Summit Benz

Finally got a scanner to check problem codes and check engine light. One problem that came up a lot on different areas of the car was "under voltage". I set the graph on my computer to view the live data while the car was at idle and the voltage was steady at 14.5v but then would drop to 0 then back to 14.5v. It kept this up the entire time idling.

So do I have a bad regulator? It does not sound like the alternator is bad or the battery but something is making the volt reading drop to 0. I am beginning my search at the battery checking connections.

N_Jay

First, check every connection between the battery, alternator and starter at both ends including grounds.

drgeeforce

What are the OBD Codes?

UtahJohn

going to 0 volts to me indicates a battery issue.

N_Jay

Why?

UtahJohn

it either means an external short or an internal short to ground. If the ground path of something was "open" then V would remain high. The only way to go to 0 on multiple items is if the battery was going to 0. Even if the alternator was not charging the system would remain near 12.8V battery voltage.

I suspect either a bad 12V cable from the battery, OR a battery plate is grounding internally (as they do when they get old).

YMMV

N_Jay

Pulling even a single leadacid cell to 0V would be a lot of current (and a lot of heat) going somewhere.


I would bet on an open not a short.


You could have an intermittent open in the battery but that would be very rare, and almost impossible assuming the battery still starts the car.


Look for an open, loose, or corroded connection.

Summit Benz

So I'm not too sure it is a battery or alternator issue. Today I kept the car off and watched the voltage and stayed between 11.8 to 12.5. Then started it and went to 14 and held. No drop offs ??? Thinking a ground somewhere. I tried to cut and paste all the DTC's that came up to show you. Sorry for it all but this is what I'm looking at fixing. Thanks j

Diagnostic Trouble Codes

Enhanced Powertrain
P2270:04 (2270) N14/3 (Glow Time Output Stage),

Tire Pressure Monitoring (TPMLS)
B1010 (9010) The Supply Voltage Of Component N88 (Tire Pressure Monitor Control Module) Is Too Low (Undervoltage)
Electronic Stability Program (ESP164)
C2001 (6001) The Supply Voltage Of The Control Unit Is Too Low (Undervoltage)


Air Conditioning (KLA164)
B100e (900E) Local Undervoltage At Circuit 30 (Voltage less than 9 V)
B1401 (9401) M16/28 (Left Blending Air Flap Positioning Motor): LIN Bus Communication Error
B1402 (9402) M16/29 (Right Blending Air Flap Positioning Motor): LIN Bus Communication Error
B1403 (9403) M2/12 (Rear Shutoff Flap Positioning Motor): LIN Bus Communication Error
B1404 (9404) M16/23 (Air Flap Actuator Motor, Left Center Vent):LIN Bus Communication Error
B1408 (9408) M16/13 (Left Defroster Nozzle Flap Actuator Motor):LIN Bus Communication Error
B1409 (9409) M16/14 (Right Defroster Nozzle Flap Actuator Motor):LIN Bus Communication Error
B1501 (9501) M2/5 (Fresh And Recirculated Air Flaps Actuator):LIN Bus Communication Error
B1806 (9806) Unknown Trouble Code Description. Please see your factory service guides for more any information.

Door Control Module - Rear End (HBF164)
B1010 (9010) Control Module N121/1 (Rear-End Door Closing Control Module) Has Detected Undervoltage
B1500 (9500) Component S62/26 (RWTS Button) 'Close Rear-End Door From Inside' Is Stuck In Switched Condition (Contact Is Stuck)
B1502 (9502) The Connection To Component B24/16 (Rear-End Door Opening Angle Recognition Sensor) Is Interrupted Or Has Short Circuit



Electric Seat Adjustment - FL (SSGF164)
B1060 (9060) No Normalizing Of Forward/Back Adjustment
B1202 (9202) Hall Sensor Of Component M27/2 (Left Rear Seat Height Adjustment Motor) Is Faulty
B1061 (9061) No Normalizing Of Front Height Adjustment
B1062 (9062) No Normalizing Of Rear Height Adjustment


Electric Seat Adjustment - Rear (SSGH164)
B1160 (9160) Switch S158/1 (Front Switch For Left Folding Backrest) Does Not Open
Instrument Cluster (KI164)
B112d (912D) The Preglow Lamp Is Faulty

Overhead Control Panel (OCP164)
B1010 (9010) The Voltage Was Less Than 9.0 V During 5 S
Upper Control Panel (UCP164)
B1036 (9036) Undervoltage Detection. Undervoltage Is Not Detected Until After 5 S And A Voltage Of less than 9.5 V
Parktronic (PTS164)
B1091 (9091) System 'Parktronic' has Detected Interference from the Vehicle's Surroundings
B1008 (9008) A42b3 (Left Inner Sensor, Front Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B100b (900B) A42b4 (Right Inner Sensor, Front Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B100e (900E) A42b5 (Right Center Sensor, Front Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B1014 (9014) A43b7 (Right Outer Sensor, Rear Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B1017 (9017) A43b8 (Right Inner Sensor, Rear Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B101a (901A) A43b9 (Left Inner Sensor, Rear Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B101d (901D) A43b10 (Left Outer Sensor, Rear Bumper): The Sensor Is Not Properly Fastened/Assembled Or There Is An Obstacle Near The Sensor
B1084 (9084) A44/3 (Rear PTS Warning Display): Cable Fault Or Communication Fault

