How to clear IMA light?

The IMA warning light on Honda hybrids usually cannot be cleared by a simple reset; it signals a fault in the Integrated Motor Assist system that needs diagnosis and repair. If you see it, plan a diagnostic check with an OBD-II scanner or a visit to a qualified technician.

The following explainer outlines what the light means, common causes technicians see, how it’s diagnosed, and the proper steps to take to clear the warning after addressing the underlying problem. It emphasizes safety and professional diagnosis rather than simply “resetting” the light.

What the IMA light means

The Integrated Motor Assist system combines a gasoline engine with an electric motor to improve efficiency and performance. The IMA light can illuminate for issues ranging from battery health to cooling, wiring, or control software. When the light is on, the car may run normally, enter a degraded mode, or show reduced power, depending on the fault. In all cases, the root cause should be diagnosed and repaired rather than ignored.

Common causes of the IMA warning

Diagnosing the IMA warning typically starts with examining the most frequent culprits. The list below highlights issues technicians commonly encounter with failing or borderline IMA components.

• Weak or failing high-voltage IMA battery pack or degraded cell balance


• Overheating or insufficient cooling for the IMA battery or inverter



• Faulty IMA control module, sensors, or wiring harnesses


• Software glitches or incorrect calibrations in the hybrid control unit


• Damage or wear in related components such as the inverter, dc-dc converter, or cooling fans

These are common, but not exhaustive, causes. A diagnostic scan will point to the exact fault code or area that needs service.

Diagnosing the IMA warning

Accurate diagnosis hinges on reading fault codes and inspecting relevant subsystems. The steps below describe a typical diagnostic workflow used by technicians.

1. Connect a capable OBD-II scanner or Honda-specific diagnostic tool to read IMA/hybrid system codes. Note any fault codes related to the battery, inverter, or related sensors.


2. Inspect the 12-volt starting battery and its connections for voltage, corrosion, and loose ground straps, since a weak 12V battery can affect hybrid systems.


3. Check the high-voltage battery cooling system, coolant levels, pumps, and heat exchangers to ensure proper temperature management.


4. Evaluate wiring harnesses and connectors for damage, wear, or loose connections in the IMA circuit.


5. Review service history for prior IMA-related repairs, recalls, or software updates that may affect the system.


6. Determine whether the fault is mechanical (battery, inverter) or electrical/software (sensor, wiring, ECU) to guide repair decisions.

After completing the diagnostic steps, the technician will confirm the fault and perform the necessary repairs before attempting to clear codes. If the fault persists, the light will likely return or a service interval may be needed.

Clearing codes and aftercare

Once the underlying fault has been addressed, codes can be cleared to reset the IMA warning. The following steps describe a typical process observed by technicians.

1. Verify that the repair or replacement has been completed and the fault is resolved (no active codes, proper sensor readings, and normal temperatures).


2. Use a compatible diagnostic tool to clear the IMA/hybrid fault codes from the control modules.


3. Perform a limited drive cycle to allow the system to relearn normal operating conditions for the IMA and battery.


4. Monitor the system for a return of the light during initial driving; if the warning reappears, recheck the suspected fault area and consider further diagnosis or component replacement.


5. Document the service and, if applicable, update or reflash the vehicle’s software as recommended by the manufacturer.

Clearing codes is only a part of the process; the light will reappear if the fault is not fully resolved. Ongoing monitoring and test driving are essential to ensure the IMA system operates reliably.

Safety considerations and when to seek professional help

Because the IMA system involves high-voltage components, handling it safely is essential. If you notice burning smells, smoke, unusual noises, or the vehicle fails to start, stop driving and seek professional assistance. Routine diagnosis and minor repairs can typically be performed by trained technicians or a dealership with hybrid experience.

Before attempting any DIY steps, consider the potential risks to both you and the vehicle. A properly trained technician with the right tools can diagnose, repair, and clear the IMA warning more reliably and safely than a home approach.

Summary

The IMA warning light signals a fault within Honda’s Integrated Motor Assist system. It cannot be reliably cleared without addressing the underlying problem. Begin with a diagnostic scan to identify fault codes, inspect the high-voltage battery, inverter, cooling system, and related wiring, and perform the recommended repairs. After fixing the cause, use the diagnostic tool to clear codes and conduct a careful drive cycle to ensure proper re-learning. If the light returns, further professional diagnosis is required. Safety and professional service are advised for any high-voltage hybrid system work.

What causes the IMA light to come on?

The IMA (Integrated Motor Assist) light on a Honda hybrid vehicle comes on to indicate a fault in the hybrid system, most commonly a problem with the hybrid battery pack. Other causes include issues with the 12-volt auxiliary battery, faulty wiring or sensors, or problems with the power inverter. The light signals that performance may be reduced and professional diagnosis is needed to prevent more severe issues.
 
