Define "low voltage"
Thread Starter
Pro
Joined: Feb 2005
Posts: 564
Likes: 1
From: Saint George Utah
Define "low voltage"
I've been having a few intermittant electrical issues such as the ABS/traction control light coming on twice and the remote not opening the doors. Car is a daily driver 2000 with 105,000 miles. Battery is just a few years old.
I recall reading a thread where it was suggested to a member that his difficulties (don't recall what they were) may be a result of low voltage. Seems to me I used to see 14-14.2V on the DIC but noticed today, with AC on max output (105 degrees outside), that the voltage was in the 13.2-13.4 range.
Am I suffering from low voltage? Is my alternator on the way to the graveyard? Or is the voltage lower than usual because the AC is on and the fan is on max output?
I recall reading a thread where it was suggested to a member that his difficulties (don't recall what they were) may be a result of low voltage. Seems to me I used to see 14-14.2V on the DIC but noticed today, with AC on max output (105 degrees outside), that the voltage was in the 13.2-13.4 range.
Am I suffering from low voltage? Is my alternator on the way to the graveyard? Or is the voltage lower than usual because the AC is on and the fan is on max output?
Tech Contributor
Joined: Jan 2007
Posts: 19,293
Likes: 1,110
From: Dyer, IN
I've been having a few intermittant electrical issues such as the ABS/traction control light coming on twice and the remote not opening the doors. Car is a daily driver 2000 with 105,000 miles. Battery is just a few years old.
I recall reading a thread where it was suggested to a member that his difficulties (don't recall what they were) may be a result of low voltage. Seems to me I used to see 14-14.2V on the DIC but noticed today, with AC on max output (105 degrees outside), that the voltage was in the 13.2-13.4 range.
Am I suffering from low voltage? Is my alternator on the way to the graveyard? Or is the voltage lower than usual because the AC is on and the fan is on max output?
I recall reading a thread where it was suggested to a member that his difficulties (don't recall what they were) may be a result of low voltage. Seems to me I used to see 14-14.2V on the DIC but noticed today, with AC on max output (105 degrees outside), that the voltage was in the 13.2-13.4 range.
Am I suffering from low voltage? Is my alternator on the way to the graveyard? Or is the voltage lower than usual because the AC is on and the fan is on max output?
Post Your Codes
Instructor
Joined: Sep 2010
Posts: 117
Likes: 0
From: Michigan
The DIC does not give actual battery voltage, it basically gives charging information. To know real battery voltage you need to check at the battery with a voltage meter.
"8vette7" told us that you need more than 12.5 volts at the battery to make all the little electrical gadgets work, yet the car will start and run at something like 12.2. Silly isn't it!
"8vette7" told us that you need more than 12.5 volts at the battery to make all the little electrical gadgets work, yet the car will start and run at something like 12.2. Silly isn't it!
Thread Starter
Pro
Joined: Feb 2005
Posts: 564
Likes: 1
From: Saint George Utah
Before starting this morning the DIC was reading 12.2V. After starting it went to 14.4V. That seems more normal than what I was seeing yesterday. But 12.2V is too low?
I'll grab the codes and post them.
I'll grab the codes and post them.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
BATTERY VOLTAGE!
The voltage reading on the DIC (Digital Reading in the DIC) and the IPC Meter (Analog Gage) is NOT the actual battery voltage! Those meters reads the voltage supplied to the modules on the HOT in RUN and Start buss. That voltage is supplied by the IGNITION SWITCH.
IF,,,,,,,,,,,,,,,,,,,,,,,,,, the ignition switch contacts are dirty, carboned up or BURNT,,, the voltage out of the ignition switch can be LESS than the actual battery voltage measured directly at the battery..
Most all of the modules in the car have duel power supplies. One is the HOT AT ALL TIMES that is supplied directly by the battery and the other is HOT in RUN and Start or HOT IN RUN AND ACC.
