P0340 CEL / ESS / TCS / ESC

[anotheraznguy]

Well looks like my 800 mile jeep might have some issues. Wondering if anyone else had these issues before

This weekend was the first time we took it for a long trip and all these warning lights just happened to pop up. Read the code and P0340 appears to be cam position a sensor. After some googling i havent seen anyone else w/ a JL have this issue yet but it was an issue w/ JK's previously. Going to reach out to dealer and see what happens.

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[anotheraznguy]

In case anyone is reading this.

I took it to the dealership and the first thing they said was that there was no CEL. The code that i read was a P0340 which is camshaft sensor. The tech claimed that they pulled a different code for P0258b which was Vacuum pump. They replaced the vaccum pump and test drove it without issues. Within 40 miles of me driving to the next town over and back i was able to trigger the CEL again with the same P0340 code.

I dropped the car off with 867 miles on the odometer and it was returned with 940 miles the first time it went in for this issue and they decided to use half a tank of gas as well.

Now its the weekend and we are without the jeep once again and i have to schedule another service, have them waste more of my gas and rack up the miles on a jeep that i cant even drive considering i have 2 young ones with me.

@JeepCares

 

[UCF Knights]

No way should they be driving it 80 miles to check their work. Someone has some explaining to do.

 

[anotheraznguy]

So second trip to the dealer
9/18 dropped it off
9/21 Picked it back up

991 miles in and 1077 miles out

First trip they drove 85 miles
Second trip they drove 86 miles

so they have 171 miles so far

I test drove it again
30 miles south on hwy then 30 miles to return home

Within 15 miles south the ESS light turned on
at 30 miles i exited the fwy stopped the car and started it again to go back north
Within 6 miles of restarting the vehicle the Check engine light and ESS came back on.

While driving home i noticed that the voltage was 12.7 regardless of what i was doing. The only time it went above 13 V was when i was coasting at speed. If i was idle at a light the voltage would begin to drop to 12.5 V

When i got home i disconnected the negative cable and mesaured voltage at Large battery and Small battery
Large battery was at 12.68 and small battery was at 12.52

With the large battery disconnected i started the vehicle and the voltage was still at 12.7. I then revved it as well and the voltage did not increase at all.

So far the dealer has replaced a Vacuum pump and Cam sensor.

I now have to schedule another appointment but i believe the issue may be due to either the Secondary battery / Charging system / ECU

 

[Torero]

So second trip to the dealer
9/18 dropped it off
9/21 Picked it back up

991 miles in and 1077 miles out

First trip they drove 85 miles
Second trip they drove 86 miles

so they have 171 miles so far

I test drove it again
30 miles south on hwy then 30 miles to return home

Within 15 miles south the ESS light turned on
at 30 miles i exited the fwy stopped the car and started it again to go back north
Within 6 miles of restarting the vehicle the Check engine light and ESS came back on.

While driving home i noticed that the voltage was 12.7 regardless of what i was doing. The only time it went above 13 V was when i was coasting at speed. If i was idle at a light the voltage would begin to drop to 12.5 V

When i got home i disconnected the negative cable and mesaured voltage at Large battery and Small battery
Large battery was at 12.68 and small battery was at 12.52

With the large battery disconnected i started the vehicle and the voltage was still at 12.7. I then revved it as well and the voltage did not increase at all.

So far the dealer has replaced a Vacuum pump and Cam sensor.

I now have to schedule another appointment but i believe the issue may be due to either the Secondary battery / Charging system / ECU

Which code do you have now, this last time?

 

[anotheraznguy]

Which code do you have now, this last time?

Same P0340 code. Cam sensor that was just replaced.
But the low voltage battery could mean ecu or alternator. And having a bad ecu could cause the improper 5v voltage going to the cam sensor.

 

[Torero]

Same P0340 code. Cam sensor that was just replaced.
But the low voltage battery could mean ecu or alternator. And having a bad ecu could cause the improper 5v voltage going to the cam sensor.

I think your guess is right. I would recharge the batteries overnight. Clear the codes and drive it keeping an eye on that voltage. It may be a short somewhere, battery or alternator like you say.

 

[Jeepsk8]

There are threads explaining the voltage thing. Basically, it tends to charge while decelerating unless the batts are low. It does not operate the way older cars do so you are chasing the wrong thing. If the aux battery is not charging then the fuse matrix in the PDU is suspect (that is on the side of the fuse box where all the studs are that the big cables bolt to) or there is a relay that brings the aux battery online for ESS. Have you checked to make sure all the fuses are seated? As for the cam sensor, there have been reports of bad rocker arms and I think that threw a cam sensor fault.

 

[anotheraznguy]

Well i dropped it off at the dealer and sadly they didnt want to hear anything other than its a CEL. i explained to him what had happened and they totally ignored it cause apparently their word is the end all be all of knowledge. We shall see what happens but at this point i am not holding my breath

 

[Jeepsterfreak]

Well i dropped it off at the dealer and sadly they didnt want to hear anything other than its a CEL. i explained to him what had happened and they totally ignored it cause apparently their word is the end all be all of knowledge. We shall see what happens but at this point i am not holding my breath

Start researching lemon laws in your state, you might need it especially if you have incompetent dealer service department.

 

[anotheraznguy]

I am aware of lemon laws in the state and am 1 trip again to the dealership or another 2 weeks from having all the criteria met. What is the worse part about it is i explained to them in detail the issues and how to duplicate issue as well as pictures for over 30 minutes and the service writer just puts down "Customer states the ESS light came then check engine light came on & vehicle runs rought at idle"

@JeepCares

 

[Jeepsterfreak]

I am aware of lemon laws in the state and am 1 trip again to the dealership or another 2 weeks from having all the criteria met. What is the worse part about it is i explained to them in detail the issues and how to duplicate issue as well as pictures for over 30 minutes and the service writer just puts down "Customer states the ESS light came then check engine light came on & vehicle runs rought at idle"

@JeepCares

Use the dealer’s incompetence to your advantage if you want to pursue lemon law. Let them fix it unsuccessfully multiple times.

 

[anotheraznguy]

As for the cam sensor, there have been reports of bad rocker arms and I think that threw a cam sensor fault.

Test drove the car again and same issue they checked alternator / pcm / relays / battery
Replaced a few more sensors as well

Next step dealer is removing the top end cause they might suspect rocker as well. We shall see

 

[Jeepsk8]

Test drove the car again and same issue they checked alternator / pcm / relays / battery
Replaced a few more sensors as well

Next step dealer is removing the top end cause they might suspect rocker as well. We shall see

Ugggh. I hope they get it figured out.

 

[anotheraznguy]

So right at the 30 day mark for lemon law they "fixed" it and i have it back in my possesion

Will need to do some testing to see if the engine light comes back on. They were able to replicate the CEL when they had it

So after thinking it was electrical and testing pins and ecu and sensors they tore down the top end and front cover

Here is the lest of items that ended up getting replaced on the third dealer trip

Camshaft Sensor bank 1 and bank 2
right Chain Tensioner
both Timing chain guide
Tensioner
Camshaft Phaser
Oil Control Valve
New valve cover gaskets
New chain case cover gasket

We shall see if the CEL comes back.,at this point if it occurs again i will return to stock and proceed with lemon law.

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