Toyota Aqua Hybrid Engine Problem

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Toyota Aqua Hybrid Engine Problem

I’m facing a strange issue with my 2013 Toyota Aqua. Here’s what’s happening:

When I turn off the engine, it shuts down as expected. However, sometimes, after a few seconds, the display screen turns back on automatically. The car doesn’t go into READY mode during this, though. In these instances, I can turn the display off again by pressing the start button. If I press the start button with the brake pedal, the car enters READY mode.

When this happens, I notice some strange behavior with the settings:

The AC temperature resets to 25°C.
The clock resets to 1:00.
The average fuel consumption and speed reset to 0.00.
Only the trip counters retain their previous values.
After servicing the car done by Toyota Lanka, I received a vehicle diagnostic report. According to the report, a DTC Diagnostic Trouble Code B1412 had been recorded and cleared earlier. Additionally, the outside temperature display has never worked since I purchased the vehicle.

This issue has occurred three o r four times so far. Is this normal behavior, o r could there be a problem with the car’s electronics? Should I take it to a knowledgeable technician for further inspection, o r is it something I can safely ignore?

Looking forward to your comments and advice.

Thanks in advance!

Zarnish asked on 24 Jan 2025 11:19:12 am

1 Answer

19 views |

Car Mechanic Expert - on 24 Jan 2025 11:24:45 am

Hi!
This is detailed analysis and advice about the issue with your 2013 Toyota Aqua:
1. Unusual Display Screen Behavior

Possible Causes:
A glitch in the cars electronics o r control module may be causing the display screen to power on unexpectedly.
A weak 12V auxiliary battery can lead to erratic behavior in hybrid vehicles, including screens turning on o r resetting unexpectedly.

Recommendation:
Have the 12V auxiliary battery tested. Even if the battery starts the car, a weak o r failing battery can cause strange electrical issues.
Inspect the power settings o r wiring for the display unit to ensure there are no loose connections o r faults.

2. AC and Clock Resetting

Possible Causes:
The resetting of the AC temperature, clock, and fuel consumption stats indicates that the ECU Electronic Control Unit is losing power intermittently.
This could be due to a failing 12V battery, a faulty connection, o r an issue with the Body Control Module BCM.
DTC B1412 relates to an issue with the solar sensor circuit, which might explain why the outside temperature display isnt working and could point to a related wiring o r sensor problem.

Recommendation:
Ask a technician to check the vehicles ECU and Body Control Module for any signs of faulty wiring o r power loss.
Verify if the solar sensor circuit o r related wiring has been properly inspected o r repaired after the DTC was cleared.

3. DTC Diagnostic Trouble Code B1412

Details:
B1412 refers to the solar sensor circuit malfunction. This sensor is critical for climate control functions, such as adjusting the AC based on sunlight intensity.
A malfunction in this circuit could be linked to the resetting AC temperature and might indicate a broader electrical issue.

Recommendation:
Have a technician inspect the solar sensor and its associated wiring.
Ensure no residual codes o r underlying issues with the climate control system remain.

4. Outside Temperature Display

Issue:
If the outside temperature display has never worked, this points to a likely fault in the temperature sensor o r its connection to the display module.

Recommendation:
Test the temperature sensor and its wiring. A replacement sensor may be required if it is faulty.

5. General Advice

Is This Normal?:
No, this is not normal behavior. The symptoms indicate an underlying electrical o r control module issue that needs attention.

Should You Ignore It?:
Ignoring these issues could lead to more significant problems, especially if the 12V battery o r ECU is involved. It’s best to address them promptly.

Next Steps:
Visit a technician familiar with hybrid systems, preferably a Toyota-certified service center.
Request a thorough inspection of the 12V auxiliary battery, ECU, BCM, and climate control systems.