Hey fellas I got some issues maybe you all can help me solve. I been building a 77 crew cab chevy and installed a 97 12v and I've been working on the dodge harness and pcm to fit in the truck because I live in California the ref wants a working obd2 system so I've been busy chopping up the harness to work. I just have pcm and engine harness. I got most of it done and rigged up a obd2 port and got a couple codes pulled witch don't look good p1492 and p1389 the altinator is not charging and the grid heater never cycles I'm not sure if I'm missing something in the harness or if the pcm is toast. What do you guys think?

PCM works off of IAT temperature on the 12V for setting the grid heater to heating. Is the bulb blown? I know the IAT has to report below +60*F to turn on the grid heaters. Wait To Start light should come on every key cycle for a bulb check.

For code p1492 you need the spring loaded temp sensor that snaps into the original dodge battery tray. Or just find the two wires in the harness and connect a 10K ohm 1/2 watt resistor to the wires and tape into the harness that should fool the pcm and look like ~ 70 F.

Thanks guys for the reply I wound up replacing all new sensors iat and battery's temp sensor and crank sensor . I did send the pcm off to get the charging portion repaired and I'll see what happens when it comes back. The ca smog ref may want me to install a egr assembly I'm not sure if my engine came with it or without it I went to the dealership trying to get that info and the dealership is completely  useless and can't tell me that info.

On 10/4/2023 at 7:49 AM, metalmccue said:

The ca smog ref may want me to install a egr assembly I'm not sure if my engine came with it or without it I went to the dealership trying to get that info

I've only seen one truck in my time with an EGR valve on the 12V 6BT engine. I would check but typically the 6BT did not come with an EGR valve. If you do have to install a valve I would have to tell you a little secret on how to do it so it pass visually but the EGR doesn't flow any exhaust gases into the manifold. Sadly enough I will admit there is nothing gained by a EGR system on a diesel but enhanced wear and decreased MPG's. Just think if you introduce exhaust gases to a fire it going to reduce the bang of the fuel and not burn well.