2002 P5 Battery Light

[manos]

OK my battery light has been on for the past 2 months. Every time I take it into the shop they say the battery is fully charged and the alternator is fine. Battery is 1.5 years old anf alternator is less than a year old.

Issue started after my 60K service when they changed the belts.

Going to plug in the diagnostics box I borrowed from my boss this evening and see what it says. Any idea where I can DL the DTC codes for the P5?

 

[i12drivemyMP5]

Just google obdii dtc codes, you'll find the list.

 

[manos]

alrighty, battery light still coming on intermittently. No engine code.

New Battery 2 years ago, new alternator 18 months ago.

 

[jeg0024]

Take the gauge cluster out and remove the bulb for the battery light. Problem solved!

 

[DH Motorsports]

There must be an issue yet with the charging system. The ECU doesn't turn it on just for the heck of it. Perhaps its overcharging your battery or something else...

Bottom line- its not normal, don't just accept it. Find out whats going on.

 

[pasadena_commut]

There must be an issue yet with the charging system. The ECU doesn't turn it on just for the heck of it. Perhaps its overcharging your battery or something else...

Exactly. Keep a voltmeter in the car and next time the light comes on pull over, pop the hood, and check the voltage on the battery. (Don't have a voltmeter? Buy one, they are cheap and absolutely essential for diagnosing electrical problems.) My bet is that when the light is on the voltage will be out of range.

Intermittent problems are notorious for not putting in an appearance when the car is in the shop.

 

[25FConv]

Hey check your (IAT) Intake Air Temp Sensor. When Mine wasn't plugged in my battery light was on. When I corrected the situation the light was gone. Your would think neither has anything to do with each other. I came across a post from Ken at protegegarage.com pu ton here and I tried it out and that was the issue. Maye the connection is faulty. Give it a shot and check if everything it hooked in properly.

 

[i12drivemyMP5]

Weird science..........

 

[manos]

Voltmeter in the car. just checking, I check the voltage from terminal to terminal, terminal to ground?

Intake Air Sensor, will need to see if I can find that.

 

[P-Funk!]

Measure at the battery pos and neg.