Servicing Honda Civic Hybrid Vehicles

Servicing Honda Civic Hybrid Vehicles

The number one problem with Honda Civic Hybrids has been the high-voltage IMA battery. The first generation cars use a 144-volt nickel metal hydride (NiMH) battery, while second generation cars use a higher voltage 158.4V NiMH battery. Third generation cars use a totally different kind of battery, a Lithium-Ion 158V battery that is about 30% more powerful than that in the previous models.

The Honda Civic Hybrid is now in its third generation. It was introduced to the U.S. market back in 2002 as a model year 2003. The Civic Hybrid was Honda’s answer to the Toyota Prius, and was its second hybrid offering following its two-seat Insight that was introduced in 1999 as a model year 2000.

The first generation Civic Hybrids in the U.S. market are the 2003-’05 models, the second generation cars are the 2006-’11 models, and the third generation started with model year 2012.

The Civic Hybrid models are a different breed of hybrid than the more sophisticated Toyota Prius in that there is only a minimal full-electric mode of operation. Unlike the Prius that can start up and drive on battery power alone for a limited distance and speed, the Civic uses its Integrated Motor Assist (IMA) system primarily to boost engine power when extra oomph is needed to accelerate, pass or climb a hill.

The electric motor produces only 13 hp in the first generation Civics, 20 hp in the second generation models and 23 hp in the third generation, so the amount of assist isn’t that much. The gasoline engine, by comparison, makes 85 hp in the first generation Civics, and 93 hp in the second and third generation cars, so most of the power that drives the car comes from the gasoline engine, not the IMA electric motor.

The IMA electric motor is attached to the engine’s flywheel, so the engine has to be turning for the electric motor to contribute power to the drivetrain (unlike a Prius, which can decouple its electric motors from the engine). Consequently, there is no start-up electric-only mode of operation in a Civic Hybrid as there is with a Prius.

However, on the second and third generation Civic ­Hybrids, there is a full electric mode that may occur briefly depending on the charge level of the IMA battery while cruising under light load between 15 and 20 mph. When this happens, the engine’s cylinders are temporarily deactivated and the car is propelled by battery power alone to save fuel.

The first- and second-generation Civic Hybrids are powered by a 1.3L VTEC engine that can deactivate three cylinders (first generation) or all four cylinders (second generation) during decel to save fuel. The third generation cars get a larger 1.5L VTEC engine, but the power output is the same as the previous models.


The number one problem with Honda Civic Hybrids has been the high-voltage IMA battery. The first generation cars use a 144-volt nickel metal hydride (NiMH) battery, while second generation cars use a higher voltage 158.4V NiMH battery. Third generation cars use a totally different kind of battery, a Lithium-Ion 158V battery that is about 30% more powerful than that in the previous models.

The problem with the first and second generation batteries is that they can fail prematurely for a variety of reasons. Undercharging is one, and overheating is another. According to some sources, average battery life in these vehicles is only about seven years, and the second generation cars are worse than the first.

For the high-voltage IMA battery to last, it must be kept at or above a 50-60% State of Charge (SOC) most of the time. That means driving the car frequently enough to keep the battery charged (at least once every month). If the car sits for more than a month in extreme conditions like heat, the battery may get so low that it never fully recovers and eventually fails. What’s more, if the battery sits fully charged (over charged 80% SOC plus) for more than 90 days, it will often fail within a matter of months.

According to one report in the Los Angeles Times, more than 4% of the high-voltage batteries in 2006-’08 Honda Civic Hybrids have been replaced — a figure that’s unacceptably high according to the California Bureau of Auto Repair.

Many of the premature battery failure problems have been blamed on the driving habits of the vehicle owners: not driving the cars often enough or far enough to keep the battery fully charged. To address this issue, Honda came out with a software update to extend battery life. Honda blames its premature battery failure problem on “frequent stop-and-go city driving with the A/C on, especially during warm weather. This type of driving can leave the IMA battery in a low state of charge. Over time, this can cause battery deterioration and failure.”

The Honda TSB software update (09-058 and more recently 10-034) essentially “detunes” the IMA system so it uses assist less often, and, thus, puts less load and stress on the battery. Some Civic owners have complained that their cars feel more sluggish or don’t get the same mileage after they’ve had the control software updated (which actually involves ­reflashing the IMA battery software, the PGM-FI engine control software and the CVT transmission software).

If an IMA battery fails, it’s expensive to replace. Honda dealers are reportedly charging $3,000 to as much as $4,000 to replace batteries that are not covered by warranty — which is another issue in itself.


Courtesy of Craig Van Batenburg, ACDC, Worcester, MA.

Civic owners who have had a hybrid battery call it quits have frequently encountered confusing and misleading information about their battery’s warranty coverage. We looked into this issue and found that basically the battery’s warranty coverage will vary depending on the emissions certification of the vehicle, the state where it was originally registered, its VIN number, and its age and mileage since it was manufactured.

