Jmeyer152

I have a 2007 tech package with ~110Kmi. My wife drives it daily and has been perfectly fine the 7 years we've had it.

This morning as she started up she got both:
Check SH-AWD System
Check Charging System warnings

She then put it in drive and hit the gas and the car started jumping. She explained that it was acting as if it was in neutral, she hit the gas, engine revs, then thrown into drive.
She immediately got off the gas and coasted back into the driveway.

She called the local dealership asking if it was a common issue, and obviously got a "I dunno" in response.

Anyone experience, or know what this could be?!

Tomtwtwtw

Just going by the messages I would check the alternator and/or battery. My theory would be that the alternator is still generating power, but only just a trickle. Otherwise your car would likely die shortly after starting once the battery itself runs out of juice. A low battery voltage can give you transmission problems, and it's possible that revving the car got the alternator going enough to shift into D.

The battery is cheapest option, and an alternator will probably run a hundred or so (if you can DIY), otherwise from my experience with other cars it is usually a 300-500 dollar job. Unfortunately I have no idea how much it typically runs on an RDX.

mrgold35

My alternator just went out about 2 months ago in my 08 RDX with 105,000 miles. We got some early warning with the "check charging system" and "Check sh-awd". Took it to the dealership and they said everything is fine and you need a new battery for $200. I told them no because I have a new interstate battery still within its free replacement time.

Interstate tested the battery and said it was 100%. I was going to take it back to Acura in the morning and it did the same thing as your vehicle. It would not start at first; but, I was able to get it started after it sat for a while. Drove it back to Acura and then they said my alternator wasn't putting out enough volts and it was draining the battery when driving. They wanted to charge me $600 to replace. I looked locally and found an alternator and a shop to replace for $280. She has been running fine ever since.

Jmeyer152

Thank you for your quick replies and it did seem to make sense. Unfortunately, I had a little communication issue on my end with my wife, that had one detail left out... The car actually ran just fine for a couple minutes. She got out to the major road. And the "Neutral Drop" like symptoms started after trying to pull out onto a busy road from a complete stop. So, the car had the alarms upon start-up but successfully got into Reverse to get out of the driveway and into Drive to go down the street. Then started with the Stuttering and she limped the car back home.

Tomtwtwtw

That is somewhat in line with an alternator that is about dead and a car running on battery alone. Way back when, I replaced what I thought was a dead battery and drove without issue for 3 days, when in fact it was my alternator that was out. I found out the hard way - as I was driving my radio started getting lots of static, my transmission got stuck in 2nd gear, and in the last few seconds all of my dash lights flickered and the car just died out.

If you have a way of charging the battery, try that first, or maybe just drop in a new one if you current battery has a couple years on it. Either way with a full battery I bet the car will run great. Might still have the SH-AWD and Charging System lights on if the alternator is bad, but either way the car should run fine for a while on battery alone. Good luck.

dcmodels

Alternator output, while the engine is running, can be checked with an inexpensive digital voltmeter that plugs into the accessory port. If the alternator output is too low, then the alternator can be checked further or replaced. Or any local auto parts store can check it for you.

The BATTERY / CHARGE indicator on the RDX dash INSTRUMENT PANEL is supposed to light (display) if the alternator is not generating correctly, but sometimes it does not work correctly.

TEST EQUIPMENT – EVERSTART BATTERY MONITOR VOLTMETER p/n 932W:
This inexpensive digital device measures between 8.0 and 19.9 volts DC. It displays only to a single decimal point. It draws 0.1 amps because it has 3-LEDs and the 3-digit display. The device was purchased from Wal-Mart.

This device is useful in indicating any problems with the vehicle charging system, e.g., the alternator. For example, the RDX voltage should read between 13.5v and 15.1v when the engine is running. The device can be plugged directly into one of the (cigarette-lighter type) charging ports on the dash, which will give a reading only when the engine is running. The ports are not *live* unless the key is in the RUN position.

This voltage-meter device can also be used as an alternative to a battery Load-Test, by verifying that the battery voltage is between 9.5-10 volts (minimum) during an engine start.

