Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Electronic Automatic Temperature Control (EATC) Module Cold Boot Process
The purpose of the cold boot process is to allow the EATC module to reinitialize and calibrate the actuators. To carry out the cold boot process, follow the steps below.
- Turn the ignition switch to the OFF position.
- Disconnect the EATC module electrical connectors.
- Wait one minute.
- Inspect module connectors for:
- corrosion.
- pushed-out connector pins.
- incorrectly seated connectors.
- Connect the EATC module electrical connectors.
- Turn the ignition switch to the ON position.
- Select any position except OFF on the EATC module.
The EATC module will now initialize and calibrate the actuators. Calibration of the actuators will take approximately 30 seconds.
| DTC | Description | Action to Take |
|---|---|---|
| B2266 | Blend door failure or short | Go to Pinpoint Test A . |
| B1251 | A/C in-vehicle temperature sensor open circuit | Go to Pinpoint Test B . |
| B1253 | A/C in-vehicle temperature sensor short to ground | Go to Pinpoint Test B . |
| B1255 | A/C ambient temperature sensor open circuit | Go to Pinpoint Test C . |
| B1257 | A/C ambient temperature sensor short to ground | Go to Pinpoint Test C . |
| B1259 | A/C solar radiation sensor circuit open | Go to Pinpoint Test D . |
| B1261 | A/C solar radiation sensor circuit short to ground | Go to Pinpoint Test D . |
| B2268 | Steering wheel climate control circuit open | Go to Pinpoint Test R . |
| B2269 | Steering wheel climate control circuit short to ground | Go to Pinpoint Test R . |
| U1073 | SCP invalid or missing data for engine coolant | Refer to INTRODUCTION -- DIESEL ENGINES or INTRODUCTION -- GASOLINE ENGINES article. |
| U1341 | SCP invalid data for vehicle speed | Refer to INTRODUCTION -- DIESEL ENGINES or INTRODUCTION -- GASOLINE ENGINES article. |
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.