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Error code reference

Denso Air Conditioner Error Code E1

Room thermistor connection problem

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What the E1 error code actually means

Your Denso air conditioner cannot read the room temperature because the sensor responsible for that measurement has lost its connection or has failed. The unit displays E1 to let you know something is wrong before it continues running. In most cases, unplugging and replugging the sensor connector fixes the problem, but if not, the sensor itself likely needs to be replaced.

Diagnostic procedure

The full E1 procedure

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1
First diagnostic step
Disconnect and reconnect the room thermistor. If it does not work, replace room thermistor.
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Most common causes of E1

Ranked by how often they cause this code
  1. 1Loose or disconnected thermistor connector
  2. 2Failed room thermistor
  3. 3Corroded or damaged connector terminals
  4. 4Damaged wiring harness
  5. 5Control board fault

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Questions people ask about E1

What does E1 mean on a Denso air_conditioner?
E1 on a Denso air conditioner indicates a room thermistor connection problem. The control board has detected that the thermistor circuit is either open (no continuity) or shorted. This prevents the unit from accurately reading room temperature, so it shuts down normal operation and displays the fault code.
Will resetting my Denso air conditioner clear the E1 error?
A power reset alone will not permanently clear E1 if an underlying fault exists. The error will return as soon as the control board re-checks the thermistor circuit. The reset is only effective as a first step combined with physically reconnecting the thermistor, or after the faulty component has been repaired or replaced.
How much does it cost to fix a Denso E1 error?
If the fix is simply reconnecting a loose thermistor plug, there is no parts cost and only minimal labor time involved. If the thermistor itself needs replacement, parts and labor together typically range from around $75 to $200 depending on the specific unit and local service rates. Control board replacement, if required, can push costs considerably higher.
How do I fix the E1 error on my Denso air conditioner?
Start by turning off the unit and disconnecting power, then locate the room thermistor connector on the indoor unit and firmly disconnect and reconnect it. Restore power and check whether the error clears. If E1 returns, test the thermistor itself with a multimeter for an open or shorted condition and replace it if the reading is out of range.
Is it safe to keep running my Denso air conditioner when E1 is displayed?
Running the unit while E1 is active is not recommended. Without a functioning room thermistor, the control board cannot regulate temperature accurately, which can lead to the system operating outside its intended parameters. Most Denso units will restrict or suspend operation automatically when this fault is present.

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