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Discussion Starter #1
Started my truck this morning and the MIL light was on...

:doh:

Plugged in my scanner and had the following codes.

P040B - Exhaust Gas Recirculation Temperature Sensor 1 Circuit Performance

and

P2509 - ECM/PCM Power Input Signal Intermittent

:confused013:

Has any had the P2509 signal and do you have any idea what caused it?

My truck goes in tomorrow to see the dealer with only 260 miles on the odometer...

:banghead:
 

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Discussion Starter #2
So nobody besides me has seen the P2509 - ECM/PCM Power Input Signal Intermittent code?

:confused013:

Maybe this is a good thing and once they fix it the code won't come back on a regular basis...

:shock:
 

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Hi Ken,

Where did you purchase your truck? I've purchased several vehicles from Junction Auto in Chardon and have always had excellent service there.

I'm not real sure about how they will feel about the deletes and mods that I have on this truck though.
 

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Discussion Starter #4
Hi Ken,

Where did you purchase your truck? I've purchased several vehicles from Junction Auto in Chardon and have always had excellent service there.

I'm not real sure about how they will feel about the deletes and mods that I have on this truck though.

I picked it updown at Salem Dodge. Junction had my business for a couple of vehicles a few years back but lately I have purchased elsewhere. Take care,

ken
 

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I have had the P2509 code before with my 07 5.9. Turns out both times where due to the batteries being low and when the heater kicked on it was enough to starve the computer of power I suppose. Both times they cleared themselves after running for awhile with the batteries charged up.
 

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Discussion Starter #6
I have had the P2509 code before with my 07 5.9. Turns out both times where due to the batteries being low and when the heater kicked on it was enough to starve the computer of power I suppose. Both times they cleared themselves after running for awhile with the batteries charged up.
Interesting... I find it hard to believe this is the issue because the grid heater battery is our auxillary battery, not our starting battery. Plus the PCM/ECM runs off a regulated (+) 5 VDC.

Thanks for the information and I will post up what the dealer says, if anything, tomorrow after I get my truck back.

:thumbsup:
 

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Discussion Starter #7
Kind of a waste at the Dealer today, they said the codes were intermittent so they just reset the MIL - I could have done that... :doh:

On the bright side, the falsh was upgraded to AS so maybe the problem will go away... :hehe:
 

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There is no seperate crank battery and grid heater battery. They are connected in parallel. So you draw and charge both battreries at the same time.
 

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Discussion Starter #9 (Edited)
There is no seperate crank battery and grid heater battery. They are connected in parallel. So you draw and charge both battreries at the same time.
While the batteries are in fact tied in parallel to the alternator, the auxillary battery connects directly to the grid heater circuit and the primary battery connects directly to the starter. I never said there were seperate batteries for starting and heating. Oh, and charge will be be a function of cable length, resistance of wire/connections, individual battery voltage, load current, etc...

:confused013:
 

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Ken
The ECM actually has 2 battery feed sources. One is a B+ (12V) that is connected to battery voltage at all times and another that "wakes up" the ECM on key-up. You are right the ECM does have an internal regulator that feeds most of the sensors +5VDC. But its source is B+ 12V. So if the battery voltage falls below a specified threshold- I'm not sure what that is for Cummins- it may set a low battery fault code. Additionally when the ECM goes below 6.9 volts it does an automatic internal re-set. The re-set is mostly transparent to the vehicle user- but a 6.9 event will also likely set a code.
 

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Discussion Starter #11
Ken
The ECM actually has 2 battery feed sources. One is a B+ (12V) that is connected to battery voltage at all times and another that "wakes up" the ECM on key-up. You are right the ECM does have an internal regulator that feeds most of the sensors +5VDC. But its source is B+ 12V. So if the battery voltage falls below a specified threshold- I'm not sure what that is for Cummins- it may set a low battery fault code. Additionally when the ECM goes below 6.9 volts it does an automatic internal re-set. The re-set is mostly transparent to the vehicle user- but a 6.9 event will also likely set a code.
Thanks for your explanation. :)

The supply side before regulation is definitely battery voltage and the regulator for the microcontroller will probably be 5 VDC since this voltage is still pretty standard for industrial flavor controllers. The majority of the sensor input ports are Analog to Digital Converters (ADC's) and must be limited to the micro's supply voltage, while some ports will be digital input/output (I/O).

I have a hard time believing both batteries were dead enough that their combined internal resistance allowed the supply voltage to drop below its lower limit.

The dealer stated the DTC's that were stored were just intermittent codes and could therefore be ignored - I don't buy that explanation...

I never saw a low battery voltage DTC.

Ken

:buttkick:
 

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If you haven't already done so (and have the ability to) check all connections including the negative side connections / straps to the engine, frame and body, more than a few folks with intermittent codes such as the one you mentioned have found something lose or incorrectly installed.
 

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Discussion Starter #13
If you haven't already done so (and have the ability to) check all connections including the negative side connections / straps to the engine, frame and body, more than a few folks with intermittent codes such as the one you mentioned have found something lose or incorrectly installed.
I haven't done any of the checks you have suggested yet, but I was really hoping the dealer would have checked and fixed the problem and not just reset the DTC's.

If the codes come back, I think I will push the dealer to fix it, though I will probably check/trace the signals out too.

Thanks,

Ken
 

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Interesting... I find it hard to believe this is the issue because the grid heater battery is our auxillary battery, not our starting battery. Plus the PCM/ECM runs off a regulated (+) 5 VDC.
While the batteries are in fact tied in parallel to the alternator, the auxillary battery connects directly to the grid heater circuit and the primary battery connects directly to the starter. I never said there were seperate batteries for starting and heating. Oh, and charge will be be a function of cable length, resistance of wire/connections, individual battery voltage, load current, etc...

:confused013:
Yours must be hooked up differently than mine then. I have large cables that connect both batteries in parallel for starting and using the grid heater. When crankning you use both batteries and when using the grid heater you use both batteries. They are in parallel for use on everthing.
Now that this has been said. My brother had a charging issue with his truck where the computer reads voltage from the dirvers side battery, but the charger is hooked the passenger side battery. I think this is the way he found it can't remember exatcly for sure. His problem was with loose parallel cabeling between the batteries and ground connections. It was causing him the same faults that you speak of. So check all your connections and see if that helps.

Andy
 

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Discussion Starter #15 (Edited)
Yours must be hooked up differently than mine then. I have large cables that connect both batteries in parallel for starting and using the grid heater. When crankning you use both batteries and when using the grid heater you use both batteries. They are in parallel for use on everthing.
Now that this has been said. My brother had a charging issue with his truck where the computer reads voltage from the dirvers side battery, but the charger is hooked the passenger side battery. I think this is the way he found it can't remember exatcly for sure. His problem was with loose parallel cabeling between the batteries and ground connections. It was causing him the same faults that you speak of. So check all your connections and see if that helps.

Andy
Andy, if you look closely at the (+) battery connections, you will see a single cable connected between one battery and the grid heater and a single cable connected between the other battery and the starter.

While an ideal wire has no resistance, and therefore no voltage drop when heavily loaded, there will be differing voltage drops between the 2 batteries when loaded since the cables are real and have a finite resistance. This means the batteries are really not connected in parallel since each battery will assume its own loaded voltage - this violates Kirchhoff's Voltage Law for a parallel circuit.

When I get some time I will check my system (+) and (-) connections, but finding and fixing whatever caused the DTC is really a Dealer responsibility.

Ken
 

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I am a master electrician and I know what parallel connection is. I am not trying to get into a pi$$ing match. The batteries are connected in parallel. They just tap off one battery for the connection. Trust me it draws off of both batteries. I am just trying to help a bro out. I hope you can figure this one out. I doubt you will have much help from the stealership unless it is a maintained problem or until something fails.
 

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Discussion Starter #17
I am a master electrician and I know what parallel connection is. I am not trying to get into a pi$$ing match. The batteries are connected in parallel. They just tap off one battery for the connection. Trust me it draws off of both batteries. I am just trying to help a bro out. I hope you can figure this one out. I doubt you will have much help from the stealership unless it is a maintained problem or until something fails.
Since you are a master electrician, why don't you measure each battery voltage drop, and the current delivered during both conditions, (start and grid heat) and get back to me.

The battery voltage and battery current measurements must be exactly the same during both conditions or the batteries are not actually in parallel. I'll bet any amount of money you want these measurements will be different.

While the schematic shows the physical connections between components, it does not take into account the non-ideal parasitic properties and add them to the circuit model which is needed for analyisis.

Again since you are a master electrician, you must have figured out what size cable/conductor to use use in each AC Voltage branch based on the load current draw and allowed voltage drop across the branch.

The engine compartment is no different when heavily loaded, and while the schematic connections appear to make everything behave the same, real world physical element properties dictate differently.

Oh, and I'm not trying to get in a pissing match either.

:thumbsup:
 

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Since you are a master electrician, why don't you measure each battery voltage drop, and the current delivered during both conditions, (start and grid heat) and get back to me.

The battery voltage and battery current measurements must be exactly the same during both conditions or the batteries are not actually in parallel. I'll bet any amount of money you want these measurements will be different.

While the schematic shows the physical connections between components, it does not take into account the non-ideal parasitic properties and add them to the circuit model which is needed for analyisis.

Again since you are a master electrician, you must have figured out what size cable/conductor to use use in each AC Voltage branch based on the load current draw and allowed voltage drop across the branch.

The engine compartment is no different when heavily loaded, and while the schematic connections appear to make everything behave the same, real world physical element properties dictate differently.

Oh, and I'm not trying to get in a pissing match either.

:thumbsup:
I know what you are saying. According to the logic you are applying no two batteries could ever be put in parallel unless they were a matched set that the same internal connection and had a true 0 ohm connection between them not really realistic in any automotive application. All I am stating is the batteries are physically connected in parallel. One battery is connected to the charger and the other battery is connected to the voltage pickup sensor. Check your connections real close as this has caused problems for other people. I know you can't argue that they are physically connected in parallel, because of the cabling connections. :S::S:
 

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Discussion Starter #19 (Edited)
I know what you are saying. According to the logic you are applying no two batteries could ever be put in parallel unless they were a matched set that the same internal connection and had a true 0 ohm connection between them not really realistic in any automotive application. All I am stating is the batteries are physically connected in parallel. One battery is connected to the charger and the other battery is connected to the voltage pickup sensor. Check your connections real close as this has caused problems for other people. I know you can't argue that they are physically connected in parallel, because of the cabling connections. :S::S:
:agree2: they are physically connected together and I stated that in my above post.

:beer
 

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Sheesh stop over analyzing the batteries hooked up in parallel. It's not enough drop to be any kind of issue. Both batteries supply power to whatever needs it. It's not like there is a diode in the battery cable.
 
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