QuestionQUESTION: -Approx 3 months ago my 2000 Chrysler Neon would not start. Mechanic had then said probably needed new computer(PCM). Got car towed home and considered selling for parts, but a few days later after having done nothing to it, it started and ran fine for 3 months.
-So, 3 months later same thing. I re-seated the start relay, tried again and it would "turn-over" every 5 or 6th attempt, but only run 20-30seconds. After this happened few times, wouldn't turn-over at all. Tried switching key on/off 3 times to get codes, but engine light didnt light up.
Measured 12v at one side of Starter Relay coil when ignition held on start, but on the PCM side of coil was not exactly 0v. (approx 0.2v). So inserted wire into coil (pin going to PCM) and with that grounded to chassis, starter turns over(cranks) but car won't start. Any advice would be appreciated. thanks
ANSWER: Hi Rejean,
The way to get the trouble code is "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window to see the mileage reading change to show any 4-digit numbers preceded by a P, or 'done' which means no codes were found. The engine light is not how it works in an '00 model year car, or if it is the key has to be in the 'on' position or it won't light at all.
Let me know what you learn that way.
Sorry for the delay but your question was just referred to the 'pool' where I just found it.
Roland
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QUESTION: Thanks for getting back to me.
I do remember seeing a "done" on the odometer a few days ago, but recently...nothing.
I borrowed an OBDIII tester and plugged into data connector under steering wheel this morning. It reports back that there is no communication. Checked data link connector with a meter and it does have 12v at pin 16.
Even oil/temp etc lights are not on...I think they used to be on when ignition in ON position.
I guess next step is to see if power getting to actual PCM.
ANSWER: Yes, check fuse 10 in the dash fuse box which should show 12V in the run position.
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QUESTION: -Fuse 10 checks out OK, and 12v to the fuse when ignition set to Run.
-12v and grounds check out OK at connector C1 and C2 on the PCM.
-Connector C1 Pin 36 on the PCM has continuity to the Starter Relay coil.
-12v and ground check out at the data link connector under steering wheel, but ODB reader says no communication link.
-When ignition to Run there are 6 beeps with "break?" and "battery" lights on but no engine light. After about 20 sec the engine light comes on and others go off. Odometer reads, radio works.
-Turning ignition to Start delivers 12v to one side of starter relay coil but PCM does not deliver ground to other side so no start. If I ground other side of relay coil, car will turn-over but not start. There is continuity from starter relay to the PCM(pin36).
-This model does not have security system.
-Either PCM fried, or is there something else that would cause PCM to not want starter to engage?
AnswerHi Rejean,
One typo?: I think pcm pin 36 should actually be pin 31. (ref: '01 manual)
The only thing that keeps the pcm from actuating the starter relay coil would be the p/n safety or clutch safety switch depending on which you have, and that is signalled by grounding pin 76 of the pcm. I don't know whether the lack of that ground would also prevent the engine from running which is also your problem when you by-pass the relay coil. It typically is just a starter relay safety switch and shouldn't have anything to do with no start. So the way the dash lights are behaving makes me too wonder if the pcm has gone bad, and of course the 'no communication' report on the reader is suspicious of that. Maybe the first mechanic was correct.
I haven't had many situations that I can recall where the pcm would not communicate, but if the wiring is verified from the data port to the pcm it would suggest the pcm is bad. I would verify data link 2 to pcm 59, 6 to 75, 7 to 65, and that 4 and 5 of the link are grounded. If all that checks and you still get 'no communication' then the pcm is likely no good.
Roland
