I have a 2001 Dodge ram Cummins 24v AT with a check engine light codes : P1693, P0236, P0112, P1488. I brought it to a mechanic and he told me 3.7 volts are coming out of the ECM. I just want to make sure that maybe a short or something else before I invest in a new ECM. I also have a smarty tuner tuned to level 5.

Edited April 9, 20205 yr by Yonyip

Follow the troubleshooting for each code

 

https://mopar1973man.com/cummins/articles.html/24-valve-2nd-generation_50/51_engine/obdii-error-codes_94/

 

 

I would start with the 1488 code first.

So I cleaned all my grounds and still the check engine persists I also started with the p1488 and the first step I read 5 volts then to replace map sensor but I know the sensor is good because it is brand new so I stumped.

Did you clear the codes and they came back?

Yes they come right back instantly. 

Try returnig your smarty to stock and see what happens. You have a tech telling you you only have 3.7v at the ECM but have 5v at the sensor. Sounds odd me.

W-T ground wire mod? Did you check ECM and VP44 grounds?

I was also told that the oil pressure reading from the ECM is 0 but on the gauge cluster in the truck its normal could that be the cause? I noticed the wiring diagram for the truck its connected to the MAP Sensor and the 5v Supply?

Depends on the year. 2002 the oil pressure is a single wire. No tie to the +5V of the MAP. This was a change in the wiring in 2002. 

 

All information from the ECM like oil pressure is sent by the CCD network to the cluster. There is no connection between the cluster and the oil pressure sensor directly. 

 

Oil pressure sensor -> ECM -> CCD Network -> Cluster

 

 

Do the cluster test...

 

Edited April 30, 20205 yr by Mopar1973Man

If it comes down to it, I have a spare 01' 24v A/T ECM I took from a junkyard motor with blowby. I've had it sitting around as a spare for my truck as a just in case.