P0318: Rough Road Sensor A Signal Circuit
What to do
The car will drive normally. If you have also seen misfire codes that appear only on rough surfaces, mention it — they are likely connected.
What this code means
A circuit fault in the primary rough road sensor. Without it the module cannot tell road-induced crankshaft variation from genuine misfire, so it either suspends misfire detection or risks false misfire codes on poor surfaces. Where a vehicle reports intermittent misfires only on bad roads, this is the code to look for first.
Likely causes
Start here
- Faulty rough road sensor · moderate
- Open circuit in sensor wiring · moderate
- Corroded or loose connector · easy
Less common
- Lost communication with ABS module · moderate
- Road damage to underfloor 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
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
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.
Sign in or create an account to add what you found about P0318.