Check engine light after dead battery

[MJ.STIGER]

I went to the coach that was in storage. Had some dead batteries I was able to get the unit started everything checks out OK. Last trip was four weeks ago  

Now that I have it started up and running and charging I’m getting a check engine light. 

 

Any ideas how to diagnose the check engine Light. I’m wondering if the batteries are still not charged and voltage is incorrect?

[96 EVO]

3 minutes ago, MJ.STIGER said:

 

 

Any ideas how to diagnose the check engine Light. I’m wondering if the batteries are still not charged and voltage is incorrect?

What is your Aladdin reading for chassis voltage?

[DavidL]

Like 95 Evo is suggesting, ensure your battery voltage is correct.

If not, try shutting down all batteries, charge, and reconnect all to do a "clean reboot".

Hopefully all that ails goes away.

If the Check Engine light is still on, it's possible if the issue is gone that it will auto reset after a few drives.

Best would be to invest in a scan tool compatible with your powertrain and pull the codes for much more specific info.

Post your codes on the forum.

Edited August 12, 2023 by DavidL

[Dr4Film]

Eliminate your first problem by installing a battery charger onto your chassis batteries and get them fully charged. Then do the house batteries to get them fully charged.

Now see if your check engine light issue has been resolved.

If not, then proceed with further troubleshooting.

[MJ.STIGER]

Thank you for the replies. I think I’ll invest into a code reader as well always good to have.

I am in favor as well of getting the batteries charged up and cycling to see if it goes away.

Just seems odd, that it followed the dead battery. And I didn’t have it before.

[DavidL]

Most vehicles have a code for low battery.  And typically it sets multiple codes as each ECU complains and sets it's own code.

Odds are, thats all it is.

[MJ.STIGER]

After running it for a while and taking to have the Sofa looked at. It has cleared the check Engine light.

Now to do what i have the parts for. Connect 100watt solar charger to it. And find out why it died when only sitting 3 weeks. Must have some draw that i am unaware of. 

Weird thing is i turn the House disconnect of with the main switch. And those seem to have been dead as well. otherwise i could have used the Boost switch to fire up the coach. I did turn both Coach Batt and House Batt off. Strange was the lock unlock remote still worked. I would have thought those 2 switches would kill everything. 

[Dr4Film]

Possibly your disconnect switches are not working properly.

[Ivan K]

There are things that are not controlled or turned OFF by the main switches, on mine anyway. For instance my inverter, CO and LP detectors, engine and tranny brains. Should be minimal draw but over time it would take the batteries down. Your wiring diagrams should tell you if that's the case.

[Tom Cherry]

48 minutes ago, MJ.STIGER said:

Thank you for the replies. I think I’ll invest into a code reader as well always good to have.

I am in favor as well of getting the batteries charged up and cycling to see if it goes away.

Just seems odd, that it followed the dead battery. And I didn’t have it before.

If the engine will run and you get started, start your generator.  You have a BIRD or Bi Directional charging system.  If you had power at storage, the batteries, both House and Chassis should have been charging.  The Big Boy Boost selenoid (biggest one back in the RRB) should have been “humming” and hot to the touch.  That is NORMAL.

My feeling is that is is riskier to pull batteries and charge them or take them to be charged.  When you drive, the alternator charges them.  NOW, you can shut  off the engine.   Then go back, assuming the inverter is charging and you see Bulk and maybe at 60 Amps or Absorb snd maybe 30 Amps or even float.  If the BIG BOY is hot and humming….then the chassis should be charging.  Turn on the ignition….do NOT start the engine.  The dash voltmeter or the Aladdin should be reading the same voltage as the Inverter remote.  If it is reading maybe 12.5 or so, then the Big Boy contacts need cleaning.

My simole solution is a jumper cable between the positives….and that is the easiest way to charge the chassis….assuming the Big Boy is not passing the House battery current.  Let the genny run for maybe an hour or two….then they will be recharged.  

You need to do some voltage measurements later on to determine that the BIRD system is working.

1 hour ago, MJ.STIGER said:

After running it for a while and taking to have the Sofa looked at. It has cleared the check Engine light.

Now to do what i have the parts for. Connect 100watt solar charger to it. And find out why it died when only sitting 3 weeks. Must have some draw that i am unaware of. 

Weird thing is i turn the House disconnect of with the main switch. And those seem to have been dead as well. otherwise i could have used the Boost switch to fire up the coach. I did turn both Coach Batt and House Batt off. Strange was the lock unlock remote still worked. I would have thought those 2 switches would kill everything. 

You have, probably, special two circuit cut off switches.  Two large terminals and two small ones.  They must be hooked up.  Some folks buy the wrong disconnext switch.  Only 2 large terminals.  That kills power to the board that controls the boost.  The board that controls the Big Boy has at least 3 functions.  One is that is turns ON and OFF the salesman solenoid.  Two…it controls the Boost which is actually the Big Boy.  Three, it monitors the charge on both sets of batteries and turns ON or OFF the Big Boy for BIRD or Bi Directional charging.

I started a post earlier and just finished.  Focus on using the generator with a simple Jumper cable to recharge the Chassis….then let us know and there are steps, with a VOM to determine IF the control board is OK.  That is a common faikure item…but might be OK.. and needs troubleshooting.

[MJ.STIGER]

Yes, I will have to dig into the cut offs. I do have a big boy. I think it is functioning correctly. I did end up getting the generator started first and running that which charged up the batteries.

Yes, I will have to dig into the cut offs. I do have a big boy. I think it is functioning correctly. I did end up getting the generator started first and running that which charged up the batteries.

 

Need to wrap my head around the charge circuit for both batteries. I think I might take the big boy out and check and clean the contactors just for safe measures. 

[DavidL]

As part of your diagnostics, I would suggest

Picture document all connections to all batteries.

Inspect.

Clean the battery bay.  I use a powerwasher.  My OCD gets my powerwasher trigger finger nervous when I see people post pictures of their battery bays.

Dry

Mark / label all connections

Disconnect all

Clean all connections and battery posts.

Rewash to get rid of any acid laden corrosion.

Recharge batteries

Test all batteries individually.  Replace as needed.  Best is always to replace the set so they are balanced.

Connect all again.

Retest that all is good.

The above is just good maintenance that prevents issues that crop up when you are on vacation and not within range of tools / time.

Edited August 13, 2023 by DavidL

[tomevansfl]

If you decide to buy a code scanner/reader, make sure it is capable of use on heavy duty trucks/semis. Also, confirm you have a 16 pin OBD II port on your rig. If you have a round port, count the pins in it and make sure the scanner comes with an adapter that matches your your rig’s pin count. My scanner came with a round 9 pin adapter but my Diplomat has a 6 pin port.

You can order an adaptor that has both such as:

OBDII 6Pin 9Pin J1708 J1939 Cable for Truck https://a.co/d/iOXy6WT

The scanner I have is:

HUMZOR OBD2 Scanner Diagnostic Tool, Car/Heavy Duty Truck Engine Fault Code Reader, NC601 Supporting 16/9 Pin Interface Read Code Erasure Code, Compatible with Light and Heavy Truck, 2 in 1 Scan Tool. https://a.co/d/dwYJPSn

Not sure of the quality yet. I haven’t had it long enough to judge. I believe it is made by NEXAS.