Service Charging System Error and Instrument Cluster Intermittent

[dj lpm]

All -

Just started getting an intermittent "Service Charging System" error, followed by the Instrument Cluster going completely out (gauges stop working, lights off, everything) and then coming back on again randomly.

Its happened like 4 times in the past two weeks, and by the morning, it seems to be ok.

It seems like it might be a loose connection, but have no idea where to start. Fuses look good.

Thoughts?

DJ LPM

[Napalm]

loose or corroded connections between the dash and he BCM.

Faulty BCM - that has another set of codes though and you'd have to have a real code scanner that sees all systems on the car (Tech 2 - some other alternatives - I use OBDLink with ScantoolXL software)

And you might well have weak voltage while running. Either the alternator doesn't put out enough or just a bad battery.

First thing I might try is a new battery - just on general principle. Everything is tied there so if it flakes out - has high resistance - or something - then it can cause the computers to get weak power even if the alternator is putting out good juice.

5 step test.

Multimeter on DC volts - check battery with car off - just straight test.
Multimeter on DC volts - start car - let run for a minute - headlights on - AC on or radio on. - test volts at the battery terminals. Should read between 12.8 and 15 V DC. Yes it's a range and yes it can crest 15V. The alternator is a variable field effect/variable output device.
Test the battery ends - then test the battery cables - to insure there is a good connection and power pass though
Multimeter on AC volts - same conditions as before - check battery terminals - should be under 1 VAC. Caution - most multimeters run an RMS average for AC volts - so it might start at say 5 - and quickly drop to 2 then 1 then 0.something. This is fine. If after 20 seconds it stays above 1VAC - then you probably have a bad alternator and that AC voltage is killing or has killed your battery.

Good luck and keep us posted.

[dj lpm]

Thanks Napalm. I will definitely run your diag recommendation.

I also noticed in engineering mode that voltage after warm up was running between 15-16 volts at times. Seems hot but I don't know how reliable the onboard sensor is.

Can you also send me a link to the OBDLink with ScantoolXL product? I thought it was this but not sure.

Thanks,

DJ LPM

[Napalm]

I bought this because it was the cheapest scan tool setup that supposed would read SRS (airbag) codes on our car. And it does.

https://www.scantool.net/obdlink-mxbt/

You can buy other cheaper BT links - I don't want to risk shorts or other issues on a 5 dollar knock off so I like this BT unit.

you can buy this from other places slightly cheaper but no software - this place sells both at a discount so for 260 or so all in I got the tool, and the software for windows at the same time.

It does read SRS, ABS, Body systems, and ECU/TCU - it's everything on the car that I can think of. There's a touch of a learning curve but it isn't much.

I got the BT version because I also use it with my phone and I use the torque pro app with add ons on android. also cheap. SO I occasionally log veichle data with that.


For example when my alternator died in July - I used torque pro to watch what it did before the dash light would come back on. Oh and like I said it's a variable output device - I think at max it can hit 16 volts but that sets a fault I believe. Reasoning - it should never need to provide that much. But I have on weak battery seen it spike to 15 for a few minutes after startup - then drop down.

How old and what is your battery - I think you might have a battery issue.