Alternator Inconsistent Charging

Post by **hummer3t** » Sun Feb 19, 2023 3:15 pm

Have a 2013 Infiniti. Vehicle needed a jump recently and while driving back home I noticed the dashboard battery charging indicator was fluctuating between charging and then dropping to the mid-point. I ran a multimeter test from the battery while the vehicle was running, and the indicator went from 12 to 14+ randomly. I decided to change the alternator (vehicle has 151000 miles) and afterward the indicator on the dash was showing charging, but after driving for a few miles the dash indicator started fluctuating again between charging and back to the mid-pint. I again ran a multimeter test from the battery and got the damn same results 12 to 14+ randomly. What am I missing?

Post by **VStar650CL** » Sun Feb 19, 2023 3:34 pm

Chances are the "smart" charging system on your QX is getting stupid because of a bad battery current sensor or a bad battery ground cable. It's a common issue on all 2nd generation Armadas and QX56/80's. Voltage-drop your ground cable, clean or replace it if it's bad. If it checks okay, either replace the current sensor (expensive) or disable the smart charging system (cheap). Your setup will be identical to the one in this thread:
qx80-battery-t631452.html

Post by **hummer3t** » Tue Feb 21, 2023 3:07 pm

Forgot to mention that when the dash charging indicator is at the mid-point both the battery indicator and brake both illuminate and then go out. Vehicle shows charging intermittently. I will check the ground cable, and if that doesnt work consider the "cheap" alternative. Thanks.

Post by **VStar650CL** » Tue Feb 21, 2023 3:43 pm

If you're getting a light, that's different. The smart charge will never cause a generator light. Chances are the regulator in your alternator is headed south.

Post by **hummer3t** » Tue Feb 21, 2023 4:01 pm

Ground cable okay. I unpinned the red wire shown in the thread and plugged the connector back in and the dash eliminates but the vehicle doesn't crank over at all.

Post by **hummer3t** » Tue Feb 21, 2023 4:03 pm

I brought the original alternator to the shop to be tested and it passed the test. I just installed the replacement and it's giving me the exact same issues as the original alternator.

Post by **hummer3t** » Tue Feb 21, 2023 4:10 pm

I found the current sensor on the Infiniti site, before I purchase is there any way to test the original sensor?

Post by **hummer3t** » Tue Feb 21, 2023 5:02 pm

I reconnected the red wire and the vehicle started without issue. I checked the sensor connection and drove the vehicle and it was charging almost to the 3/4 mark and eventually dropped to just before the 1/2 mark. Unfortunately, when I pulled into the driveway and put the vehicle into park it dropped to 1/2 and the battery & brake light illuminated briefly and then the arrow moved slightly, indicating charging. Should I replace the sensor?

Post by **VStar650CL** » Tue Feb 21, 2023 5:12 pm

hummer3t wrote: ↑
Tue Feb 21, 2023 4:10 pm
I found the current sensor on the Infiniti site, before I purchase is there any way to test the original sensor?

Not with diagnostics. Unfortunately, part of the problem with the smart charge is that even Nissan's Consult3+ diagnostics for the sensor range from absent to abysmal. The best way to confirm is to disconnect the sensor and see if the bad behavior stops. That will cause codes in the BCM but no warning lights. There's no way disconnecting the smart charge wire can cause a no-start, so something's wrong there. There's a Red and a Red/White wire on that connector, the Red/White is for the Starter Control Relay and will cause a no-start.

Post by **hummer3t** » Tue Feb 21, 2023 6:05 pm

I may have disconnected the incorrect red wire. I disconnect the heavy gauge red wire that is in the cluster with the heavy gauge blue wire also. That may explain why I got the no-start. Hard to tell from the photograph which cluster the red wire was associated with. I'll check it all out tomorrow.

Post by **VStar650CL** » Tue Feb 21, 2023 9:31 pm

The smart charge wire is light gauge, probably 24~26 AWG (all are light gauge on the correct connector). If you look down at the IPDM in place, there are two small connectors toward the front of the vehicle, one black and one white. The white one is E13.

Post by **hummer3t** » Wed Feb 22, 2023 2:46 pm

Attached are pictures of the electrical box. The location of the plug with the red wire differs from your picture.

