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[DarthLowen]

Hi all,

Just when you thought all was good (enough), this happens. So, it's a WJ which already has starting issues and intermittent airbag light issues. So this morning, took a minute to get started (already swapped the injectors, so pretty sure that's not the issue anymore), made a short trip to the store, upon arriving at the store I parked the car and sat in it with the engine idling (letting the battery charge a bit further) when all of a sudden it stalled and the 'check gages' light came on. The starter motor still spins the engine, but it won't start anymore. Checked the engine bay to see any obvious disconnected plugs, nothing, checked the battery voltage, was a bit on the low side but still plenty strong enough to turn the engine over as it should. The gauges on the dash all look ok, voltage showing a tad bit on the low side, but that's in fact the case. Oil level is high enough (pressure even goes up when cranking), fuel tank is full (and the gauge is reflecting that).

Any ideas would be greatly appreciated as always!

The airbag light suggests electrical issues, so I do believe there's a bad connection somewhere, I just hope someone can point me in the right direction!

PS: my OBDII tool shows a warning sign, but doesn't show me any stored nor pending codes, it's an Autel AutoLink AL301. Is there a better OBDII tool for these cars?

Cheers,
Nic.

[DarthLowen]

Quick update, I did the ‘ignition 3 times on/off trick’ to read the codes through the instrument cluster and came up with these:
P0702
P0836
P0620
P0243

I also did the ‘gauge check’ routine (keep odometer reset pressed while turning ignition to on) and all gauges work as expected.

[bgbazz]

Start with the easy stuff first...check the battery connections which should be clean and tight., then take her for a long drive and make sure she gets up to operating temp and stays there for half an hour or more. This should ensure the battery gets charged properly...a short trip to the store, then sitting with the motor idling for a while is no good at all!  Most alternators won't charge much below 1400 RPM, some need higher than that. My battery (4+ years old, will show 12.1 volts, even after sitting for 10 days or more when the temps are down around minus 10) and the car starts easily, every time. eg. the outside temp, right now, is minus 12 and it is snowing like crazy and I haven't used my diesel Golf for more than a week, but I bet she would start within 10 seconds. (should have mentioned that she is 21 years old).

As I mentioned....start with the battery first. 

[DarthLowen]

For sure I'll charge her up as soon as I have her towed back home, but it doesn't explain why the engine stalled, check gages light came on, etc. There's something more going on and it's driving me crazy because you can't just pinpoint an electrical problem like you would a good old mechanical failure...

PS: are you trying to tell me I should sell my WJ and get a VW instead? I'd love to see a Golf pull a trailer with 2 horses in it! 
Well, on the other hand, a broken down WJ probably won't get the job done either...

[bgbazz]

 

You answered your own question.

[Dave69]

a modern car wont start if the battery is below 11 volts due to the current draw required by all the electronics. So putting the battery on a 240v or mains supplied charger will help. Also if you have one of the new generation chargers which can recover a battery and have a varying charge rate will help.

A car charger system does not charge the battery as many people expect, the alternator gives a feed charge to the battery at 14v during normal running and approx 12 volts during idle. This isn't enough to give a "full charge while driving" so an external charge helps wonders.

Cold weather is a battery killer, hence why new cars have little insulated jackets around batteries (which are then binned during service etc and not replaced).


Just running through the error codes you have identified and most can be ignored due to a cascade error effect as the system conducts its checks, the error code that jumps out for me is P0620

PO620 Generator control circuit (generator aka alternator)

OBD Code P0620refers to

The PCM uses the generator turn on signal circuit to control the generator. A high side driver within the PCM allows the PCM to turn the generator ON and OFF. When Generator operation is desired, the PCM sends a 5 volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the Generator is enabled by the PCM, the voltage regulator controls generator output independently of the PCM. Under certain operating conditions, the PCM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit.

