my Toyota Corolla E170 (2013-2019) AC only blows hot air, what could be wrong?

Toyota Corolla E170 (2013-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

528 words

Problem Statement

Learn how to diagnose and fix AC blowing hot air in Toyota Corolla E170 (2013-2019). Step-by-step guide with diagnostic procedures and repair instructions.

Affected Component

HVAC

Estimated Time

2-4 hours

⚠️ Safety Warnings

Important safety information - read before proceeding

•Disconnect battery before working on electrical systems.
•Follow proper safety protocols when handling refrigerants.

Symptoms

•Hot air blowing from the AC vents
•AC compressor not engaging
•Unusual noises from the AC system when turned on
•AC system cycling on and off frequently
•Low refrigerant level indicated by pressure gauge (if checked)
•Foul odor or musty smell from AC vents

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for AC system-related faults.
2
Inspect the AC compressor for physical damage or signs of wear.
3
Check the refrigerant level with a pressure gauge to ensure it is within the manufacturer's specifications.
4
Examine the AC system's fuses and relays for any blown fuses or malfunctioning relays.
5
Inspect the cabin air filter for blockage that could restrict airflow.
6
Test the AC pressure switch for proper operation.

Solution

💡 Expert Tip

For complex repairs like this, consider taking photos at each step. This helps if you need to reverse a step or consult with a mechanic. Also, keep all removed parts organized - you may need to reference them during reassembly.

Verification

After completing the repair, verify that the issue has been resolved:

✓Test the affected component to ensure it functions correctly
✓Check for any error codes or warning lights
✓Monitor the vehicle for a few days to ensure the issue does not recur

Prevention Tips

To prevent this issue from occurring again:

•Follow the manufacturer's recommended maintenance schedule
•Address warning signs early before they develop into major issues
•Use quality parts and fluids recommended for your vehicle
•Keep detailed records of all repairs and maintenance

Tools & Equipment Required

•OBD-II scanner
•Refrigerant gauge set
•Basic hand tools (sockets, wrenches)
•Leak detector
•Safety glasses
•Gloves

Parts Required

•R134a refrigerant
•AC compressor (if faulty)
•AC relay (if faulty)

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to check for AC system-related faults.
2
Inspect the AC compressor for physical damage or signs of wear.
3
Check the refrigerant level with a pressure gauge to ensure it is within the manufacturer's specifications.
4
Examine the AC system's fuses and relays for any blown fuses or malfunctioning relays.
5
Inspect the cabin air filter for blockage that could restrict airflow.
6
Test the AC pressure switch for proper operation.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the battery to ensure safety while working on the electrical system.
Wear safety glasses and gloves.

2. Check Refrigerant Level

Connect a refrigerant gauge to the low-pressure service port.
Start the engine and turn the AC to maximum cooling.
Observe the gauge reading; if it’s below the recommended level, proceed to recharge.

3. Recharge the AC System

Use R134a refrigerant compatible with the Toyota Corolla.
Follow the instructions on the refrigerant canister for proper charging methods.
Monitor the pressure gauge during the fill to avoid overcharging.
Once charged, check for any leaks in the system using a leak detector.

4. Inspect and Replace Components

If the compressor is not engaging, test the AC relay by swapping it with a similar relay in the fuse box.
If the compressor is faulty, replace it:
- Disconnect the AC lines from the compressor.
- Remove the mounting bolts and take out the old compressor.
- Install the new compressor and tighten bolts to manufacturer specifications (typically around 15-25 ft-lbs).
- Reconnect the AC lines and ensure they are secure.

5. Final Checks

Reconnect the battery.
Start the engine and turn on the AC to verify proper operation.
Check for any unusual noises or leaks.