1998 Dodge Ram Dodge Ram 1500 code P1392

TOFAST4US10

MEMBER
1998 DODGE RAM
V8
2WD
AUTOMATIC
198,000 MILES

I have a truck that I purchased and it was throwing code P1391, Intermediate Crankshaft or Camshaft Position Sensor Failure.
Here is what has been done to the truck so far and has not worked
2 Crankshaft Position Sensors
3 Camshaft Position Sensors
1 Powertrain Control Module
New Distributor, Coil, Plugs, Wires, Cap & Rotor
1 New Distributor

The truck has been to a small time mechanic and a five star Dodge dealer both of which could not diagnosis it.

It also has another problem the speedometer dosen't start to work until 30 mph and the brake light is on. It has new pads and shoes and brake fluid so I know that isn't the case. The Dodge dealership said that they could fix this with a new speed sensor so they put one in (and charged me for it) but it didn't work and after that they said it couldn't be diagnosed either.

Any help would be greatly appriciated, if your answer is correct I will gladly donate money to you but I've already paid over $500 and had a lot of work done (and done a lot myself) for incorrect answers.

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,644 POSTS

Hi:
It sounds like you have been working on this. Honestly, I can't tell you a specific part to replace. However, based on what you are going through, I can add my 2 cents. I have been working on cars for 30 years, so I'll do my best to help.

Based on everything you have mentioned, I feel you are dealing with a couple different problems. The concern is the code, PO1391. If you have replaced them several times only to come back with the same problem, they are not the cause. I need you to check wiring for continunity from the sensor to the PCM. The code you are getting is telling me that they work and then they don't. My guess ( at this point) is you have either corrosion as an issue or the wiring internaly is partially broken. When you check, move the wire around to see if there is any change or evidence of a break in the wire that would either cause a loss of continunity or an increase of resistance. Also, check the plug on the PCM to make sure nothing is bent, pushed loose, or corroded. I don't believe there are any splices in the wiring from the sensors, but that would be another thing to check for. Many times I have taken apart wiring harness to find a "Factory Splict" that has corroded and caused the problem.

Check and let me know what you find.

Joe