You can measure the actual battery voltage at the battery OR at the CIGAR Lighter outlet.
The ALTERNATOR output voltage depends on several factors. Battery charge condition, temp, and circuit load. When the actual alternator output is 13.XX when the engine is running,, it is not necessarily an indicator of trouble.
The alternator charges the battery from the output terminal ( BATT Terminal ) on the on the back of the alternator (under the black rubber boot) and it goes down to the starter solenoid and from there to the battery POS terminal.
IF,,,, the connections on the back of the alternator and or at the starter solenoid are loose/corroded/damaged or burnt,, it will cause very sporadic and insufficient battery charging voltages. MAKE SURE that the starter solenoid connections, battery terminals and the alternator output terminal are in good shape and tight and clean.
The other area of electrical trouble is chassis ground G-104/108. Follow the SMALL BLACK GROUND WIRE on the battery negative terminal down to the chassis ground stud on the frame next to the battery and make sure that the connection is clean and tight!
What is the battery voltage reading directly at the battery terminals???
Engine OFF=
Engine Running=
UNDER FULL LOAD =
Measure the battery output when the engine is being cranked. Best time to observe this reading is when the engine is COLD. Have someone crank the engine while you read the battery output before and during cranking. If the battery is good, you should NOT see it drop below 10.5 - 11.00
I’ve see old batteries that still start the engine drop as low as EIGHT VOLTS during cranking. When that happens all sorts of crazy electrical stuff happens and all sorts of weird DTCs show up after cranking.
BC
The voltage reading on the DIC (Digital Reading in the DIC) and the IPC Meter (Analog Gage) is NOT the actual battery voltage! Those meters reads the voltage supplied to the modules on the HOT in RUN and Start buss. That voltage is supplied by the IGNITION SWITCH.
IF,,,,,,,,,,,,,,,,,,,,,,,,,, the ignition switch contacts are dirty, carboned up or BURNT,,, the voltage out of the ignition switch can be LESS than the actual battery voltage measured directly at the battery..
Most all of the modules in the car have duel power supplies. One is the HOT AT ALL TIMES that is supplied directly by the battery and the other is HOT in RUN and Start or HOT IN RUN AND ACC.
You can measure the actual battery voltage at the battery OR at the CIGAR Lighter outlet.
The ALTERNATOR output voltage depends on several factors. Battery charge condition, temp, and circuit load. When the actual alternator output is 13.XX when the engine is running,, it is not necessarily an indicator of trouble.
The alternator charges the battery from the output terminal ( BATT Terminal ) on the on the back of the alternator (under the black rubber boot) and it goes down to the starter solenoid and from there to the battery POS terminal.
IF,,,, the connections on the back of the alternator and or at the starter solenoid are loose/corroded/damaged or burnt,, it will cause very sporadic and insufficient battery charging voltages. MAKE SURE that the starter solenoid connections, battery terminals and the alternator output terminal are in good shape and tight and clean.
The other area of electrical trouble is chassis ground G-104/108. Follow the SMALL BLACK GROUND WIRE on the battery negative terminal down to the chassis ground stud on the frame next to the battery and make sure that the connection is clean and tight!
What is the battery voltage reading directly at the battery terminals???
Engine OFF=
Engine Running=
UNDER FULL LOAD =
Measure the battery output when the engine is being cranked. Best time to observe this reading is when the engine is COLD. Have someone crank the engine while you read the battery output before and during cranking. If the battery is good, you should NOT see it drop below 10.5 - 11.00
I’ve see old batteries that still start the engine drop as low as EIGHT VOLTS during cranking. When that happens all sorts of crazy electrical stuff happens and all sorts of weird DTCs show up after cranking.
BC
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Thread Starter
Pro
Joined: Feb 2005
Posts: 564
Likes: 1
From: Saint George Utah
If you turn the ignition switch on and the engine/alternator are not running wouldn't the voltage reading you'd get be essentially the battery voltage (less line losses for corrosion and such)?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
