Indoor Pipe Temperature Sensor (TH2) Error

What it means

This code appears on the wired remote of Mitsubishi Electric Mr. Slim ducted, ceiling and cassette units. It means the liquid pipe thermistor on the indoor coil (TH2) is open or shorted. The unit uses this sensor to protect the coil from freezing and to control cooling, so it stops when the reading is lost. The same code can mean something else on other brands, and wall-mounted Mitsubishi Electric models show errors as lamp blinks with a different meaning.

Models covered: Mitsubishi Electric ducted, ceiling and cassette units (Mr. Slim) with check codes on the wired remote; wall-mounted Mitsubishi Electric models may show errors as lamp blinks with a different meaning.

Related codes: P1P6P8

Symptoms4

• The unit stops and P2 shows on the wired remote.
• The code returns right after restart or a few minutes after the compressor starts.
• Weak cooling or ice on the indoor coil before the code in some cases.
• The code appears after the indoor unit was serviced or cleaned.

Possible causes5

• The sensor has slipped off the coil pipe or its connector on the board is loose.
• The TH2 thermistor has failed from constant moisture around the coil.
• The sensor lead was cut or pinched when panels were removed or the coil was cleaned.
• Corroded connector pins from condensate water.
• A fault in the sensor input circuit on the indoor board (less common).

How to diagnose5

1. Switch the unit off at the breaker for a few minutes, restart, and note when the code returns.
2. Check whether the indoor unit was recently serviced or washed, which points to a disturbed connector or lead.
3. With power off, the technician confirms the sensor is seated on the pipe and its connector is sound.
4. The technician measures the sensor resistance, compares it with the manufacturer table at the same temperature, and flexes the lead to find an intermittent break.
5. If the sensor and lead are good, the indoor control board is checked.

How to fix5

1. Refit the sensor on the pipe and reseat its connector.
2. Clean the connector pins or repair the damaged lead.
3. Replace the TH2 thermistor with the correct part for the model.
4. Replace the indoor control board if it is proven faulty.
5. Run the unit in cooling long enough and confirm the code does not return.

Repair cost

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost stays low when a connector or thermistor is the cause, and rises if the indoor unit needs a new control board.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions