U0188 Low Generic / SAE

U0188: Lost Communication With Digital Disc Player/Changer Module B

Network and Communication Lost Communication

What to do

The car drives entirely normally. This is a second disc player — usually part of a rear-seat entertainment system, or an old-style multi-disc changer in the boot.

First, does your car actually have one? Rear entertainment was an expensive option that most cars were not built with, and if any of the entertainment equipment has been replaced with a second-hand unit from a better-equipped car, your car may now be looking for a module it never had. That is a coding correction, not a repair.

If the screens are in the roof or headrests, mention any work involving the headlining or the pillar trims — sunroof repairs, roof consoles, airbag work — and any sign of water getting in at the roof. That is where these live, and connectors get left unseated.

As at U0187, this is worth attending to even if nobody uses it. A failed module on the network can keep the car awake after it is locked and flatten the battery over a few days. If you would rather it was simply removed, that is reasonable — but it must be coded out properly, not just unplugged.

What this code means

A second disc player module has stopped being heard from. See U0187 for why a device nobody uses is still worth attending to, and U0489 for what a second player usually is.

A second player normally means a rear-seat entertainment system — a screen in a headrest or dropping from the roof, with its own mechanism — or, on an older luxury vehicle, a dash unit plus a boot-mounted multi-disc changer.

Which makes the configuration question the first one, exactly as at U0145. Rear entertainment was an expensive option fitted to a minority of vehicles on a shared loom, and infotainment components taken second-hand from a better-equipped vehicle bring its configuration with them. A module the vehicle never had, coded as present, reports lost communication permanently with nothing to find.

Where the equipment does exist and is roof-mounted, the causes are U0185's. A drop-down screen unit sits in the headlining, reached by the same work — sunroof repairs, curtain airbags, roof consoles — and fed by cables running through pillar trims that come off for other jobs. Water entering at the roof reaches it before it reaches anything else.

Otherwise everything at U0187 applies, including the network-awake argument and the option of decommissioning a redundant module properly.

Likely causes

Start here

Module not coded to the vehicle · specialist
Corroded or loose connector · easy
Water ingress into module · moderate

Less common

Symptoms

Components involved

Information, not instruction

CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.

Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

Community experience

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What makes one worth reading:

The car — make, model, year and engine. The same fault behaves differently on each.
What you measured, not only what you replaced.
What actually fixed it — or that nothing did, which is worth knowing too.