P111A On Mazda, the engine coolant temperature has gone above its limit

Mazda engine coolant temperature high

P111A in short

On Mazda, P111A means the engine coolant temperature is high. Mazda bulletins tie it to the wrong production coolant concentration on 2014-2015 Mazda3 and to fan control software on 2019-2020 CX-5. Owners report limp mode and a cracked head, so stop driving if it overheats.

P111A is a Mazda-specific code. Mazda describes it as engine coolant temperature high, and the NHTSA complaints we read give the same meaning from a technician scan.

On the 2014-2015 Mazda3, Mazda says the high temperature light can come on in extreme cold, with poor heater output, because the coolant concentration may not have been set correctly at the factory. On the 2019-2020 CX-5, the cause may be software that runs the cooling fan wrongly.

Real overheating is also reported: a 2019 CX-9 went into limp mode at 251.6 F, and a 2018 CX-9 had a coolant leak and a cracked cylinder head. We have not sourced meanings for other makes.

Pick your make

P111A is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

Most likely causes

  1. Incorrect coolant concentration from production (2014-2015 Mazda3)

    Supported by vehicle data
    Why it ranks here
    Mazda bulletin 01-022-15-3083 says the production coolant concentration may not have been set correctly, causing freezing in extreme cold and the high temperature light with P111A.
    What would change this
    Rises if it happens in extreme cold with poor heat on a listed Mazda3. Falls if the coolant tests at the correct concentration.

  2. Cooling fan control software (2019-2020 CX-5)

    Supported by vehicle data
    Why it ranks here
    Mazda bulletin 01-007-20-3691 says improper control module software may make the fan run improperly and set P111A with overheating and weak A/C; it does not apply if the concern happened at high speed.
    What would change this
    Rises if overheating happens at idle or low speed on a listed CX-5. Falls if it happened at high speed or the fan runs correctly.
    How to test the engine control module (ecm / pcm)

  3. Coolant leak or true overheating

    Common general cause
    Why it ranks here
    A 2018 CX-9 owner reports a dealer confirming P111A with a coolant leak and cracked head, and a 2019 CX-9 scan showed 251.6 F with limp mode.
    What would change this
    Rises if coolant is low, there is steam or the gauge runs hot. Falls if the engine temperature is normal.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

  1. With the engine cold, check coolant level and look for leaks, and note whether the temperature gauge or warning showed real heat.

    Use cautionTool: flashlight

    Warning:Never open the radiator or reservoir cap on a hot engine. Pressurised coolant can cause severe burns.

    • IfCoolant is low or there are leaks

      It meansTreat it as a real overheating problem and stop driving.

      Points to: Coolant leak or true overheating

    • IfLevel is fine and the warning came on in extreme cold with poor heat

      It meansAsk about the coolant concentration bulletin.

      Go to step 2

    • IfLevel is fine and the fan did not run properly

      It meansAsk about the fan software bulletin.

      Go to step 2

  2. Ask a Mazda dealer whether your VIN has an open bulletin for P111A, and have them test coolant concentration and fan operation.

    Best left to a shopTool: coolant tester, scan tool

    Warning:This needs specialist tools and vehicle service information. Leave it to a shop.

Symptoms

  • High engine temperature warning light Gets more serious: stop and have it checked.
  • Limp mode or reduced power Gets more serious: stop and have it checked.
  • Poor heater output
  • Weak air conditioning
  • Coolant loss

How to fix

Parts and cost context

  • Thermostat:A thermostat or sensor is not the documented fix in the Mazda bulletins; diagnose coolant, fan and software first. Get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Mazda

  • 2014–2015 · Mazda3

    Supported by vehicle data

    Mazda 01-022-15-3083 ties P111A and a high temperature light in extreme cold to the factory coolant concentration. Whether the bulletin is still current is not verified.

  • 2019–2020 · CX-5

    Supported by vehicle data

    Mazda 01-007-20-3691 ties P111A with overheating and weak A/C to cooling fan control software. Whether the bulletin is still current is not verified.

  • 2018–2019 · CX-9

    Supported by vehicle data

    Owners report P111A with limp mode at 251.6 F (2019) and a coolant leak with a cracked cylinder head (2018).

  • 01-022-15-3083Status unverified

    High coolant temperature warning with P111A in extreme cold

    2014–2015mazda3 · NHTSA 10101461

    Names P111A:00 as engine coolant temperature high; the production coolant concentration may not have been set correctly.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • 01-007-20-3691Status unverified

    Overheating and weak A/C with P111A

    2019–2020cx-5 · NHTSA 10174569

    Names P111A:00 as engine coolant temperature high; improper control module software may make the cooling fan run improperly.

    We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

  • P011AThe two engine coolant temperature sensors disagree with each other

    Same system Possible — needs testing

    P011A compares the two coolant sensors, while P111A is the Mazda coolant-too-hot code; both appear in Mazda coolant bulletins.

All Engine cooling (thermostat) codes

P111A questions

Does P111A mean the same on other brands?

We only have a sourced meaning for Mazda. On other makes, treat the code as unverified.

Can I drive with P111A?

Not if the temperature warning is on or the car is in limp mode. Overheating can crack the cylinder head.

Sources and review

  1. Mazda 01-022-15-3083 (NHTSA 10101461): 2014-2015 Mazda3 high coolant temperature warning with P111A — Mazda Motor Corporation
  2. NHTSA complaint ODI 11481366: Mazda CX-9 2018, P111A engine overheated DTC with coolant leak — NHTSA Office of Defects Investigation
  3. NHTSA complaint ODI 11690498: Mazda CX-9 2019, P111A at 251.6 F with limp mode — NHTSA Office of Defects Investigation
  4. Mazda 01-007-20-3691 (NHTSA 10174569): 2019-2020 CX-5 overheating and weak A/C with P111A — Mazda Motor Corporation
Last reviewed
Written by
Saurabh K.
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