Allpar Forums banner

1 - 20 of 23 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter #1
2003 300M 3.5 vin "G", the engine will stall at hwy speeds, PRNDL and odometer displays go out for a few seconds and then come back on with a "no bus" error message. After a few seconds, the odometer comes back on and the "no bus" message goes away. When trying to restart, the starter dosen't seem to stay engaged and will stutter like relay is being turned on and off. Will also act up after a short 10 minute stop after driving. Engine will crank normally sometimes but will also stutter like described above but and will not fire. After 10-15 minute cool down with the hood open the engine will usually start and run fine again. Both issues are intermittent. Trying to find diagnostic info on the web is frustrating at best. Best I can decipher, I may have a crank sensor failing. Anybody have a similar problem?
 

·
Super Moderator
Joined
·
36,916 Posts
I would suspect the crank sensor, except the crank sensor failing would not cause the no bus message.
The no bus message means the computers aren't talking to each other and could be a wiring problem or possibly even a failure (like a bad solder joint) in the instrument cluster.
 

·
Registered
Joined
·
8,042 Posts
Have you had the codes read on it? if not, that should be your first step, just to see if anything comes up.
 

·
Administrator
Joined
·
35,237 Posts
I assumed the no bus condition was the error code.

First thing I'd do is unplug the computer, check for dirt / clean the connections, put on fresh dielectric grease, and reinsert. Actually I'd unplug and reinsert four or five times.

As old relative Joe Stelzer used to say, "90% of failures are just dirt." ;)

(Not really true with modern electrics, which are usually pretty well sealed, but it still happens that dirt and corrosion cause bad connections.)
 

·
Registered
Joined
·
464 Posts
Check for codes... to valuable to ignore, read pending- history. Also some of the higher P1xxx codes may NOT trip cel and those Ucodes are not read by all code readers....

Is there a remote starter? added aftermarket alarm?
 

·
Super Moderator
Joined
·
36,916 Posts
You may also find the car doesn't have any stored codes or that the reader can't pull the codes depending on what exactly is causing the no bus problem.
 

·
Super Moderator
Joined
·
21,351 Posts
U-codes (communication faults) may not be present in the PCM, but can show up in other modules that may require a special code reader/scan tool.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #8
I have Torque Pro on my phone, I used that to scan for codes immediately after the engine stalled but there were no codes present. I will go through and recheck my connections/grounds and wiggle test my harnesses. The PCM connectors are all clean and tight, I'll keep digging.
 

·
Super Moderator
Joined
·
31,981 Posts
People here have mentioned that this problem can be caused by an intermittent connection (solder joint) in the cluster in just the right place.
 

·
Registered
Joined
·
34 Posts
Stick with the basics first. Battery age, condition, connections last cleaned and tightened including the jump post connections. Many electrical gremlins can be cured on LH cars with this simple proceedure first.
Crank sensors have been known to fail without setting codes but the combo of your gremlins points to power/ground distribution.
FWIW if you do change the crank sensor OEM is the way to go. Aftermarket/offshore sensors tend to fail in less than a year...
 

·
Registered
Joined
·
10 Posts
Discussion Starter #11
Went through and checked my power and ground connections, the only thing I found was a slightly loose negative battery cable. I tightened that and started the engine. With the engine running, I went around and tugged on the connectors and moved the harnesses around to see if I had a bad connection or wire somewhere but didn't find anything. I tapped on the cluster too but nothing happened. The problem hasn't occurred in the last couple days of driving so I'm going to replace the crank sensor and just monitor things.
 

·
Registered
Joined
·
464 Posts
recomend you use OEM... aftermarket is too iffy

CATCH 22
When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
 

·
Super Moderator
Joined
·
36,916 Posts
The crank sensor won't cause the no bus message to happen. You've got to look beyond the crank sensor.
 

·
Administrator
Joined
·
35,237 Posts
Agreed, though sooner or later crank sensor will go anyway, so if you plan to keep it for another ten years... ;)

When I see the price of OEM I think aftermarket.
When I see the quality of aftermarket I think OEM.
Absolutely.

At this point, if it was me, I would stop doing things.
 

·
Registered
Joined
·
10 Posts
Discussion Starter #15
Got an oem crank sensor from the dealer, only $38 bucks, not too bad. It even says "made in the USA" on the package. Gonna start with the sensor and see what happens, the "no bus" only happend one time and it was only for a few seconds so I guess I'll have to wait until it starts happening more often to diagnose it.
 

·
Registered
Joined
·
85 Posts
Is there anything else not working on the 300M outside of the engine compartment? I know of 3 Jeeps that had instrument panel codes like that, which was caused by a bad door control module. When the door control module failed, it would cause problems on the bus; simply unplugging it fixed the problem. I agree that loss of the crank sensor would not disturb the bus.
 

·
Registered
Joined
·
8,042 Posts
I'm thinking your "slightly loose" negative battery cable may have been your problem. Loose grounds can drive your PCM crazy!
 

·
Registered
Joined
·
10 Posts
Discussion Starter #18
tlewis said:
Is there anything else not working on the 300M outside of the engine compartment? I know of 3 Jeeps that had instrument panel codes like that, which was caused by a bad door control module. When the door control module failed, it would cause problems on the bus; simply unplugging it fixed the problem. I agree that loss of the crank sensor would not disturb the bus.
I read somewhere that if a crank sensor shorts internally, it can pull the 5v reference low and cause a stall and no bus message. I replaced the sensor a couple weeks ago and so far the problem has not happened again. To answer your first question, the engine is from a 300m, but it's not actually in a 300m anymore....its not even in a Chrysler anymore....



After I built a custom cold air intake:

 

·
Registered
Joined
·
10 Posts
Discussion Starter #19
Update: It has been around 3500 miles since I replaced the crank sensor and haven't had any stalling. Even did a 750 mile round trip to Illinois and back without any issues.
 

·
Registered
Joined
·
8,042 Posts
Sounds like a "mission accomplished" to me. Congratulations and happy motoring. BTW, what is that engine in now if it's not in a Mopar? I have an inquiring mind and would like to know. I'm sure I'm not the only one, either! LOL
 
1 - 20 of 23 Posts
Top