Low voltage to the ECM, OR a load on the ECM that exceeds the factory rating will do all sorts of bad things I'm told.
I have a Jacobs Exhaust Brake Kit for my 2006 Dodge diesel truck with manual transmission. I haven't installed the kit, as it came with the wrong harness. Last week I called Jacobs about it and talked with a technician of theirs. Very smart and very experienced. He sent me the correct part, but while on the phone, we discussed the set up. The harness runs a relay that controls a solenoid on a vacuum pump. The solenoid on the vacuum pump only draws .8amps and I wondered why a relay was needed instead of just wiring straight to the solenoid. What happens is, the ECM supplies a ground for the relay. (Only when my foot is off the throttle, and other conditions) The relay only needs .25amps. Jacobs worked with RAM to eliminate the relay and get permission to pull .8amps, not just .25amps. RAM said no, there was not the capacity in the ECM to supply that much current to the manual transmission Cummins diesel engine. To do so would drop the voltage and cause problems. So, you see, even .8amps of extra load on the power for the ECM will cause problems and RAM knows it, so they denied the design to bypass a relay to Jacobs. This is why Jacobs can not build a exhaust brake for the 2006 RAM diesel truck with an automatic transmission. Seems the ECM has extra load already on the ECM for their automatics and can't even handle .25amps extra to run a relay to work the Jacobs Exhaust brake.
It doesn't take much wiring resistance to drop .25amps. If I had that vintage dodge in a automatic diesel, I'd be really careful about the connections and loads as they pertain to the ECM.
I hope that makes sense. It explains to me that you very likely had a low voltage at the ECM and anything that routed through it, a sensor to the low pressure pump for example, could trip the minimum voltage and cause the ECM to act erratically.
I see you have a 2006 RAM diesel with an exhaust brake. Is it wired to your ECM? Is yours a manual or automatic? What brand brake is it?