Common causes of the IMA light

• Hybrid battery failure: This is the most frequent cause, where the high-voltage battery pack degrades over time. This can lead to decreased performance, reduced fuel efficiency, and a higher risk of total power loss. 
• 12-volt auxiliary battery: A weak or failing 12-volt battery can cause the IMA system to malfunction, as it powers the hybrid control module. 
• Wiring and sensor faults: Corroded or loose connections, as well as faulty sensors or wiring harnesses in the IMA system, can trigger the light. 
• Power inverter issues: A failing power inverter is a costly repair that can also cause the IMA light to turn on. 
• Control module or software problems: Issues with the hybrid control module or outdated software can also be the root cause. 

What to do when the IMA light comes on

1. Do not ignore it: The IMA light indicates a fault that needs to be addressed. While the car may still be drivable, performance will likely be affected, and further damage could occur. 
2. Have the system scanned: A professional diagnostic scanner can read specific Diagnostic Trouble Codes (DTCs) from the hybrid control module, which will help pinpoint the problem. 
3. Check the 12V battery: Before concluding it's the expensive hybrid battery, have a mechanic check the 12-volt auxiliary battery and related fuses. 
4. Inspect connections: A mechanic can inspect wiring and connectors for corrosion or damage, especially around the battery and inverter. 
5. Consider professional diagnosis: Because of the complexity of the hybrid system, a qualified mechanic or hybrid specialist can perform a thorough diagnosis and recommend the correct repair, which could range from a simple fix to a battery or inverter replacement. 

How to reset IMA light Honda Insight?

To reset the Honda Insight IMA light, check and replace any blown hybrid system fuses, and ensure the 12V battery terminals are clean and secure. If the light remains on after checking these, the issue is likely a more serious hybrid battery problem, requiring professional diagnosis with a specialized scan tool. 
Quick fixes and checks

• Check fuses: Locate and inspect the hybrid system fuses in the under-hood fuse box. Replace any that are blown. 
• Inspect 12V battery: Ensure the 12V auxiliary battery is charged and that its terminals are clean and making a secure connection. 
• Reset code: After addressing any blown fuses or poor connections, you can try turning the vehicle off and on again to see if the light has cleared. 

This video demonstrates how to reset the IMA light on a G1 Honda Insight by removing a fuse: 57sGenXJeffYouTube · Dec 28, 2023
When to seek professional help

• After basic checks: If the light is still on, the problem is likely more significant than a simple fuse or connection issue. 
• Scan tool diagnosis: A professional can use a specialized scan tool to read the specific hybrid system fault codes, which will indicate the exact problem. 
• Potential battery issue: A persistent IMA light often points to hybrid battery degradation or other hybrid system faults that require professional attention. 

Can I drive with the IMA light on?

Technically speaking, you can drive your Honda with the IMA light on. However, driving with the IMA light on increases your risk of damage to the vehicle. If you are unsure of what is wrong with your car or battery, or if you've never worked on one before, it is best to get it looked at by a professional.

How do I reset my emission control light?

You can reset an emission control system warning light by manually disconnecting the car battery or by using an OBD-II scanner. The most common cause is a loose gas cap, so always check that first before attempting a reset. For a permanent fix, you must address the underlying issue; the warning light will likely return if you don't. 
Method 1: Use an OBD-II scanner 

1. Plug the scanner into the OBD-II port, which is usually under the dashboard.
2. Turn the ignition to the "On" position without starting the engine.
3. Use the scanner to read the error codes, which will help you understand the problem.
4. After addressing the issue, use the scanner's "Clear Codes" or "Reset" function to turn off the light. 

This video demonstrates how to use an OBD-II scanner to reset a check engine light: 55sSimpleNick - Nick CollinsYouTube · Jan 22, 2017
Method 2: Disconnect the battery 

1. Locate the car battery under the hood. 
2. Using a wrench, loosen the bolt on the negative (-) terminal clamp. 
3. Carefully remove the negative cable and set it aside, ensuring it doesn't touch the battery or other metal parts. 
4. Hold the horn or turn on the headlights for about 30 seconds to drain any residual power from the system. 
5. Reconnect the negative cable and tighten the bolt securely. 

Method 3: Drive the vehicle 

• In some cases, the light will go off on its own after the issue is fixed and the vehicle has completed a "drive cycle" (approximately 10-100 miles). 
• If the light remains on after a few drive cycles, there is still an issue that needs to be addressed. 

Important considerations

• Check the gas cap first: A loose or faulty fuel cap is a very common and simple cause of this warning light. 
• Diagnose the problem: Do not just clear the light without finding out why it came on. Resetting the light is a temporary fix and will not solve the underlying problem. 
• Consult a professional: If you don't have an OBD-II scanner or if the light returns after you've tried to fix the issue, it's best to consult a mechanic to prevent further damage. 

This video explains what causes the check emission system light to turn on: 1mFixITYouTube · Apr 6, 2025