QuestionQUESTION: Hi Pete, I have a 2000 Dodge Neon, about 2 weeks ago while I was driving the car would not accelerate then died and I was unable to get it to start. After some troubleshooting I found out that the fuel pump had gone out. It would not come on when I turned the key and no gas would come out of the valve on the fuel rail with the ignition on.
I found a used pump and replaced the old one yesterday. The car will still not start and I thought that it may not be getting any spark so I took one of the plug wires off and tested for spark and it was fine. I then read about how to check the error codes by turning on and off the ignition. The following codes are what popped up.
0340- No Cam Signal at PCM
1684-Battery has been disconnected within the last 50 starts.
Now before I tried the error code test I must say that I ran the battery completely dead trying to make sure there was no air in the fuel lines from replacing the fuel pump.
The one I am most concerned with is the No Cam signal at PCM. I did some research and found that this is caused by the camshaft position sensor. Could this be the problem with my car not starting and is it possible that a bad fuel pump caused this sensor to go bad or is it a mere coincidence that they both went bad at the same time? I still do not have the car running by the way but I plan on changing the sensor at the end of the week. Thanks for any help you can provide.
ANSWER: Hi Joseph,
The way the safety features of electronically controlled engines are designed, if the cam sensor was bad then the engine controller reacts to that to protect against an engine fire by turning off the spark coil and the fuel pump. The shutdown is done by the automatic shutdown relay. It will however not happen until 1 second after the ignition key is moved from off to run or start. So if you weren't looking to hear the fuel pump run for that first second you may well have thought the fuel pump was the problem. The dark green/orange wire to the spark coil is the one from the ASD that carries the 12V for a second (and the dark green/white to the pump from the controller), then drops out unless you start cranking over the engine AND the there are signals from the cam and the crank sensor reaching the controller. The pump cannot cause the sensor to go bad. So it might be the pump is OK, or it could have been coincidental, so test the pump on the bench to see if it is working.
You didn't say which engine you have so I am not certain on any help to give you for replacing the sensor. I have the '97 Neon manual that gives the steps for the 2.0 SOHC and DOHC engines. Write back and tell me which and I can pass that along to you.
The battery running down most likely caused the 1684 but in any case that code is usually not significant.
Roland
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QUESTION: Hey Roland, the engine is the 2.0 SOHC. If I am right the sensor should be on the right side next the battery and should not be too hard to change. I have not had a chance to check the old fuel pump but you think it was the sensor all along?Thanks again.
AnswerHi Joseph,
Yes, if you weren't listening for it when you turned the key to run, then you may have missed the 1 second operation. Listen for it now so you will have that for reference in the future.
The sensor is on the end of the cylinder head.
Disconnect the filtered air tube from the throttle body and air cleaner housing. Remove filtered air tube.
Remove the air cleaner inlet tube.
Disconnect electrical connectors from engine coolant temp sensor and camshaft postion sensor.
Remove brake booster hose and electrical connector from holder on end of cylinder head cover.
Remove camshaft position sensor mounting screws and remove.
Loosen attaching screw for target magnet to rear of camshaft.
Install:
The magnet has two locating dowel to fit it to camshaft
Install magnet and tighten to 30 inch-pounds
Install sensor and tighten screws to 80 inch-pounds
Place brake booster hose and electricals back on end of valve cover
Attach electrical connectors to coolant temp sensor and camshaft sensor
Install air cleaner and tubes.
This is from the '97 Neon manual. Good luck on the repair.
Roland
