VOLVO
IEM-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?
The electric rear axle drive module (IEM) monitors its internal components and the communication with the clutch control for the electric rear axle (DCC). The code is stored when the microprocessor has an internal fault, or when the DCC is not communicating properly. The fault is only checked once the test has started at ignition on.
Possible causes
- Software error in the electric rear axle drive module (IEM)
- Internal fault inside the ISC voltage converter
What you can do
- 1Read out, clear the code, start the car and see whether it returns
- 2Have a workshop check that the connectors between the IEM and the clutch control are fully engaged and free from corrosion
- 3Have a workshop with diagnostic equipment check the communication with the clutch control and update the software if needed
- 4If the fault remains, have a workshop check the clutch in ERAD
- 5Do not work on the electric rear axle or its high voltage system yourself; have a workshop carry out those checks
Symptoms you may notice4
- Warning symbol and text message in the display
- PURE drive mode disengages by itself or is not available
- AWD drive mode disengages by itself or is not available
- HYBRID drive mode runs with the combustion engine active all the time or too often
What the fault can affect3
- Electric propulsion is not possible
- The clutch in ERAD may be mechanically damaged
- Brake energy regeneration from the electric rear axle ERAD is not possible
General guidance for car owners. Diagnosis on the car can point to a different cause.