U0187
Lost Communication With Digital Disc Player/Changer Module "A"
- Severity
- Low
- Driving
- No driving restriction
The control module has stopped receiving messages from digital disc player/changer module "A". The feature it provides is unavailable. Nothing about the way the car drives or stops is affected, and this can wait until it is convenient - though it is worth fixing rather than ignoring, because the underlying cause is often a power, earth or bus problem that will eventually affect something that does matter.
Possible causes
- CommonLow battery voltage or a discharged battery, dropping modules off the bus
- CommonBlown fuse or corroded earth on the supply to digital disc player/changer module "A"
- CommonConnector disturbed during stereo, dashboard or trim work
- CommonAftermarket head unit or amplifier fitted without the correct interface
- PossibleDamaged, chafed or corroded bus wiring
- PossibleFailed module
- PossibleModule not coded to the vehicle after replacement
What you might notice
- The feature is dead or unresponsive
- Display blank or frozen
- No sound, or sound from some speakers only
- System restarting repeatedly
- Occasionally a battery drain, if a module will not go to sleep
What to check, in order
- Check battery voltage and state of charge before anything else. A weak or failing battery drops modules off the bus and sets lost-communication codes with no wiring fault at all - this is the single most common false lead in this whole family.
- Ask whether an aftermarket stereo or amplifier has been fitted. Replacing a factory head unit that sits on the vehicle bus, without the proper interface, is one of the most common causes of these codes - and of a battery that goes flat when the car is parked.
- Check the fuses and earths for digital disc player/changer module "A".
- Check whether the connector was disturbed during recent trim, dashboard or stereo work.
- Note how many U-codes are stored. Several at once points at battery, earth or bus wiring rather than at several failed modules.
- If the car also has an unexplained battery drain, investigate this code rather than dismissing it. A module that cannot communicate may also fail to go to sleep.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
U00xxU01xxU02xxU03xxU04xxU05xxU06xxU07xxU08xxU09xxU0AxxU0BxxU0CxxU0DxxU0ExxU0FxxU10xxU11xxU12xxU13xxU14xxU15xxU16xxU17xxU18xxU19xxU1AxxU1BxxU1CxxU1DxxU1ExxU1FxxU20xxU21xxU22xxU23xxU24xxU25xxU26xxU27xxU28xxU29xxU2AxxU2BxxU2CxxU2DxxU2ExxU2FxxU30xxU31xxU32xxU33xxU34xxU35xxU36xxU37xxU38xxU39xxU3AxxU3BxxU3CxxU3DxxU3ExxU3Fxx
Network communication
U0100U0101U0102U0103U0104U0105U0106U0107U0108U0109U0110U0111U0112U0113U0114U0115U0116U0117U0118U0119U0120U0121U0122U0123U0124U0125U0126U0127U0128U0129U0130U0131U0132U0133U0134U0135U0136U0137U0138U0139U0140U0141U0142U0143U0144U0145U0146U0147U0148U0149U0150U0151U0152U0153U0154U0155U0156U0157U0158U0159U0160U0161U0162U0163U0164U0165U0166U0167U0168U0169U0170U0171U0172U0173U0174U0175U0176U0177U0178U0179U0180U0181U0182U0183U0184U0185U0186U0187U0188U0189U0190U0191U0192U0193U0194U0195U0196U0197U0198U0199