Symptoms
Possible sumptoms of OBD code P0620
- Engine Light ON (or Service Engine Soon Warning Light)

Causes
Possible causes of OBD code P0620
- Failed Generator/Belt - Battery charge - PCM controlled generator - PCM failure - Open or short generator circuit The Error code is generally activated on detection of the following conditions: The PCM has fault detection circuitry which monitors the state of the generator turn on signal circuit. If the fault detection circuit senses a voltage other than what is expected, this DTC will set. The voltage regulator also contains fault detection circuitry. If the regulator detects a problem, the regulator will ground the generator turn on signal circuit, pulling the voltage low. This also causes the PCM to set the DTC


this site may help with some things http://www.ausjeepoffroad.com/forum/showthread.php?t=140297

and this

https://www.troublecodes.net/pcodes/p0620/

[DarthLowen]

Thanks for the elaborate description, I did forget to mention that I replaced the alternator last year because it was faulty (didn't 'charge' the battery anymore). I didn't reset the codes afterwards since my AL301 apparently didn't find anything wrong. So maaaaaybe that's just still a leftover from then... (fingers crossed)

Yesterday I measured 12.1V ignition off (which I find a bit low) and 9.6-ish volts while cranking (which is ok). That's why I'm no too afraid of the battery right now. It's charging as we speak, I'll try starting again in a few hours but I don't have much faith given the previous no-start troubles that led to me swapping the injectors.

My daily driver is a new Mercedes C300e (hybrid, god I lOVE that car!), I used it to tow the Jeep back home. My first time ever towing a 4x4 with a Hybrid, made some heads turn too 

[Andyp]

As I've been working from home more my WJ hadn't been used as much. It ended up not starting one morning so I took another vehicle. Next day I jump started it and left it running for the best part of 2 hours. The next time I tried to use it it started but the lights were dim and it stalled in neutral at the post box at the end of the road. It started again and my drive was another 46 miles each way so it seems to have been fine since. I've made sure I only use it for longer journeys since. I just thought I'd share as it sounds similar, apart from mine started again.

[DarthLowen]

Don't get me wrong, I know that longer trips are better for the battery, I'm just not 100% sure that's the main issue here. Thanks for sharing anyway, it re-confirms the importance of a decently charged battery. Just tried firing it up and again...bupkis...

[daggie]

I've just been through this non starting shit on one of ours, thought it was an injector at 1st, nope it was the glow plugs. It wouldn't start even if it was hot 

PS batteries on WJs are critical !

[Dave The Sparky]

Is this a cold weather thing? how old is the diesel in your tank? 

[DarthLowen]

Glow plugs? Isn't that just a helper thing? I always thought that the engine's compression should be adequate to light the diesel (especially on CRDs)? I'll add it to my list, these things are cheap enough anyways it seems. I was planning to get my battery checked sometime, I'll move it up the prio list.

The rough-starting is unfortunately not a cold weather thing, it improved when I replaced the injectors (especially in the beginning), but it never really cured everything. The diesel is not that old, a few weeks tops. The car does (did) 200km+ per week, so it gets refreshed often enough imho.

[Dave69]

for CRD injection engines, the glow plugs are only used with a temperature circa -10 degC and lower. normal temp starting should be good due to the atomizing pressure and a good cranking speed, another reason why the batteries are so expensive and have a high CCA value

[Dave The Sparky]

Going off your initial post this has to be either an electrical gremlin or fuel related as it was running for a little while before it cut out on you.
 
If it cranks over and takes a while to start normally is there enough diesel getting up to the engine in the first place?.
Its not something as simple as a perished/collapsed fuel hose or a bad seal on the filter where it can draw in air is it?
Diesel filter may be blocked, Do these things have a lift pump on them? is it that playing up?.

Just something else to think about thats all 

[DarthLowen]

It's definitely either a fuel and/or electric thing. After charging the battery up, it runs off of starting fluid...
I had it towed to the dealer, I don't have the time to start playing the guessing game. They'll run the diagnosis and if the fix is quite trivial, I'll let them do it, otherwise I'll tow it back. And if it's too expensive to fix, by golly it's going to stay at the dealer

[DarthLowen]

Just thought I'd give you all an update on this, it appears that my initial hunch regarding the rough/no start was the right one (I think this forum even gave me that first clue way before I joined). Fuel lines! the dealer replaced them (I couldn't find them myself???) and now starts promptly! Hopefully my learnings can save someone else a heap of money and/or frustration.

@bgbazz: no VW for me anytime soon

[gazjeep]

Excellent, thanks for posting the solution to help others 

[bgbazz]

Well, I guess you can use your horses to get you home when something goes wrong. 

[XJ Fan]

Well, I guess you can use your horses to get you home when something goes wrong.