U0149: Lost Communication With Serial Data Gateway Module D
What to do
Expect features on the converted or specialist part of the vehicle to have stopped, rather than anything to do with driving.
Four of these translator modules effectively means a converted or commercial vehicle. Go back to whoever built or converted it before a general workshop — that wiring is their work, and the fault is nearly always where their harness meets the vehicle's.
One thing worth watching for and reporting, because it is the fastest clue there is. Does the fault appear after a long drive and clear again by the next morning? These modules work continuously and get hot, and a connection that fails warm and recovers cold is a loose or corroded terminal rather than a failed module. Nobody will find that on a cold vehicle in a workshop unless you tell them.
On an ordinary car this most likely means the car has been told it has a module it does not have, which happens after a second-hand part is fitted. That is a coding correction and there is nothing to repair.
The vehicle is normally safe to drive. Do not use any affected body equipment, trailer or lifting gear until it has been checked.
What this code means
A fourth gateway module has stopped being heard from. See U0146 for what a silent gateway does to everything behind it, and U0148 for why a vehicle carrying this many is almost certainly a converted or commercial one.
One numbering note that will otherwise look like a mistake. The Invalid Data Received family's gateway D sits in the letter-suffixed part of the U044x range rather than at a decimal number, so this code has no counterpart there — the sequence in that family runs A, B, C and then E at U0451. This one does have a decimal number, and the pair of ranges simply do not run parallel.
Beyond that, everything at U0148 applies unchanged: establish whether the module is fitted, and if it is, look at the join between the converter's wiring and the vehicle manufacturer's before anything else.
One addition worth making at this point in the family, because it applies to all of them and is easiest to state here. Gateways fail in a specific way that a meter finds quickly: they are the most heavily loaded modules on the vehicle and among the hottest. A gateway passing traffic between four or five networks is working continuously whenever the vehicle is awake, so its supply, its earth and its own connector see more thermal cycling than almost anything else on the network. A fault that appears after a long run and clears overnight is that, and it is a connection rather than a module.
Likely causes
Start here
- Corroded or loose connector · easy
- Poor wiring splice in an aftermarket installation · moderate
- Module not coded to the vehicle · specialist
- Heat damage to sensor or wiring · moderate
Less common
- Intermittent wiring fault · 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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- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
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