What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer wording
Source wording can vary by vehicle and suffix. It is shown as written, not as a universal diagnosis.
P0137CIRCUIT LOW INPUTP0137HO2S CIRCUIT LOW INPUTManufacturer communications
3Original wording in English
MAZDA
Reported code forms P0137
SOME CUSTOMERS MAY COMPLAIN ABOUT A CHECK ENGINE LIGHT ON WITH DTC P0137 (HO2S CIRCUIT LOW INPUT) STORED IN PCM MEMORY. THIS MAY BE CAUSED BY REAR HARNESS DAMAGE FROM AN AFTERMARKET ALARM SYSTEM INSTALLATION.
MAZDA
Reported code forms P0137
IF YOU ENCOUNTER A VEHICLE WITH DTC P0137 (CIRCUIT LOW INPUT), CHECK THE REAR HARNESS AT THE RED CIRCLED AREA IN THE FOLLOWING DIAGRAM. IF AN AFTERMARKET ALARM SYSTEM IS INSTALLED, THE REAR HARNESS MIGHT HAVE RECEIVED…
MAZDA
Reported code forms P0137
IF YOU ENCOUNTER A VEHICLE WITH DTC P0137 (CIRCUIT LOW INPUT), CHECK THE REAR HARNESS AT THE RED CIRCLED AREA IN THE FOLLOWING DIAGRAM. IF AN AFTERMARKET ALARM SYSTEM IS INSTALLED, THE REAR HARNESS MIGHT HAVE RECEIVED…
Check vehicle applicability
3A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.