Rear Control Panel (HBF164)
B1003 (9003) Switch N72/2s30 (Increase Blower Output Switch) Is Defective Or Has Been Operated For Longer Than 25 Seconds
B1005 (9005) Switch N72/2s35 (Head Area Air Distribution Switch) Is Defective Or Has Been Operated For Longer Than 25 Seconds
B1007 (9007) Switch N72/2s36 (Footwell Air Distribution Switch) Is Defective Or Has Been Operated For Longer Than 25 Seconds
B1010 (9010) Switch N72/2s32 (AAC [KLA] Temperature Control Switch) Is Defective Or Has Been Operated For Longer Than 25 Seconds. Right Direction Of Rotation
B1011 (9011) Switch N72/2s32 (AAC [KLA] Temperature Control Switch) Is Defective Or Has Been Operated For Longer Than 25 Seconds. Left Direction Of Rotation
B1030 (9030) Undervoltage Detection. Undervoltage Is Not Detected Until After 5 S And A Voltage Of less than 9.5 V

Signal Acquisition - Front (SAMV164)
B1010 (9010) The Component Or The Signal Line To The Component E2E6 (Right Side Marker Lamp) Has Open Circuit Or Short Circuit To Ground
B102a (902A) The Component Or The Signal Line To The Component F58kb (Wiper ON/OFF Relay) Has Short Circuit To Ground
B1043 (9043) Circuit 30 (1) Has An Undervoltage Of less than 7 V
B1045 (9045) Circuit 30 (2) Has An Undervoltage Of less than 7 V
B1064 (9064) Unknown Trouble Code Description. Please see your factory service guides for more any information.

Signal Acquisition - Rear (SAMH164)
B116e (916E) Right Trailer Taillamp Faulty(Short Circuit To Ground)
B1166 (9166) Left Trailer Taillamp (Short Circuit To Ground)
U0361 (C361) Event: Local Undervoltage At Circuit 30 (Voltage less than 9.5 V)
B1242 (9242) M21/9 (Right Vent Window Motor):Short Circuit To Ground Or Open Circuit
B116b (916B) Trailer Reversing Lamp Faulty(Open Circuit)

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N_Jay

I would ignore all the codes. They are just modules reacting to bad power.
Where did you put your meter then shows the zero voltage?

UtahJohn

disconnect the battery and monitor the battery voltage at the battery terminals. Anything below 12.4V is a bad battery. These symptoms are either a wiring issue (on the positive non-ground side) or an INTERNAL battery short.

Summit Benz

Soooo I just went out to clear my head and remembered something pretty relevant. This past winter we had a long cold spell and my car was completely dead. Had to put jumpers on twice. Thinking that I codeine was when the low voltage codes might have popped up.?

So now it is back to possibly a bad battery.

As far as the voltage reading. It is off the scan tool reading a live feed on the battery.

UtahJohn

Just pointing out that the scan tool reading of voltage is not necessarily battery voltage. That is the whole point, and possible symptom of your problem.

alx

Please replace your battery.

Summit Benz

I sure would like to take a easy battery swap instead of tackling those DTC codes. I had been eying a odyssey pc1350 per previous rec. still a good choice? So if you were me: install a new battery, then reset/clear all codes and see what codes reappear if any.?

Critter

If the battery has been dead twice now, change it out, with a new battery, clean the terminals as well as the battery cable ends.
A scan tool is not a reliable method for measuring bat voltage, spend a few bucks a buy a meter or hit Autozone or such place and get the bat tested. Dead battery does not make good reliable choices but will let you down as a daily driver.
Use a battery tender if the car sits for long periods.

N_Jay

Why not the ground side?

N_Jay

Again, why (Without testing it)?

N_Jay

Either have the battery tested, or put a charger on it overnight ten measure the voltage (with a meter) right after the charger comes off (Should be over 13.6), and a hour later. (Over 13.2 if disconnected, over 12.4 if connected to the car).

UtahJohn

If the problem was on the ground side it would not show a voltage of 0, like you state. It would effectively be an open circuit and the voltage would rail to 14.4V.

Critter

zero voltage is an issue with the measuring device, the car would be giving your much grief if it was in the 11V range but zero it would not be running.
car at rest 12.6-12.8V battery good
turn on lights, heater blower for 30 seconds then shut off , voltage should drop .1 or .2V max
Check for loose or corroded terminals,


car running 14.1 -14.2V idle, same when rpms are raised voltage regulator good as well as alternator

Summit Benz

So just to be clear can I leave the terminals attached to the battery and test with a volt meter at the terminals?

Critter

Yes attached is okay.
How old is the battery?

Summit Benz

It was replaced 10/12 by the stealership with oem mb battery about 30k miles ago.

Critter

Age is not the issue but having been dead does not help. If this was mine and the voltage checks seem okay then a load test is warranted

N_Jay

It would all depend on where the reference (ground) is picked up for the reading.