dslpwr

This morning on the way to work the voltage gauge bottomed out on the left and the check gauges light came on. I pulled the code and it was for low alternator voltage when i got home and checked with my multi meter at the battery and it was charging at like 17 volts. So i went and bought a new alternator, installed it and it's still charging at 15+ volts. I've read that it could be the voltage regulator in the pcm? I know the battery is good and the alternator is new obviously. So what are your thoughts on it?

prcherokee

Check your battery temperature sensor.

dslpwr

How do I check that? I can run my meter over the plug but what am I looking for? Like ohms or whatever

dslpwr

I found its supposed to be between 9 and 11k. I'll check it here after a bit.

dslpwr

Ok so after new alternator and refreshed all the grounds The voltmeter isn't registering anything but it is still cranking out 15+ volts. My conclusion is the voltage regulator went south if it's not reading anything on the dash but still cranking out a charge. When I pulled it into the garage the voltmeter read a normal 14 or so volts for a minute then bottomed out again.

Turbo X_J

"I pulled the code and it was for low alternator voltage when i got home and checked with my multi meter at the battery and it was charging at like 17 volts. So i went and bought a new alternator,"

Sounds like a wiring issue, what was the code number exactly?

dslpwr

Iirc it was 1682. Charging system voltage to low.

Turbo X_J

Try hooking up your DMM across the battery terminals while the engine is running and wiggle the connectors at the PCM. Watch the meter and see if there is any change. What happened with the BTS?

dslpwr

It was like 17.26on the 20k setting so not in the normal parameters. I'll try wiggling the connectors here and see what happens on the meter. But i suppose I'll hafta grab a sensor tomorrow

dslpwr

Would the temp sensor really have that much to do with it?

prcherokee

Did you check it at room Temperature?
(2) Disconnect the two-wire pigtail harness from
the engine harness.
(3) Attach ohmmeter leads to the wire terminals of
the pigtail harness.
(4) At room temperature of 25° C (75–80° F), an
ohmmeter reading of 9,000 (9K) to 11,000 (11K) ohms
should be observed.
(5) If reading is above or below the specification,
replace the sensor.

dslpwr

Yeah its been in my garage at 65 degrees for 2 days so it's plenty warm. So I got it running now with the meter on it and messing with the pcm cables. Nothing out of the ordinary. I had discharged the battery after it was overcharged by the alternator had to jump start it. With the meter on the battery posts it was charging up from 9.2 volts to just about 10 when it died and now threw the code 1492 "battery sensor input voltage too high" which I never had before. The sensor ohm'd at 17 and some change so I'll pick one up tomorrow and see what happens

prcherokee

I believe if you lose ground to the sensor (& through the PCM) you get P1492.

Turbo X_J

Lets back up a little bit, how do you know the battery is good, was it load tested?

dslpwr

Yeah it was load tested and deemed ok. I'll bring it with tomorrow when I go to the parts store and have it done again just for grins though. It's only a little over a yr old too.