VOLVO
IGM-U1A4B82 - Control Module Processor B. Bus Signal / Message Failures. Alive / sequence counter incorrect / not updated
System
Unknown System / Manufacturer Specific
Volvo models this fault code applies to
Applies to the following models:
1 modelV60 (2011–)
Show models by year and engine (2)
What does this fault code mean?
Although the code is named sequence counter, it applies to an internal fault in the microprocessor of the high voltage generator control module (IGM). The fault is only checked once the combustion engine is running, and the code is stored when the conditions are met.
Possible causes
- Software fault in the IGM
- Internal fault inside the ISC voltage converter
What you can do
- 1Read out and note the code, clear it and start the car to see whether it returns
- 2Have a workshop check that the IGM has current software and install new software if needed
- 3If the fault remains, have a workshop look at the ISC voltage converter
- 4The high voltage system may only be handled by a workshop; do not work on it yourself
Symptoms you may notice5
- Warning symbol and text message in the display
- Warning about power supply problems from the alternator and charge regulator
- Charging of the high voltage battery while driving is absent, reduced or not working correctly
- High voltage battery is discharged or charges poorly
- HYBRID drive mode: the combustion engine is active all the time or too often
What the fault can affect1
- The high voltage battery cannot be charged by the combustion engine
General guidance for car owners. Diagnosis on the car can point to a different cause.