Glock Talk banner

Engine light

1803 Views 33 Replies 20 Participants Last post by  bdcochran
Can a bad alternator cause a check engine light?
  • Like
Reactions: FullClip
21 - 34 of 34 Posts

· Registered
Joined
·
75 Posts
If you pulled the intake go back and double check all vacuum hoses and connections. IME, majority of check engine lights are emission and/or vacuum hoses. You should be able to buy a code reader for less than a box of ammo and you’ll be able to diagnose your own stuff, pick up a service manual off amazon and you’ll be set for the next 100,000 miles. Good Luck, You can do this!
 

· Registered
Joined
·
1,429 Posts
First off, where’d you get the alternator? I’ve heard stories of customers going through 5 or 6 cheap / crap made reman alternators before getting a good one!

And again, your voltage is too low.

***Just saw where you said it was a factory alternator.
 

· Registered
Joined
·
15,934 Posts
Bllorights has it nailed.
1. modern technology (check engine light) has not relieved this old timer of periodic eyeballing the fluid levels, checking for leaks, listening for unusual sounds.
2. an auto parts store, Midas Muffler and my mechanic will run a scan for free.
3. usually, the problem is an unscrewed gas cap or the need to replace the gas cap. have replaced mine twice on a 16 year old car.
4. sometimes, if it is the evaporative system, you can run the car at high speed for an hour and put in a cleaner like Guaranteed to Pass Smog and it works. worked twice this last year. light on again. will try to pass smog. if unsuccessful, run the diagnostics again. option 1 - use a machine to clean the fuel injectors without removing. i have saved some good ones from when i had to replace bad ones about 4 years ago. option 2 - unbolt the catalytic converter and clean it in the sink, but have the mechanic do it. why? Because when i replaced three motor mounts this year, i knew, given the car age, there would be problems, was correct, and a machine shop had to help my mechanic in the effort.
 

· Conservative
Joined
·
291 Posts
Discussion Starter · #26 ·
Replaced alternator, same issue.
Checked for constant drain by using voltmeter between negative battery terminal and negative cable. Shows 11.1 volts !
So IF I'm correct, something is using up all my voltage. Anyone ever use this method of diagnosis?
 

· Registered
Joined
·
5,869 Posts
1st....2006 Honda Accord. 2.4
Back story, 2 days ago I had to pull the intake to replace the starter. It was all good until today when I got the ck engine lite & battery lite. I checked running voltage at 12.2, 11.8 with headlights on. Just bought an alternator and wondering about the ck engine lite being attributed to it.
Car only has 116K on it, I bought it new.
Getting mad at everything going bad. 2 months ago it was an ignition switch.
I consider 15 years and 116k miles a normal time to start having to replace parts. You Honda guys get spoiled when all you have to do is put gas in and do normal maintenance :)

Good luck from someone who drives them until the wheels fall off (20 years and counting).
 

· Native Mainiac
Joined
·
37,863 Posts
Replaced alternator, same issue.
Checked for constant drain by using voltmeter between negative battery terminal and negative cable. Shows 11.1 volts !
So IF I'm correct, something is using up all my voltage. Anyone ever use this method of diagnosis?
If you have a multi-meter that can read amps, put that in line between the negative terminal and ground with the ground cable disconnected and the key off.



Like this video...

 

· Registered
Joined
·
13 Posts
Did you check the connector under the manifold that I told you about? I’ve worked at a Honda dealer for 23 years and I know the cars inside and out. If you leave that disconnected it won’t charge and the light will be on. It charged fine before you took the intake manifold off right? You don’t have a draw you have low voltage because your car is Not charging. check the connector it attaches to the brace that goes from the manifold down to the block. I’ve seen this happen before. It’s gray.
 

· Conservative
Joined
·
291 Posts
Discussion Starter · #30 ·
If you have a multi-meter that can read amps, put that in line between the negative terminal and ground with the ground cable disconnected and the key off.



Like this video...

Did that. It read 0.00.
Just had new alternator checked. They said it's bad! Voltage regulator fails test.
Another new alternator on order.
Maybe, hopefully, this is the issue.
 

· Native Mainiac
Joined
·
37,863 Posts
Did that. It read 0.00.
Just had new alternator checked. They said it's bad! Voltage regulator fails test.
Another new alternator on order.
Maybe, hopefully, this is the issue.
Dang...that bites, but as "The Car Doctor" Ron Ananian says. NEW is short for Never Ever Worked....

Lots of luck...
 

· Conservative
Joined
·
291 Posts
Discussion Starter · #32 ·
Did you check the connector under the manifold that I told you about? I’ve worked at a Honda dealer for 23 years and I know the cars inside and out. If you leave that disconnected it won’t charge and the light will be on. It charged fine before you took the intake manifold off right? You don’t have a draw you have low voltage because your car is Not charging. check the connector it attaches to the brace that goes from the manifold down to the block. I’ve seen this happen before. It’s gray.
FYI to everyone:
RBRK nailed it. The particular connector he referenced was the issue. I had it connected, but not snapped together securely. I grabbed it and squeezed and heard an audible "click".
Fired it up and got 14.4.
So a huge thanks to RBRK.
 

· Registered
Joined
·
15,934 Posts
Update. I finally waited until I failed smog testing to run a smoke test on the lines. Replaced three hoses. Passed. AZmercedes was right. Could be a zillion things, usually related to the smog. Happy that I didn't have to go beyond what used to be called an Italian tuneup plus shoving chemicals in the gas tank to burn out carbon deposits.

My state rules are simple. If you don't pass smog and don't own a historic vehicle. there is no limit on what you must pay to pass smog. Missed a bullet this time.
 
21 - 34 of 34 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top