Dodge Repair/'01 2.7L LH Intrepid: speedo/engine output irratic
In late June 2013, took my 2001 Dodge Intrepid SE 2.7L in for problem. Wracked my brain, cannot remember why or what, but engine code indicated the PCM (Power Control Module) was faulty and the mechanic found that a Fuel Injector had gone bad as well and was dumping fuel onto the PCM. This was replaced at a cost of almost $1300. Drove fine and flawlessly until Aug 2, 2013.
On this day, I noticed the speedometer was not working at all shortly after leaving the house. Then a couple more miles and the car began to lose power drastically, stalling, but not stalling out. One time during a moment of stalling, the auto-door locks re-engaged (possibly because of the sudden deceleration). It did this intermittently another mile until I turned around and headed home, dropped off passengers and then took car up to garage (near home) and described the problem and left it. A week later, they could not get the car to replicate the same problems I had experienced (with witnesses in the car at the time) they had diagnosed from the engine light code, and replaced the Output Shaft Speed Sensor (another $175). Two minutes later, while waiting at the stop-light leading out of the parking lot adjacent to the garage, the engine light came back on, and shortly after, the speedometer started acting up, going from ceasing to function to wildly taching back and forth) while the engine began again stalling and power falling off, but not stalling out altogether. Drove around another 10-15 minutes as it continued intermittently stalling, stopped back at the garage (the mechanic had already left for the weekend)and told the shop attendant that it was again doing as before. Drove home, decided to see if it continued on, drove it out to dinner and back without ANY problems, speedometer worked fine, no stalling. Next day, decided to drive again and see if it occurred again. Drove to shopping center on way to a friends, drove perfectly again, Shut off engine, went in store, came out and started up fine, and as I was leaving the parking lot, the speedometer ceased to function/began wildly taching and the commensurate engine stalling began again. This continued all the way to the friends house, about 10 miles. Car sat for several hours before I returned home. On way home, speedometer did not work AT ALL, no taching, no movement whatsoever, and if the car stalled at all, I either couldn't notice it or it did not stall at all... So now, I am preparing to take it to the garage again... Any ideas on what may be the culprit of this, or has anyone ever experienced these conditions before???
I would ask that the mechanic check the output speed sensor to see that the correct sensor was used (the input and output sensors look similar but are not interchangeable) and that it was installed properly in the transmission. Then he should also check the wiring of the sensor:
The pulsing signal from the vehicle speed sensor goes from the transmission to the powertrain (engine) control module and then after being digitized at the pcm is sent to the instrument cluster. The fact that only the speedometer reading is impaired suggests that the problem is either in the wire from the transmission to the pcm or inside the speedometer, rather than to the digital communication system or its wires. But you also have the stalling problem which could be due to almost anything. However the pcm does take into account the vehicle speed in its control of the engine so it may be that a fault in the wires connecting the speed sensor to the pcm may be the cause.
I would start by checking the continuity of the light green/white wire from the speed sensor plug (pin 2) to pin 14 at the black plug of the pcm and also checking the dark blue/black wire from that same plug (pin 1) to pin 13 at the pcm plug. Shake the harness gently while checking for continuity (zero resistance) and also check that there is not a short circuit between the two wires.
If those check out, then because the symptoms appear to be simultaneous it is likely that there is a single cause. The chances are better to solve the engine stalling as it will likely also solve the speedometer:
Have you tried to use the ignition key to readout the pcm memory for fault codes? Turn the key: "on-off-on-off-on and leave on" doing that in 5 seconds or less elapased time. Then watch the odometer window in the speedo for the mileage reading to be replaced by any 4-digit numbers preceded by a P. Let me know what you find and we'll go from there.
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