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2003 PT cruiser not starting


14 replies to this topic

#1 McFinnigin59

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Posted April 30, 2013 at 05:16 am

I have a 2003 PT cruiser Limited,love this car, but it won't start! Nothing happens when u turn the key,except for the normal lights and bells, the battery is new,checked the stater(car will start when u jump the starter) checked the starter relay and fuses,at one point i was able to disconnect the battery wait a min the hook the battery back up and the car would start-- but it won't do that now. The car has had the timing belt replaced and some other work done to it by the first owner( i am the second owner) Tried to get codes but none show up,all it says is "done",can anyone help me with this problem?

 

 



#2 AC TC

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Posted April 30, 2013 at 06:35 am

Neutral gear/ clutch depressed switch?

Ign switch?

As i understand turning the key to start pos wont make the starter run.



#3 Doug in Florida

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Posted April 30, 2013 at 06:42 am

I was thinking either the ignition switch or the PRNDL switch (assuming an automatic transmission).



#4 McFinnigin59

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Posted April 30, 2013 at 07:45 am

it is a automatic, tried starting in neutral- nothing 



#5 Bob Lincoln

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Posted April 30, 2013 at 07:51 am

How did you verify that the starter relay is good?



#6 McFinnigin59

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Posted April 30, 2013 at 09:55 am

i swapped it out with another relay that was the same as the starter relay



#7 Bob Lincoln

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Posted April 30, 2013 at 01:35 pm

OK, that works if you are sure the other relay was functioning normally.

 

This may go back to the neutral safety switch, then, but more likely a bad ignition switch.



#8 McFinnigin59

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Posted April 30, 2013 at 01:58 pm

all the relays in the pdc are the same ,all have the same numbers and everything. how can i test the ignition switch?,and do u think it could be the powertrain control module? is there anyway of testing that? i read somewhere that pt cruisers had a problem with the powertrain control modules which would make the car not start,does anyone know of this or heard of it or had it happen to them? I'm living on a fixed income so i dont have a lot of money to spend on something that expensive and not have it be that part,especially an electronics parts cause i wont be able to return them.    thanks.



#9 B10alia

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Posted May 2, 2013 at 04:21 pm

The current for the starter has nothing to do with the ECU. There's a difference between a "no-crank" and a "no-start". You could remove the ECU from the vehicle, and the starter would still crank.

Here's a brief rundown of what happens when you turn the key:

The ignition switch has a momentary switch in it that closes a circuit when the key is turned to START. This energizes the starter relay coil. The coil turns into an electromagnet, pulling the relay armature towards it and completing another circuit to the starter solenoid. The starter solenoid is responsible for engaging the starter motor drive gear with the flexplate or flywheel, as well as closing another set of contacts. This second set of contacts is what actually supplies the current to spin the starter motor. 

Why such a Rube Goldberg means of turning the starter? It comes down to current, and the size of wires and switches needed to carry it. The starter motor requires a couple of hundred amps to spin the motor over. This is why the starter motor has such huge cables running to it. In order to have a low enough resistance to carry the current without welding themselves together, the solenoid's contacts are pretty big. However, the solenoid requires less current to operate, which is small enough that it can be switched by the starter relay. Again, the relay is a pretty beefy piece of equipment compared to the ignition switch, but, again, it takes less current to operate than it's capable of switching. This current is small enough to be carried safely through the small wires and contacts in the ignition switch.

I would get a good wiring diagram and probe the coil terminals of the starter relay socket. You should get about 12V there when the key is turned to START. If you get nothing, there's a problem with the switch or wiring going to it. If you do have 12V, check the starter solenoid contacts. You should have 12V there, too. If you have 12V all the way down, try hitting the starter with a broom handle, plastic mallet, hammer handle, etc. If this gets the car to start, the starter solenoid is probably the cause of the problem. No solenoid action, no starter current.

