Saturn Ignition Module

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Renzl
Posts: 1
Joined: Tue Oct 18, 2016 2:09 pm

Saturn Ignition Module

Unread post by Renzl » Tue Oct 18, 2016 2:12 pm

Saturn 2002 L100/2.2L had a misfire, coil pack replaced, runs fine but "service engine soon" light still on and P0340 code comes up. What could be the problem?

 

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carriedi
Posts: 2266
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: Saturn Ignition Module

Unread post by carriedi » Wed Oct 19, 2016 11:10 pm

so, you know you have a p0340 code. have you checked your cam sensor? Did you clear the codes and have this code return? Or did you always have this code? Is the misfire gone now? Need more information or you may want to check the cam sensor signal or replace the cam sensor
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Awnryprincess

Re: Saturn Ignition Module

Unread post by Awnryprincess » Fri Dec 09, 2016 1:09 am

Renzl wrote:
> Saturn 2002 L100/2.2L had a misfire, coil pack replaced, runs fine but
> "service engine soon" light still on and P0340 code comes up.
> What could be the problem?

Change your spark plugs and wires. The plugs took the code away but still had similar symptoms. Changed the spark plug wires next. When I did one of my coils was corroded so I cleaned that up.(poster indicates coil already changed out though). P340 code will trigger when you have a misfire on the 1 or 4 cylinder - there is no camshaft sensor (crank? I always switch the two -but whichever is with this code - the car doesn't have one). Car was still idling high and a little rough even after doing this. I went and had oil changed since I had bought it used - no further issues since and it actually runs quieter.


Post is probably old I understand but reply will be here for next person in case it's needed.

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carriedi
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Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: Saturn Ignition Module

Unread post by carriedi » Sat Dec 10, 2016 12:55 pm

Awnryprincess is absolutely correct. there is no camshaft sensor in this vehicle. There is a camshaft signal but it is based on the electronic ignition module. The ignition module delivers 5 volts to the cam sensor circuit when it sees #1 and #3 cylinders fire on their compression stroke. The ignition coil sends a signal to the ignition module that tells the polarity sequence and voltage amplitude of the 1/2 and 2/3 secondary ignition. The powertrain control module has an internal resistor tied to ground on the signal line in order to read zero volts when there is no signal from the cam circuit.

to make it short: the cam code is set when the powertrain control module does not see the any cam signal change in 35 crankshaft revolutions.

using a scanner you can look at the cmp counter and watch the counter. it should count up to 255 and then drop to 0 and start all over again. the counter will stop if there is a fault.

to get the P0340 code the fault must exist on the cam signal circuit, the brown and white wire, or low resistance on both 1 & 3 or high resistance on both 2 & 4 secondary ignition systems.

A missing cam pulse without a misfire may not affect engine operation...
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