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Cat warning light

Posted: Fri Dec 20, 2019 12:25 pm
by Sailor
Driving the Integra home in pouring rain yesterday, the cat and battery warning lights came on at the same time. The CEL did not show.

I drove about 3 miles to where I could safely park and waited 5 minutes. Switch on again = no warnings, but they reappeared a minute later and went on and off for the 5 miles home.

This morning, nothing. I drove around to get the car up to temperature. Still no lights. No CEL codes either.


It's a new one to me. We're supposed to be going to Germany the day after tomorrow; the Volvo has a broken tailgate window and I don't want to take the Accord (it doesn't seem all that reliable at the moment.)


Ho hum.

Cat warning light

Posted: Fri Dec 20, 2019 12:28 pm
by RattyMcClelland
That will be the alternator. Usually intermittent cat/battery light is irregular voltage from a potentially failing alternator.

Cat warning light

Posted: Fri Dec 20, 2019 12:43 pm
by Vtecmec
I'll second rattys comments.....

Cat warning light

Posted: Fri Dec 20, 2019 1:13 pm
by Scott560
If the weather was very bad - it might have just been a bit of water ingress, or perhaps a bit of belt slippage? With this weather and cold conditions, alternator gets a bit harder to turn...

Liberal dose of WD40 all over and check the voltage at idle, if its all good its probably just a bit of water messing with the regulator connections...

Cat warning light

Posted: Fri Dec 20, 2019 2:58 pm
by vanzep
Also check the crank pulley is ok/not loose/wobble etc ;)
prob as others have said alt on its way out or just bit belt slip

Cat warning light

Posted: Fri Dec 20, 2019 10:49 pm
by Sailor
RattyMcClelland wrote:
Fri Dec 20, 2019 12:28 pm
That will be the alternator. Usually intermittent cat/battery light is irregular voltage from a potentially failing alternator.
I wondered about that.
I was hoping I'm wrong ...

Cat warning light

Posted: Sat Dec 21, 2019 7:30 pm
by Sailor
And so it is: the alternator (or its wiring) is playing up.

I put the meter on it this morning. No warning lights and charging at 14.7v. Luvverly.
Out this afternoon, the warnings reappear. Measure again: barely 12v.

Something to look forward to when we get back from Deutschland ...

Cat warning light

Posted: Thu Sep 10, 2020 6:27 pm
by Sailor
Sorry. I forgot to say what happened in the end.
You all got it right! [Alternator]