christitan

I'm hoping someone can offer a solution to the problems I'm having with my 2000 Lexus RX300 AWD. It started about a week ago with the battery light intermittently coming on. It wasn't long before the check engine light came on with a code for a mass airflow sensor. I figured this was probably due to the electrical system because I have had other vehicles throw some unrelated related codes before when having problems with the electrical system.

My wife was taking my son to the zoo yesterday when the electrical system totally went down while on the highway. She said that it started with the radio getting fuzzy. When she tried to switch the station she noticed that every station was fuzzy. Next, the check engine light and dash lights started to fade out together. This lasted for a moment or two before all of the electrical components went dark. Said that this lasted for 15 seconds (which I believe is probably more like 5 seconds) and then everything came back on.

I drove down to swap cars with her so she could continue on. While driving back to work I only experienced the battery light and check engine lights, but no complete failure. I took the RX to AutoZone to have the codes checked again and the problems seemed to all be electrical component failures.

Last night I checked the following connections

• ground wire from the engine block to the battery
• all connections to the alternator
• positive battery connection

In addition to checking to make sure that all of these connections were tight, I also cleaned them with electrical contact cleaner. I also cleaned the battery terminals and connectors with a wire brush.

I reset the check engine light by pulling the ECT fuse and then I went for a drive around the neighborhood. I didn't have any lights come on or experience any power failure while cruising my sub-division.

My wife called again today and told me that the battery light came on when she first started the car. She shut it off and back on and the light went away. She said that the clock keeps setting to 1:00 and the car does not hold her power seat positions.

I replaced the battery a year or two ago and the alternator three years ago. This seems to me like a loose ground, but after checking the connections I cannot find anything that is loose. Any ideas?

Thank you in advance,

Chris

thomas1

Your battery could still be the culprit, there may be a intermittant cell inthe battery...If you have a voltmeter check and see if you are getting 13.5 to 14.5 volts on the terminals while the engine is running...if not the battery is bad or the alternator is going bad.

salimshah

Your battery is not getting charged by the alternator. Without the charge, every thing is running of the battery. As the battery starts discharging the sensors and ecu starts getting bad data and you get CEL.

Once my belt broke and it took 35min of driving before the whole system shutdown on me.

Now the question is why is the battery not getting charged (battery light). Check the belt. Check the battery (take it to a shop and they can test it). Have the charging system (alternator) tested. Best test is when the alternator is out the test bench but it can be tested in the vehicle. Remember to turn on all the loads (lights, brakes etc).

Last of all there can be a bad load which can cause problems. I would suggest removing the fuse or wire of any add on (non-factory) accessory ... remote starter, amps etc.


Word of advice for all .. Always start with the first indicator of the problem. In this case it is the battery discharge warning lamp.

Salim

christitan

Thank you both for your replies! We don't have any aftermarket accessories attached to the car or even a trailer hitch for that matter. I really have my doubts about the problem being with the alternator because we have been driving it for about a week since the symptoms started. I drove a 1995 Toyota Corolla from Kingman, AZ to Redlands, CA with a bad alternator on a fully charged battery (needless to say I didn't have enough power to run a dome light by the time I got there). We haven't had any trouble starting the car throughout all of this. An intermittent cell may be the answer though. Thanks again for your insight!

-Chris

christitan

thomas1,

I checked the voltage both at the battery and at the alternator. I have exactly 13.5 coming out of the alternator, and 13.2 at the battery. Is this normal or on the low side?

-Chris

thomas1

Was that with the headlights on to give it some load? The voltage sounds fine...I would be looking at a new battery...suggest Walmart or Costco, or Sams Club.

bufferdan

Have another car that you can swap batteries with?

christitan

Well, my failing electrical system came to a head today. My wife called from the eye doctor and said her car wouldn't start. When I arrived I put the multimeter on the alternator and was only getting 6.2 volts coming out - bad alternator. Wouldn't you know it a black cloud rolled in over top of us. Luckilly I was able to make it to our church and pull in under the overhang to swap the alternator. Just the other day she was experiencing problems in a really bad part of town on her way to the zoo. God was surely looking out for us! After swapping the alternator she is back on the road!

I have never experienced intermittent problems with an alternator before it dies. I thought that when a diode burns out it was always a sudden malfuction, but I guess not. Thanks to all who offered suggestions; they led me to pickup a multimeter to help diagnose the problem.

salimshah

Which did you choose .. reman, or new. OEM?



Salim

thomas1

Did you get the alternator at OReillys? (Kragens) I have had absolutely the worst luck with their parts...5 alternators on a Ford Ranger...I never buy remans from them...Glad you found the problem.

sktn77a

iTrader: (2)

Usually yes, but it could have been something other than the diode.

code58

Thomas, where DO you buy rebuilts that are consistently good? I simply don't like rebuilts, anyones rebuilts. My brother got 4 alternators for his son's Mercury (whatever is equivalent to a Ford Escort) before he got a good one. I bought a rebuilt for my son's Camaro years ago (car only had about 30k mi on it) and having such bad luck with rebuilts, decided to pull it apart before I even put it on to save having to pull it back off. When I opened the case, one of the 3 leads that go from the field to the diode trio (same stud) was ripped right off! I appears they used an impact to spin them on and that nut caught the wire with friction and ripped it right off! I believe the problem is too many people who are robots (don't speak or understand English) but will do repetitive lobs for low pay, having little if any idea what they are actually doing (hence the term robot), as well as too many CHEAP parts from 3rd world countries that have little chance of lasting till your next B'day, no matter when it is! My boss (now retired, but when I was working) gave me an alternator off his Corvette that he had purchased from Napa only 13 mo. before. Didn't even have dust on it. He bought from Napa because they were supposed to be good. You don't have to wonder why I buy quality name brand parts and rebuild my own, the REBUILT route is simply ridiculous.

salimshah

My choices are:

Rebuild myself if possible
or
OEM .. specially if the original gave good service. I do price the re-manufactured and then say ... look how much money I saved by doing the labor myself and most of the time, I am ahead.


Let's see what Thomas has to say.

Salim

christitan

I had already replaced the alternator once so I had a lifetime warranty through AutoZone. My guess is probably a cracked solder joint or something. It wasn't worth it for me to tear it apart and find out for sure. The new one is a rebuilt, I figure if it goes out again i will just do the warranty thing once more. nothing like fixing the car at no cost!

-Chris

thomas1

agreed Roger, I try to rebuild myself, Napa used to be good, lot better than Kragens or Oreilly....I rebuild my own alternators with oe bearings and brushes...works fine and last extremely long time.