why does my Toyota Corolla E170 (2013-2019) AC only blow hot air?

Toyota Corolla E170 (2013-2019)

Error Codes

2-4 hours

Time

medium

Difficulty

medium

Severity

3 min read

572 words

Problem Statement

Learn how to diagnose and fix the AC blowing hot air issue in your 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 the battery before working on electrical systems.
•Always wear gloves and safety glasses when handling refrigerants.

Symptoms

•AC system blows hot air regardless of temperature settings
•AC compressor not engaging
•Unusual noises when the AC is activated
•Reduced airflow from the vents
•AC warning light illuminated on the dashboard

Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any AC-related fault codes.
2
Check the refrigerant level using a manifold gauge set to determine if the system is undercharged.
3
Inspect the AC compressor visually for signs of damage or leaks.
4
Test the AC relay and fuse to ensure they are functioning properly.
5
Check for blockages in the cabin air filter or ductwork that may affect airflow.
6
Verify the operation of the AC control module and temperature sensors.

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
•Manifold gauge set
•Multimeter
•Basic hand tools (screwdrivers, wrenches)

Parts Required

•R-134a refrigerant
•AC compressor (if faulty)
•AC relay (if faulty)
•Cabin air filter

Related Faults

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Diagnostic Steps

1
Scan for error codes using an OBD-II scanner to identify any AC-related fault codes.
2
Check the refrigerant level using a manifold gauge set to determine if the system is undercharged.
3
Inspect the AC compressor visually for signs of damage or leaks.
4
Test the AC relay and fuse to ensure they are functioning properly.
5
Check for blockages in the cabin air filter or ductwork that may affect airflow.
6
Verify the operation of the AC control module and temperature sensors.

Solution

1. Preparation

Gather necessary tools and parts.
Disconnect the vehicle's battery to ensure safety during repairs.

2. Recharge the AC System

Connect Manifold Gauges: Attach the low and high pressure sides of the manifold gauge set to the AC service ports.
Check Refrigerant Level: Read the gauges to determine the refrigerant level. If low, proceed to recharge.
Recharge the System:
- Use the appropriate refrigerant (R-134a for this model).
- Open the low side valve on the manifold gauge to allow refrigerant to flow into the system.
- Monitor the pressure and ensure it reaches the manufacturer's recommended level.
Disconnect Gauges: After recharging, safely detach the manifold gauges and replace the service port caps.

3. Inspect and Replace Components

Check the AC Compressor: If the compressor is not engaging:
- Inspect the electrical connections for damage.
- Test the compressor clutch with a multimeter for continuity.
- Replace the AC compressor if it is faulty.
Replace AC Relay: If the relay is not functioning, locate the relay box and replace the AC relay with a new one.

4. Clean or Replace Cabin Air Filter

Locate the Cabin Air Filter: Access the cabin air filter compartment, usually behind the glove box.
Inspect Filter: Remove the filter and check for dirt and blockages.
Replace Filter: If dirty, replace it with a new cabin air filter.

5. Reassemble and Test

Reconnect the battery.
Start the vehicle and test the AC system for proper operation.