U0197: Lost Communication With Telephone Control Module
What to do
Do not pick the phone up. That is the whole of the safety advice here, and it needs saying because this fault creates exactly that temptation.
The hands-free system is what makes taking a call in the car lawful in most places. When it stops working, the pressure is to hold the phone instead — dangerous, and expensive if you are caught. Let calls go to voicemail, and if one genuinely has to be answered, stop properly first.
One check tells you whether the usual free fix is worth trying. Go into the car's settings menu and see whether the phone system is still listed there at all.
If it is listed but will not pair, delete the pairing on both the car and the phone and start again from scratch. That fixes a surprising number and costs nothing.
If it is not listed at all, the car cannot see its own phone module, and no amount of re-pairing will help. That needs a garage.
Two more things worth checking, because on most modern cars the phone system is not a separate box. Does the radio still work? Do the connected services and the phone app still work? If either has gone too, that is where the fault is, and saying so stops the wrong thing being repaired.
The car is otherwise entirely fine to drive.
What this code means
The telephone control module has stopped being heard from. The general reasoning is at U0100, and U0498 makes the argument that gives this page its severity — hands-free operation is what makes using a telephone in a moving vehicle lawful in most jurisdictions, so a driver whose hands-free has stopped is a driver under pressure to pick the phone up.
That instruction comes first and does not change: let calls go to voicemail, and stop the vehicle if one must be answered.
Silence changes which of U0498's remedies is worth trying, and it is worth being honest about that rather than repeating the list.
U0498's free fix — deleting the pairing on both sides and starting again — is much less likely to help here. A module that is not communicating with the vehicle will not appear in the vehicle's own menus to be paired at all. So the test that separates the two situations is simple: can the vehicle still see its own telephone module in its settings?
- Visible but not pairing — the pairing is stale, and re-pairing is worth a try.
- Not visible at all — the module is not there as far as the vehicle is concerned, and pairing cannot help.
On most modern vehicles the telephone function is not a separate box. It lives inside the head unit or the telematics module, so if the radio has gone too, U0184 is the better page; if connected services have gone too, U0198 is. Establishing which saves the wrong repair.
Where it is genuinely its own module, the aerial matters — the phone connection uses the roof antenna at U0185 — and so does a non-original head unit, which frequently replaces the hands-free function with something the vehicle does not recognise.
Likely causes
Start here
- Blown fuse or failed supply · easy
- Module not coded to the vehicle · specialist
- Aftermarket head unit fitted in place of the original · moderate
- Corroded or loose connector · easy
Less common
- GPS antenna disconnected or damaged · moderate
- Damaged data bus wiring · moderate
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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