U0113: Lost Communication With Emissions Critical Control Information
What to do
The car will drive normally, which is the difficulty with this one.
What has been lost is the vehicle's ability to demonstrate that its emissions equipment is working. Two things follow. It will not pass an emissions test — not because it is polluting, but because its self-checks cannot complete, which is a different thing and a confusing one to be told. And on a diesel with an inducement system, the vehicle may begin a countdown that ends in a restricted speed and eventually a refusal to restart. That countdown runs while the car drives perfectly, so there is nothing to prompt you.
Get it read properly. Whatever other communication codes are stored alongside this one identify the module that actually stopped talking — this code on its own says only that something in the emissions chain is missing, so it is the accompanying codes that matter.
What this code means
Information the vehicle needs in order to run and verify its emissions systems has stopped arriving.
This code is unusual in the family because it names a class of information rather than a box, and that is deliberate. Emissions compliance on a modern vehicle is distributed: the reductant dosing module, the particulate filter's own controller, the exhaust temperature and NOx sensor modules and the engine module all hold pieces of it, and the standard needed a way to say that the set has become incomplete without naming which member is missing.
The consequence is legal rather than mechanical, and it follows the pattern the corpus has recorded since P2047. The vehicle can no longer demonstrate that its emissions systems are working, so it does what it does when it cannot: readiness monitors will not complete, and on a vehicle with inducement the countdown to a speed restriction and then a refusal to restart begins. None of that produces a symptom while it is happening. The car drives normally and the deadline runs anyway.
So the practical reading is: nothing feels wrong, nothing is being damaged, and there is a clock running. Which is precisely the situation people leave alone.
Diagnostically, this code is a pointer rather than an answer. Whatever other communication codes are stored alongside it name the module that actually went quiet, and that is where the work is.
Likely causes
Start here
- Another module holding the bus down · specialist
- Damaged data bus wiring · moderate
- Corroded or loose connector · easy
- Failed power or earth supply to the module · moderate
Less common
- Software calibration out of date · specialist
Symptoms
Components involved
Information, not instruction
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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.
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