The Lemon IndexThe engine takes too long to warm up.
Drive on, get it checked. You can usually keep driving. Have the code read at your next service or within a few weeks.
Thermostat stuck open. Then: faulty coolant temp sensor.
Owners named P0126 in 7 complaints to the U.S. government, most often on the Mazda CX-5.
Cars owners report it on
Complaints that name P0126, by model. Raw counts, not a failure rate: popular models get more complaints.
Years owners report it on most: 2019 Mazda CX-5
The details
What P0126 means
The engine takes too long to warm up.
Can I drive with P0126?
Drive on, get it checked. You can usually keep driving. Have the code read at your next service or within a few weeks.
29% of the owner complaints that name P0126 also say the car overheats. A complaint can describe more than one problem, so this doesn't prove the code caused it.
Common causes of P0126
- Thermostat stuck open
- Faulty coolant temp sensor
A shop should confirm the cause with a scan and tests before replacing parts.
What owners describe
- Overheats: 29% of complaints
Share of complaints naming the code whose text also mentions each problem.
Model years that report P0126 most
2019 Mazda CX-5 (2).
Related codes
P0128 P0123 P0122 P0121 P0120 P0131 P0133 P0117
Quick answers
What does P0126 mean?
Insufficient Coolant Temperature for Stable Operation. The engine takes too long to warm up.
Can I drive with P0126?
Drive on, get it checked. You can usually keep driving. Have the code read at your next service or within a few weeks.
What causes P0126?
Thermostat stuck open; Faulty coolant temp sensor.
Counts: NHTSA owner complaints whose text names P0126. A complaint is an owner's report, not a diagnosis. Meanings: the standard SAE J2012 definitions in our own words; manufacturer codes only where verified for that make. General information, not repair advice for your car.