U0187 code meaning
Lost Communication With Digital Disc Player/Changer Module A
What U0187 means
U0187 opens the J2012 series for networked disc players and changers: module A is the main CD or DVD drive, while U0188 to U0190 cover B to D. In many older cars the changer sat apart from the head unit, in the glovebox, under a seat or in the trunk, and reported to it over a data line. U0187 has no public manufacturer documentation; GM lists no disc drives at all and the NHTSA bulletin index has no match. The radio records the code when the drive's periodic message stays away, following the logic GM gives for all loss-of-communication codes. Discs can then not be played or ejected, the rest of the sound system keeps working, and there is no MIL. A removed or never-fitted drive can also leave this entry behind.
U0187 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyEasy, DIY possible
- Typical labor0.3 to 2 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0187
- CD or DVD source missing or not selectable
- Disc cannot be loaded or ejected
- Other audio sources work normally
Common causes of U0187
- Most likelyDisc unit A without power or ground
- PossibleData line or connector to the changer (glovebox, seat, trunk) damaged
- PossibleDrive removed or head unit coded for a drive not fitted
- Less likelyDisc player/changer A faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Disc player moduleCAN bus wiring
What each part of U0187 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 87 | The exact fault in that area. |
What to do next
- Note U0187 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U0187
What does U0187 mean?
U0187 means "Lost Communication With Digital Disc Player/Changer Module A". U0187 opens the J2012 series for networked disc players and changers: module A is the main CD or DVD drive, while U0188 to U0190 cover B to D. It is a generic code, so it means the same on every make.
Is it safe to drive with U0187?
U0187 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will U0187 fail an emissions test?
U0187 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U0187 to fix?
Difficulty: easy. A typical repair takes 0.3 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will U0187 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.