down. Until you can be assured you have good connections, please don't throw more parts at the vehicle .....

There are numerous posts (even on this forum) regarding the P codes you have. Especially P1631, which is an odd one. I presume you are in USA??? Then your 2004 should not have an immobiliser which is one problem area for that code. Therefore, something else would be causing a FAIL signal to the ECM (The fact codes are still there indicates the ECM is working) and it is retaining the FAIl signal. Start (fuel/ignition/injection) will remain deactivated until the fault is corrected. ie you will not get the signals you are expecting because of the FAULT, not because the control boxes are not working.

If you are searching on Google try explicitly mentioning Kia (eg "OBDII code P1631 - Kia Sorento" ) to narrow down the results to your vehicle type since each manfr will have there own take on the code. (It even varies between countries - even our old 3.5V6 models had immobilisers and diesels have entirely different systems.)

 

[gee6]

Immobilisers were not introduced until facelift models (mid 2006) in the USA (when they opened the Georgia plant) as far as I know. A Canadian model would probably have one fitted by that date, but the location you describe sounds wrong. Bottom of centre console (behind the drawer assembly) is location for Body Control Module, which is common to all models but may have more/less functions. The BCM can have an impact on non-start in a FAIL condition as with the ECM. The ECM might detect a FAIL directly, or might accept a FAIL condition from the BCM. (I am paraphrasing.)

Please note one possible cause for P1631 is no alternator output detected. I'm not sure that would directly affect starting but it could be the BCM/ECM is doing it's thing and inhibiting start to prevent damage.

 

[gee6]

It might just be down to a bad harness connector. Here we have had particular problems with a connector that sits under the radiator expansion bottle. Water gets in and the pins get corroded. Causes all sorts of odd behaviour that is not easily diagnosed. The obvious with your situation may be the engine harness connector. The other thing that can throw odd errors is water in the fuse box. The boxes are open on the underside and will let water in. (Jet washing NOT recommended!)