P2DA6: Coolant Heater A Over Temperature
Coolant heater A reports temperature above the protection threshold. Coolant flow blocked or thermistor failed.
What P2DA6 means
P2DA6 is a generic OBD-II powertrain code in the cooling group.
- Check engine light
- Usually on
- Emissions-related
- No
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
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Common causes
- 01Coolant flow through heater blockedMost likely
- 02Thermistor failedPossible
Can I drive with P2DA6?
No. Stop and let the engine cool.
If the temperature gauge is high or you see steam, pull over and switch off. Driving an overheating engine can warp the head and blow the head gasket.
Why we rate it urgent
- Engine over-temperature can cause head-gasket and engine damage
- Turns on the check engine light
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose P2DA6
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just P2DA6. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Fix other faults first
If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.
- 3
Check live data
Watch the related sensor and actuator readings in live data (Coolant heater A, Coolant heater A control module) and compare them with expected values in the service information for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Coolant flow through heater blocked; thermistor failed. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
P2DA6 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Moderate
- Good DIY job?
- Usually a shop job
Needs a scan tool and some experience with testing.
Parts and systems involved
- Coolant heater A
- Coolant heater A control module
P2DA6 FAQ
What does P2DA6 mean?
P2DA6 means “Coolant Heater A Over Temperature”. Coolant heater A reports temperature above the protection threshold. Coolant flow blocked or thermistor failed.
Is P2DA6 serious? Can I keep driving?
We rate P2DA6 as urgent severity. No. Stop and let the engine cool. If the temperature gauge is high or you see steam, pull over and switch off. Driving an overheating engine can warp the head and blow the head gasket.
What causes P2DA6?
The most common causes, from most to least likely: Coolant flow through heater blocked; Thermistor failed. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix P2DA6?
Typical labor is about $125–$625 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix P2DA6 myself?
DIY difficulty is moderate. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will P2DA6 clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.