Post by **VStar650CL** » Wed Feb 22, 2023 3:05 pm

: IPDM.jpg (43.54 KiB) Viewed 3230 times

Post by **hummer3t** » Wed Feb 22, 2023 3:40 pm

That's what I assumed, and wish I could say that was successful, but after cutting the red wire you indicate, the vehicle would not start, and the windshield wiper ran. The dash lit up and the "key" indicator illuminated on the dashboard.

Post by **hummer3t** » Wed Feb 22, 2023 3:47 pm

I have reconnected the red wire and the vehicle started without issue and the windshield wiper did not turn on by itself. The only issue that remained is the "key" indicator is still illuminated on the dashboard, not sure what that's all about? I'm going to disconnect the sensor as you previously suggested and see what result I get.

Post by **hummer3t** » Wed Feb 22, 2023 5:32 pm

Disconnected the sensor and drove the vehicle for 15 minutes, charging indicator was just below 3/4-mark entire drive. Connected the multi-meter and received a favorable "consistent" reading. Based on this test I believe the sensor is the culprit and will replace. Cannot purchase locally and will order on-line. In the interim is it safe to drive the vehicle without the sensor connected or can the battery be overcharged, or any other component of the vehicle be damaged?

Post by **VStar650CL** » Wed Feb 22, 2023 6:14 pm

hummer3t wrote: ↑
Wed Feb 22, 2023 3:40 pm
That's what I assumed, and wish I could say that was successful, but after cutting the red wire you indicate, the vehicle would not start, and the windshield wiper ran. The dash lit up and the "key" indicator illuminated on the dashboard.

That's bizarre, I've literally done that on scores of Armadas and tens of QX56/80's without the slightest misbehavior. The wiring diagrams and IPDM interfaces are identical on all of them. Color me puzzled. Maybe your IPDM has an issue in the driver circuit.

Post by **hummer3t** » Sun Mar 19, 2023 10:53 am

Well, here's the latest. After driving since the 22nd of February without the sensor connected, I've received a consistent charging indication as I noted above when I first disconnected the sensor. I went ahead and purchased an OEM sensor and installed it today and initially the charging indication was consistent, reading just above the mid-point, but after 5 minutes of driving it began to fluctuate and drop to the mid-point and the battery light came on, and then it would rise above the mid-point indicating charging. So, it's not the sensor but whatever the sensor is connected to? The IPDM as referenced above?

Post by **VStar650CL** » Sun Mar 19, 2023 12:02 pm

The gen1 Armada/QX are a little different from other N/I models, the Current Sensor feeds direct to the ECM and not the BCM like most others.

Post by **hummer3t** » Thu Mar 23, 2023 5:07 pm

Okay, if that's the case, is the ECM at fault?

Post by **VStar650CL** » Thu Mar 23, 2023 6:02 pm

If it's a known-good sensor and the ECM is charging incorrectly when it's connected, that certainly suggests something is wrong in the A/D circuit the ECM uses to read the sensor. I don't think there's any good way to check it. The only thing you get from the diagnostic PID is sensor voltage, but the FSM doesn't really specify what a healthy reading is or how the ECM/BCM acts on it. That's why the stupid things drive us crazy.

Post by **hummer3t** » Sat Sep 16, 2023 9:49 am

Been driving the vehicle without the battery current sensor connected and to-date haven't had any issues, and no codes appearing until today; code P1557 Battery Temperature Sensor. Is this because the battery is receiving a constant charge?

Post by **hummer3t** » Sat Sep 16, 2023 9:55 am

or because the battery sensor is disconnected?

Post by **VStar650CL** » Sun Sep 17, 2023 7:59 am

The temp sensor and current sensor are integrated on the Y62 Armada/Qx80's. Breaking the one connector disconnects both.

Post by **hummer3t** » Thu Sep 21, 2023 7:05 pm

Thank you for the response, so I shouldn't be concerned about the code?

Post by **VStar650CL** » Fri Sep 22, 2023 6:01 am

No, if it isn't lighting the MIL or the generator lamp, I'd say forget about it and happy motoring.

Alternator Inconsistent Charging

Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Re: Alternator Inconsistent Charging

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums