I hope that you won't be too upset seeing another post about the dreaded Service Rear Axle message?
I've tried every suggestion I came across reading through the posts on the subject, so far nothing has worked. I replaced the battery approximately 2 years ago, It was fully charged, I tested the voltage, the local dealer repair department didn't find any mechanical issues, there was some corrosion on two of the wire harness clips, and an intermittent short at the battery cable connectors which they replaced. I have disconnected and reconnected the battery cable, a number of times to no avail. The message will clear when I press the "SEL" button on the steering wheel, but it returns again after it's been parked and I drive a few miles.

Can this be an alternator issue? No problem starting, no stalling, no screeching sounds, no burning rubber smell,, no CEL.

Any suggestions?

Thanks !

 

What is the battery voltage with engine off? Should be near 12.6 v. Weak battery / low starting voltage tends to cause comm errors.

Monitor the voltage when the engine is running - charging voltage 15.5+ is usually a bad alternator.

Use the digital TOUR display to best see the voltages.

Ron

 

Thanks Ron!

I followed your suggestion, the voltage sits at 8, with the engine running at 14. I don't drive as much now, health stuff, so I use a trickle charger when my car sits a while undriven, it was on the charger before I checked the voltage as you suggested.
Any thoughts?

Again, thank you!

 

8 v is way too low. Bad cell in your battery.

14v is a reasonable charging voltage - no obvious alternator issue.

New battery time.

Ron

 

It’s the small gauge black wire at the battery. Sorry to repeat but I preach this regularly. Doesn’t matter if it looks or feels solid. The internal conductors of the wire break or there is resistance. Cut the wire back a couple inches and solder a new connector. Problem will be gone. This often happens when battery is changed and the wire is disturbed.

 

If you don't have any battery test equipment go to an Auto Zone store and they will hook their equip up and test out the complete battery system. Battery, alternator, charging voltage engine running and off, with and with out electrical loads.

All they have to do is to be able to connect directly to the battery posts so I would advise you to pull back the carpet before going to the store.

 

I am a bit new here. Just so that I understand. You get a "Service Rear Axle" msg, then you service the rear axle, and the msg doesn't go away?

 

No, what we're saying is that a weak battery / low voltage on engine start can cause network comm errors - commonly triggering a false "service rear axle" message. Weak / old batteries are known to cause all kinds of electrical gremlins on these rolling computer networks called Corvette.

Ron

 

Thanks Ron!
I replaced the battery approximately 2 years ago, I don't drive my car very much, when I replaced the battery I fully charged it. I use a trickle charger when leave my car undriven for a while. But you're right, 8 volts is way too low!

 

Thanks for responding!
When I took my C7 to the local dealer, they found intermittent shorts at the battery, as a result the cable connectors, including the small black wire were replaced.

 

Thanks for responding !

I used the display in touring mode that shows the list of temperatures, tire pressure, and battery voltage, the indicators showed 8 volts not running and 14 volts with the engine running. Are you suggesting that the battery system test at AutoZone would give a more complete answer?

Thanks again!

 

8 volts not running is not good. It should be 12+ not running.

 

I have read all your posts on the "service rear axle" msg and the battery issue that you have. I agree this doesn't make much sense. When you said the dealer checked the mechanical issues, they for sure, checked the fluid level?

 

I bought a battery load tester, it checks the battery condition, with and without a load, as well as the alternator.
So far, I tested the battery, without a load it shows a little more than 12 volts, under a load the voltage drops to 10 1/2.
I'll test the ignition when I can get a little help, need someone to press the start button while I'm looking at the voltage.
Stay Tuned, and thanks for your help!

 

Yep, they certainly did check for proper fluid level, thanks!

 

I want to be sure that it's clear, I used the cars onboard computer to check the voltage. I picked-up a battery load tester, it indicates 12.5 volts without a load, and 10.5 volts with a load, When I have some help I can test the voltage at ignition, that should provide more information, hopefully?
Thanks!

 

I picked up a battery load tester this afternoon, without a load it reads 12.5 volts, with a load 10.5 volts.

In order to test the voltage during ignition, I'll need someone to press the start button while I check the reading on the tester, later.

Thanks !

 

Service rear axle message 99.7 % of the time is the result of another failure . You will get it if u have low voltage , one of your critical modules did not boot up ,and a million other reasons , this is why it's so hard to pinpoint the cause .

The ECM or BCM detects a fault and will start shutting down systems like the rear axle module , anti lock brakes etc . If the fault is critical, it will even put the car in low power mode .

1st test would be checking for codes , both active and in history to see if there is a problem that is causing the system to shut down . You need a good scanner to access ALL the modules on a corvette as the 20.00 Amazon scanners and some Bluetooth do not

Since the OP stated he has 8 volts with engine off , not sure how he is measuring that , I would suggest that he leave car untouched overnight and measure resting battery voltage in the AM with a multi meter. Voltage should be 12.6 for a full charged battery , and nothing below 12.3 is acceptable after resting overnight

12.3 , really needs a charge and a test again the next day , If its back at 12.3 the next day , at that point you will need to measure parasitic draw , if the draw is within acceptable range then i would replace the battery,
Battery tests done at auto parts houses are questionable at best and most people chase their tails because the test said their battery was good

Good luck finding the cause and let us know the outcome

Dave

 

I suggested AutoZone because almost all people don't have any real test equip at all.

I picked up my test equip over the years, when talking about test equip good and cheap usually don't go together. Good test equip = $$$$

AutoZone is the cheapest way to go, but not always the best. You get what you paid for.

Good luck.

 

Thanks for your helpful response!

In Tour mode I looked through the list of things that the onboard computer stores such as, tire pressure, gas mileage, oil life, battery condition.

I also purchased a battery load tester, that indicated 12.5 volts without a load, and 10.1 volts with a load, from what I read, if the reading is lower than 9 volts with a load, it usually means the battery is weak. I'll test again with the engine running to see if the alternator is working properly.