ACP Amana High-Speed Oven Error Code C1: Temperature Sensor Shorted

What does ACP Amana error code C1 mean?

The RTD sensor reports cavity temperature as a resistance, and the control expects a value in a normal band. When the sensor circuit is shorted, the resistance collapses, and the control shows C1 as it starts a program. It cannot read the cavity temperature, so it will not heat. Heat and age can break down the insulation on the sensor wire over the years, which lets the conductors touch. The manual also lists an RTD lead pinched against metal inside the oven, a damp or dirty connector at the main board, and a board input that reads the circuit as a short. The owner step is to unplug the oven for a short while and plug it back in after it cools. Tell us whether the code showed the moment a program began or after a few minutes of cooking, because that narrows the cause. Do not poke into the cavity or lift panels. A shorted sensor circuit can come from a pinched wire, which only a technician can trace safely, with a meter and the oven unplugged.

Affected models and control systems

This applies to the Amana Xpress AXP22 and MXP22 touch panel combination ovens, as covered in the ACP Commercial Service and Training Manual. The older AXP20/MXP20 write this reading as C-1.

Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.

What you may notice

• C1 on the display
• The oven will not heat
• The code shows as a program begins
• The code appears again after a restart

Possible causes

Listed in ACP Amana's documentation

• RTD wire insulation aged and broken down
• RTD lead pinched against metal inside the oven
• Connector at the main board damp or dirty
• Main board input reading the RTD as a short

Other likely causes — what usually sits behind error code C1 on this control. A technician confirms which one it is before any part is replaced.

• A sensor lead whose braid has frayed against the cavity wall so it touches ground
• A connector at the main board that is wet from steam and carries current across its pins

Safe checks before calling for service

How a technician diagnoses error code C1

1. Read the code and note when it shows.
2. Trace the RTD lead for pinches and worn insulation.
3. Measure resistance across the sensor and to ground.
4. Inspect the main board connector for damp or dirt.
5. Repair the lead or replace the RTD or board according to the result.

How error code C1 differs from similar codes

C0 is the open reading and C2 the out-of-range reading from this sensor. C1 is the shorted reading.

Technical reference

Document

ACP Commercial Service and Training Manual

Edition

December 2011, 16400012

Models / control

AXP22 / MXP22 (touch panel)

Section

Display Diagnostics - Error Codes: AXP20/MXP20 (hyphenated codes, M-0 to M-2) printed p. 58 (PDF p. 65); AXP22/MXP22 printed p. 74 (PDF p. 81)

Checked

October 2026

We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.