You may find the following link helpful:
how to care for the battery:
https://acurazine.com/forums/showthread.php?t=775689


---eof

Jmeyer152

We changed out the alternator today and the problem is SOLVED!

Thanks again to all of you!

Raisuroketto

I just had the exact same problem... after 99,200 miles!

My 2007 RDX has been running without any problems whatsoever until now. Suddenly and without any prior warnings I got the exact same warning lights that Jmeyer152 reported:

Check SH-AWD System
Check Charging System warnings

When I put in in drive it wouldn't move. I pressed the accelerator a bit more and with a jerk it lunged forward. It sounded like the gear suddenly popped in. Extremely unnerving! I turned off the car. It would not start again. It wouldn't even turn the starter. After first freaking out, thinking it was some weird and huge electrical problem or that the AWD was shot, I calmed down and read the posts here. I became convinced it had to be battery or alternator, hoping for the former but my gut told me alternator.

ESSENTIAL TOOLS:

- Multimeter
- Battery charger

TROUBLESHOOTING STEPS:

1. Checked the battery with a multimeter... less than 12V (not good!)
2. Charged the battery overnight... took a whopping 18 hours to fully charge (with a brand new good charger)!!
3. Checked the battery again with multimeter... 14.2V (great!)
Comment: Thanks dcmodels for the 13.5-15.1 V guideline! That is very useful information when troubleshooting!!
4. Tried to start and she started right up without any warnings or problems... Check!
5. Checked with the multimeter while the she was running... voltage dropped instantly to 12.8V instantly (not good!)
6. With the engine still running, I placed the charging system under load; turning on hi beams, radio, A/C, everything and everything.
7. Check again with the multimeter... voltage dropped to 12.08V and kept dropping.
8. At this point I became fairly convinced it was the alternator not charging sufficiently.
9. Turned off hi beams, radio, A/C, and Nav.
10. Voltage went back to 12.8V and hovered around that level.
11. Since the battery charge went up without a lesser load I became even more convinced it was alternator.
12. Drove to the closest auto parts store that offered a free battery and alternator check. They did it free of charge, which many good auto parts stores will.
13. Results:
Battery = good. They gave me a nice printout of voltage, cold cranking amps, and temperature. Great condition!
Starter = normal!
Alternator = bad. It even spelled out how it was charging under no load (12.87V) versus load (12.04V).

At this point, the RDX is drivable but probably not during night time. I am replacing the alternator tomorrow.

I am definitely buying the Everstart Battery Monitor Voltmeter that dcmodels recommended!

Keep in mind that these alternators, for some odd reasons, seem very hard to find. I had to search auto parts stores all over the San Francisco Bay Area and finally found one store within a 50 mile radius that had one in stock!! I am charging the battery overnight to make sure I have enough "juice" to get there tomorrow.

dcmodels

Glad that you found your problem - your procedure was reasoned and logical.

Just to clarify for others reading this thread - the 13.5-15.1v specification is for the output of the alternator with the engine running, not the voltage level of a fully charged battery. Based on the steps above, that 14.2v that you read, was *before* the engine was started, and just after charging the battery.

The 14.2volts is a surface charge, and not indicative of a good battery, as even a bad battery can show a high surface charge, and still not actually hold the charge during an engine start-attempt.

A battery charger will typically charge at 14.4 volts, and will provide a maintenance voltage level of 13.4volts, if it is one of the new electronic *smart* chargers.

The only valid battery charge level reading can be taken after either: the battery has sat without any load for 12 hours after removing the charger, or after starting the car and then allowing the battery to sit for another 4 hours minimum. Either procedure will remove the surface charge from a newly charged battery.

A fully charged battery will read around 12.65volts. A reading of only 12.00 volts means the battery is holding only about 25% of a full charge. Yes, its supposedly a 12 volt battery, but that is merely a nominal rating.

More about this can be found at the link in my post above about battery care.

Skyyler Scott

The exact same thing happened to my 07 Acura RDX. We found out it was the alternator, we went and bought one from the auto parts store. But eventually the problem came back. We had to replace to alternator with a newly build alternator and the problem was fixed. The rebuilt alternators don't hold the correct amperage. You'll need to take it in and have them replace it with a band new one from the Acura dealership. I'd also replace the battery