B1325 – Control Module Power Circuit Low/High Voltage (Chevrolet)
| Code | Fault Location | Probable Cause |
|---|---|---|
| B1325 | Control Module Power Circuit Low/High Voltage (Buy Part On Amazon) |
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Table of Contents
- What Does Code B1325 Mean?
- Where is the B1325 sensor located?
- What are the common causes of code B1325?
- What are the symptoms of code B1325?
- Get Help with B1325
What Does Code B1325 Mean?
SPECIAL NOTES: As with many other trouble codes, Chevrolet-specific trouble code B1325 is listed with different definitions by different resources. In this case, some unofficial sources list code B1325 with the definition “Control Module Power Circuit Low/High Voltage”, while official GM and Chevrolet sources list code B1325 with the definition “Device power #1 (low current #1) circuit malfunction”.
At first reading, the two definitions might appear to be different, if not incompatible, but the differences merely involve differences in terminology used in different automotive markets. We need not delve into the specifics of these differences here, beyond saying that in the context of this particular trouble code, the terms “Control Module” and” Device Power” both refer to an abnormal power supply to a particular control module other than the PCM (Powertrain Control Module).
Therefore, to avoid confusion, this article will use the definition “Device power #1 (low current #1) circuit malfunction” since this definition indicates the nature of the problem, i.e., a low input current. Note, also, that most recent official GM sources list this code with one of two possible suffixes, these suffixes being-
- DTC B1325 (03) – Device Power #1 – “Circuit Voltage Below Threshold”
- DTC B1325 (07) – Device Power #1 – “Circuit Voltage Above Threshold”
Therefore, for the sake of clarity, the most accurate rendition of this particular GM/Chevrolet-specific trouble code would be DTC B1325 (03) – Device Power #1 – “Circuit Voltage below Threshold”. END OF SPECIAL NOTES.
Based on the above explanation and depending on the source consulted, OBD II fault code B1325 is a Chevrolet-specific trouble code that typically sets when one of four possible control modules detect an abnormally low battery voltage for a predefined period. Note that since the affected modules draw their power feeds directly from the battery, the battery voltage at any given time is critical for their operation.
In terms of specifics, the following control modules monitor the battery voltage directly and continuously through the B+ (positive battery) terminal, but note that a technical description of the operational relationships between them falls outside the scope of this article-
- The body control module (BCM)
- The instrument panel cluster (IPC)
- The radio/infotainment system
- Sensing and diagnostic module (SDM)
As a practical matter, one, or all of the control modules listed above will set trouble code B1325 when one or all of them detects a battery voltage that falls below 9 volts for longer than 5 consecutive seconds.
When this occurs, the control module that first detects the fault condition will prevent the setting of any other trouble codes and disable all its outputs, except for-
- transmissions on the GMLAN serial communications network
- the Run/Crank relay, which is only disabled after a delay of 3 minutes
In practice though, the action of one control module disabling all its outputs sometimes also disables some or all of the outputs of related control modules. For instance, if say, the BCM (Body Control Module) disables all its outputs, everything that depends on that control module to work will stop working, but in addition, some outputs of the radio/infotainment system, the IPC (Instrument Cluster), and/or the SDM (Sensing and Diagnostic) module will or might also be disabled. See the section on “Symptoms” for more details.
Where is the B1325 sensor located?
This image shows an alternator taken from a Chevrolet Aveo application that consistently undercharged the battery, which is the root cause of code B1325 on GM/Chevrolet applications, more often than not.
Therefore, all diagnostic procedures related to codeB1325 must always start with a) an inspection of the charging system, and b) verifying that all components in the charging system work as designed and intended.
What are the common causes of code B1325?
Common causes of code B1325 could include one or more of the following-
- Defects in the charging system that prevent the battery from achieving and/or maintaining a full charge
- Defective battery, or battery terminals that are loose, corroded, or otherwise damaged
- Failed, or failing alternator components such as the bridge rectifier and/or voltage regulator if the alternator has a built-in regulator
- Damaged, burnt, shorted, disconnected, and/or corroded wiring and/or electrical connectors in the charging system
- Poor engine and/or chassis ground connections, or the intermittent loss of ground connectivity
- Poor, sloppy, or incorrect fitment/installation of aftermarket electrical accessories such as unauthorized audio equipment and auxiliary driving lights
- Previous, but poorly executed electrical repairs and/or modifications
- Disconnecting the battery for any reason
- Failed control module(s), but since this is an exceedingly rare event, the fault must be sought elsewhere before any control module is condemned out of hand
What are the symptoms of code B1325?
The symptoms of code B1325 on GM/Chevrolet applications largely depend on which of the implicated control modules detected and stored the code. Nonetheless, the possible symptoms span a bewildering variety that could include some of the following, but note that the list below is neither complete nor exhaustive-
- Stored trouble code(s), but note that warning lights may or may not be present
- The failure of all body control functions
- All instruments in the instrument cluster may be disabled
- It may be impossible to extract any fault codes other than B1325
- A no crank/no start condition will be present 3 minutes after the code was set and stored; this is an important point because the principal diagnostic test for this code involves measuring and verifying the charging voltage with the engine running
- On automatic models, it may be impossible to move the gear selector out of, or into any position
NOTE: AS a general rule, code B1325 and all symptoms will usually resolve when the root cause of the problem is found and corrected. However, from the above, it should be clear that diagnosing and resolving this code on GM/Chevrolet applications can sometimes be extremely challenging, even for professional mechanics. Therefore, we do not recommend that non-professional mechanics attempt any diagnostic and/or repair procedures when code B1325 is present on any Chevrolet application.
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I have a no start issue. I just bought the car the guy said it will start and run until it gets up to running temp then the car will die. Well that happened after i bought it now i can get it to start at all. It acts like a dead battery and just clicks and sometimes it will crank but real slow. I have replaced the battery and it will also do that even when on a battery charger and hooked up to jumper cables. One of the codes says low voltage to module #1
So check engine light just came on today so I scanned it and I’m getting codes on BCM:
B1325-03
B3949-05
B3950-05
U2100-00
I also did a battery and alternator test and it said that my battery was bad even tho I just replaced it a couple of weeks ago
Hello Levi. I believe you may have a bad or loose ground at G105. It is kind of right split between the engine and transmission. See if you can communicate with the TCM and bcm. Repair the ground and see if the codes come back. Good luck.
My vehicle has been marking oil change needed soon but I had the oil change not long ago and it hasn’t reach the date nor mileage to take it back for it. My car stopped in the middle of the road and shut off all functions. Called one of my friends to check it out and found multi-purpose fuse was cracked and had it replaced but didn’t fix anything. Later had my friend check again and when I tried powering on my car, the check engine light was on and the dashboard screen said low battery voltage and we proceeded on buying a new battery but it didn’t change a thing. We checked the voltage of the old battery and it was still functional. We ran a code and it marked B1325 so if nothing we did was a bit of solution to the problem, is it better to have it sent to a mechanic at the dealer or is there something we have not tried?
Hi all I just got a 2008 saturn outlook xr. Only thing I was told about was the battery light on. So me being old school thought no problem. Just replace the alternator or fuse. Well 3 alternators 2 batterys and a fuse. And still don’t charge. It says lamp wire fault. But the light works and I can’t find a broken wire. So I’m lost. And It rained here and I went out to work on it and it was soaked on the floor. I’m guessing leaking windshield or hose for sun roof. But there is modules and all that every where on this. I’m wondering if that’s why my charging problem can’t be traced. Maybe bcm, ecm or something?
Hi Drew. With all of the research I did and a few experiences with Saturns, the sunroof seems to have problems leaking onto the floor of your vehicle. The affected area affects your charging output. So, that being said first is the usual culprit. The Sensing Diagnostic module. This will normally cure your problem. The alternator is charging, but not keeping up with your battery. Next, replace the connector as well to the SDM module. One last thing people have done to help the issue is replace your passenger presence system. I hope this helps, and you will be on your way to a good charging system. 😁.
Hey I have the infamous 06 hhr that, after less than 2 months of ownership, has gone haywire. I get code 1325 only sometimes and only if I start it, go a little ways and then shut it off. Repeat that 2-3 times and then it won’t start. Have to jump the battery and it goes away. The reason I’m starting it and shutting it back off in a short period of time Is because if I sit in traffic, or a drive through line and idle for a minute or more, my traction control light comes on, making my transmission shift really hard and I get codes 0172, 0300 and 0561. After replacing spark plugs and fuel injectors is when this all started.
Paige. There is a secondary diagnostic link connector usually in these hhrs. It’s called an assembly line diagnostic link. It is there for tracking, monitoring, and maintenance scheduling. Especially if it was a fleet vehicle before. Check to see if there is a device plugged into it. This is something you can unplug yourself. It has been linked to these shifting, drivability issues, and these trouble codes you’ve mentioned. Corporate bulletin number 13-08-116-001A.
Wow, Nathaniel, thank you so much! First useful information I’ve received so far. Do you have any idea where this secondary link connector would be located? Keep in mind that I’m a newbie DIY’er, so take it easy on me…;)
I know where the main OBDII port is, by the way…
You are welcome. Glad if I can be of help. If it is for car insurance monitoring, it will be plugged in to your obd2 connector and say State Farm, or whoever the company is. A secondary obd connector can also be right next to your obd2 connector and say diagnosis on the cap.
If it is a fleet tracking device interface, then it will be a red connector right above your parking brake pedal. They will be insulated red and blue wires going to the device. Hope with this info you will be able to find it ok. :-).
Below is a link that has pictures for locations as well.
https://static.nhtsa.gov/odi/tsbs/2013/MC-10134671-9999.pdf
Here’s my next dilemma–pretty sure it’s not connected to my main obd because I plugged my scanner into that to read the codes to begin with, so I’ll be looking for an alternate location. An interesting tidbit: the last owner was a retired State Farm agent…I think he’s a bit of a slickster. The car has definitely been wrecked ( many subtle yet different colors of paint, a wrinkled metal piece hidden conveniently under the hood, drivers side front fender doesn’t quite meet up right with the bumper, hood rubs the drivers door) but it doesn’t show anything on carfax. It had really low miles so my dad bought it without investigating like he usually would have. And here’s a question: the ecu ground right in front on the frame–instead of being attached directly to the frame, it looks like someone tried to weld over a hole in the frame and then attached the ground bolt THROUGH the welded spot. Could that be causing a short to the ECU?
Hello. That is interesting that he is a State Farm agent retired. I bet this car got tampered with and had a monitoring device. Almost certain. Oh. That is interesting. The welded spot is some tampering. Is the ground wire in good shape? If the ecu ground strap can reach the engine block, I would just ground it there to be safe and replace it if you question it at all. But yes, it can cause a short in the ecu to answer your question.
My Chevy Malibu Lt 3.6 has a air bag light and a cheak engine light on it says control module power circuit low voltage I replaced the 02 sensor and air mogler air flow now light is still on cheak engine light now my ex change my spark plugs now there was oil in the spark plugs holes …now with airbag light on to service it could it be a low battery let me no or bad turmoil…there old on battery ok I’m kathy
Hello Kathy. So, for one of the issues, the code b1325, it sounds like the battery is too discharged to power all the modules at the same time. For this issue, I would suggest replacing your battery then seeing what lights come back on. That will tell you which areas of the car are still having problems. The airbag light may stay off if it was just a battery issue. Oil in the spark plug holes means the tube seals are leaking and the valve cover gasket will need replaced. If the airbag light comes back on, then re post with the new code that comes up.
U0001 B1325
In IPM
U2100:00
U2100:72
U2105:00
U2108:00
In SIR
B0081:71
This car has an intermittent no start but what irks me most is that it has a no shutoff issue when running
Alt works however some days it charges at 15 v and sometimes 13.2-13.4 v
Also David, do re-check the alternator’s output after the battery. 13.2 volts is not enough charge.
Thanks guys new battery from autozone p 101. All specs are as they should be
Battery voltage 14.3
Still have an airbag light
Car will not shut off by key
Must pull the ipc or ecm fuse
Hello David. It sounds like the alternator is trying to keep up with charging a discharged battery. These failed communication codes will usually be set when there is low power to the affected modules. Try replacing your battery. The codes should stay away after this.