Intermittent Charging System Failure message with B1087 code

Yak · Post by **Yak** » 18 Oct 2019, 08:49

My wife's 2010 non-turbo has been intermittently showing warning lights and charging system failure messages. Yesterday it happened as I was returning home. I measured the voltage on the battery with the car running and the messages showing. Voltage was 13.8 . Every time this happens, I turn the car off and restart and it goes away. Battery shows 12.7 with car off. No issues starting, battery seems fine. It's also throwing a B1087 code, which is not well-defined.

Has anyone else seen this?

dasong · Post by **dasong** » 18 Oct 2019, 12:36

Same thing happening with my 2010 XC70 (Charging System Failure, not the B1087 code).
Going to replace the alternator next week.

Yak · Post by **Yak** » 18 Oct 2019, 12:50

Have you checked the voltage while the alert is active? I'm wondering why it's showing the alert yet the voltage seems to indicate that it is indeed charging.

dasong · Post by **dasong** » 18 Oct 2019, 12:53

I haven't. But next time the message comes up, I'll check it.
On other forums people seemed to think that the charging was fine, just that the communication between the ECM and the modulator on the alternator was getting messed up.

Yak · Post by **Yak** » 18 Oct 2019, 12:54

Keep me posted on how the alternator replacement goes. Thx!

Yak · Post by **Yak** » 17 Jul 2020, 15:00

Picking back up on a year old thread - I've since replaced the battery during the COVID shutdown, and today I plugged my OBDLink into it and took it for an oil change. On the way back I stopped at Autozone for an air filter. On the 3 mile drive home it lit up with Charging System Failure. The logs show the voltage at the PCM was running 13.6 - 13.8, voltage to the OBD plug was running 13.4 - 13.6. When I shut it off it dropped to 12.8 and 12.4 respectively. So it seems like it IS charging even when I get the failure message. Anyone have thoughts on what I might check next?

Post by **pgill** » 18 Jul 2020, 13:44

One possibility is the prem air sensor

For my S80 3.2 I would occasionally get B1087

I recently replaced the radiator (and prem air sensor)

This link has the service bulletin from Volvo

viewtopic.php?f=31&t=87687&start=50

Good luck

Paul

Post by **RickHaleParker** » 18 Jul 2020, 16:23

ECM-B108700 LIN Bus "A". General Failure Information. No sub type information

Condition
Engine control module (ECM) communicates continuously with Alternator control module (ACM) and radiator temperature sensor. Communication takes place via the LIN-net. The control module checks that its own signals go out on the LIN-net.

The diagnostic trouble code is stored if the control module detects: Communication is missing.

The control module's test for the diagnostic trouble code (DTC) starts in the event of: Ignition on.

Note! The control module can only detect the fault once the test has been started and the diagnostic trouble code (DTC) is stored when the conditions are met.

Substitute value
None.

Possible source

Contact resistance or oxidation on connections
LIN-cable short-circuited to voltage.
LIN-cable short-circuited to ground.
Open circuit on LIN-cable.
Internal fault in another unit in the same part of the LIN network.
Damaged engine control module (ECM).

Fault symptoms
Malfunction indicator light (MIL), on

Yak · Post by **Yak** » 22 Jul 2020, 17:36

Thanks for the replies. I had another user on a different forum suggest the radiator tamper sensor also. Since it's a cheap part, I'll replace that first and see what happens. I was told I might also need to have the software updated.

Post by **RickHaleParker** » 22 Jul 2020, 17:54

Yak wrote: ↑22 Jul 2020, 17:36 Thanks for the replies. I had another user on a different forum suggest the radiator tamper sensor also. Since it's a cheap part, I'll replace that first and see what happens. I was told I might also need to have the software updated.

Something on the LIN network. See above.

LIN = Local Interconnect Network.