I would put the ECU way, way down on the list. I can't tell you how many people on here have replaced the "computer" because the car was acting strangely and they didn't bother checking grounds. ECUs themselves rarely fail for no apparent reason unless they've been burnt, overheated, submerged, etc. They're really not wear items. 9 times out of 10, the problem is in the wiring somewhere. Replacing the ECU usually only lightens your wallet. And no weight reduction anywhere helps a car that isn't moving...


Edited by B10alia, May 2, 2013 at 04:22 pm.


#10 John Wood

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Posted May 2, 2013 at 04:33 pm

B10alia
Chrysler made a change in the starting circuit in most of their cars several years back (even including my 96 minivan). The circuit does pass through the ECU logic. The ECU looks for sync pulses and if it sees them, it will not let power pass through to the starter relay (it actually throws a ground on the starter relay coil to close the circuit when it allows starting). The purpose for that is to prevent you from operating the starter when the engine is running.

That is not likely the problem here but it could be.

I'm thinking it could be the typical bad solder joints in the console, but that is just a guess. Further troubleshooting is required including a simple test to bypass the starter relay to make sure it spins.

#11 ImperialCrown

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Posted May 2, 2013 at 04:36 pm

 The PCM does have a hand in providing the relay coil ground in order to actuate the relay contacts to energize the starter solenoid to crank the starter over.

The PCM has to give cranking permission first by being sure that the engine isn't already running and that the transaxle is in Park or Neutral.

 

0996b43f8022db6a.gif


Edited by ImperialCrown, May 2, 2013 at 04:39 pm.


#12 John Wood

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Posted May 2, 2013 at 06:21 pm

Using IC's diagram as a guide, you will want to check for voltage on the yellow wire going to the starter relay coil when the ignition switch is turned and held in the 'start' position.. Since this is a PDC, you probably can't easily identify the yellow wire so you will need to probe each of the sockets that the starter relay plugs into. One of the sockets should show voltage when the key is moved to start and that would confirm that the ignition switch start contact is functioning. You will need a helper to operate the key while you probe the sockets for power.

I would have thought there would be a code for "battery recently disconnected".

Edited by John Wood, May 2, 2013 at 06:24 pm.


#13 B10alia

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Posted May 2, 2013 at 10:48 pm

Huh. I guess I need to stick my head up a little more, I'm still stuck in the EEK era... who would have thought that an ECU would have MORE power than your average calculator?!?

That being said, I still think it's a HUGE stretch to say the ECU is at fault. I would check the simple hardware first before I even looked at the computer. 



#14 ImperialCrown

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Posted May 3, 2013 at 05:38 am

Yeah, grounding the relay pull coil through the P/N or clutch safety switch was the way it used to be done, but now they have a 'smart' ground method. I also doubt that the PCM (ECM) is at fault. It is the last house on the block when it comes to any diagnosis of this sort anyways. If the PCM is not providing a ground for the relay, it may be because it is being told not to by the P/N safety switch or TCM. A faulty P/N safety switch is rare on a 41TE transaxle, but may have to be checked in the diagnosis if we have to go that far. Following the wiring diagram, check for your 12 volts at the B4 and B5 relay socket terminals. Jumping 12 volts to terminal B1 should crank the engine. I don't think that you will see the 'B' numbers printed anywhere on the plastic in the PDC or on the relay itself. They may be identified like this:

 

sscully-albums-misc-picture28323-bosch-auto-relay.jpg

 

2009-10-28_214400_ISO_40_RELAY_TERMINAL_ID.png

 

relay.jpg

 

B1=87

B2=86

B3=87a (not used)

B4=85

B5=30

When they state 'Normally Open' (N/O) or 'Normally Closed' (N/C), that is the switch state of the relay at rest with no current applied to the actuating coil.


Edited by ImperialCrown, May 3, 2013 at 05:42 am.


#15 serry

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Posted July 22, 2013 at 09:07 am

When I change my battery in my PT Cruiser will I have to reset codes or something.? Iam having a problem posting new heading




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