In California and other states that have similar SULEV and PZEV emission rules (which includes CA, NY, VT, ME, MA, RI and CT, plus NJ, OR, WA, PA, NM and FL since 2010), the IMA battery warranty is 10 years or 150,000 miles. On the third generation vehicles, Honda says the battery warranty in these states is 15 years or 150,000 miles. For every other state, the battery warranty is eight years or 80,000 miles, whichever comes first.

If a failed battery is still under warranty, Honda will replace it at no cost to the owner. If the battery is out of warranty, Honda sells a “refurbished” battery for around $2,200 plus installation (which comes with a one-year warranty) or a new battery for around $3,000 plus installation (which comes with a three-year warranty). Aftermarket refurbished batteries are also available for around $1,700 to $2,200 (plus the car’s old battery) from sources such as or

Most hybrid experts caution against replacing a dead battery with one from a salvage yard because chances are a used battery has been sitting in a discharged state for a long time and won’t last if it’s returned to service. The problem is that some NiMH cells discharge at a different rate than others. This upsets the internal charge balance of the battery and prevents the battery from recharging normally, which will eventually cause it to fail.


Honda’s self-diagnostics cover the IMA system pretty well, and will usually detect most problems in the IMA system or battery. When such a fault occurs, the system will set a fault code and turn on the IMA warning light. So, if the IMA warning light is illuminated on a customer’s car, plug in a scan tool to find out what’s the matter. Some aftermarket scan tools can display IMA fault codes, but others may not have all of the codes or be capable of accessing all of the system data or self-tests.

Craig Van Batenburg of ACDC Hybrid training ( recommends using a Honda scan tool for diagnostics, such as the Vetronix Mastertech for 2003 models, or a Teradyne scan tool for 2004 and later models.

Any of the following codes usually means the car needs a new battery: P0A7E, P0A7F, P1435, P1446 or P1570. Other battery-related codes include: P1447, P1449, P0A9D, P0A9E, P0AC7, P0ACD, P1574, P0A27 and P0AE1. These codes indicate battery-related faults that may or may not require replacing the battery.

If you’re clearing codes with an aftermarket scan tool, Van Batenburg says the 2003 Honda Civic Hybrids have a quirk that requires you to clear the codes twice before the IMA warning light will stay off. He also said these models may have P1440 and P1679 codes, which are false codes and can be ignored.

If the hybrid battery in a Civic is discharged, Van Batenburg offers the following advice for recharging it (since no high-voltage battery charger is available for such purposes): Just start the car and let the engine recharge the battery. Remove the #15 fuse from the underhood fuse panel and run the engine at 3,000 rpm to fast-charge the battery. When all of the status bars on the dash charge indicator are illuminated, the battery is fully charged.

Something else to keep in mind about the Civic Hybrid is that it has a conventional 12-volt starter as a backup in case there is a failure with the high-voltage IMA system. If the IMA battery has sufficient charge, the IMA electric motor on the flywheel will start the engine, otherwise the conventional 12V starter will kick in to crank the engine to life. The 12V starter is also used in extreme cold.

The high-voltage hybrid battery can be dangerous because of the potential shock hazard. There is one Honda-approved way to disable the high-voltage IMA system. Turn off the ignition and disconnect the negative ground cable from the conventional 12-volt battery in the engine compartment. This will disable the IMA controller and prevent it from routing high voltage into the IMA system.

Then, remove the back seat, remove the small switch cover on the battery pack and turn off the switch (down). Wait at least five minutes for the system’s high-voltage capacitors to discharge before working on the battery or other IMA high-voltage components.

If any work needs to be done on the hybrid battery junction board or control module, wear insulated gloves and use insulated tools.

For normal maintenance and repairs to non-IMA system components, there’s no need to disconnect the hybrid battery or disable the IMA system. Just make sure the ignition is off. Even so, avoid touching any orange-color-coded, high-voltage cables.


Hybrid battery on/off switch. Courtesy of Craig Van Batenburg, ACDC, Worcester, MA.

There have been few problems with the IMA electric motor on the back of the engine, but if you have to pull one you’ll need a special $700 puller to get it off.

The engine in the Civic Hybrid requires 0W-20 motor oil. If a heavier-viscosity motor oil is used, it may adversely affect the operation of the VTEC valve control system. Not changing the oil often enough can also foul the VTEC valve control system and set a P1259 code.

On first generation Civic Hybrids, the oil filter needs to be prefilled with oil before it’s installed. Most technicians don’t take the time to do this, but not filling it can allow air to be pumped into the VTEC control system, causing a P1021 code to be set.

Another common code on these cars is a P1491 EGR code. This can be caused by a buildup of carbon under the engine’s EGR valve. Cleaning the EGR port every 60,000 to 90,000 miles will prevent this from happening.

The Continuously Variable Transmission (CVT) requires a special Honda fluid, and also requires a special relearn driving procedure if the battery has been disconnected or replaced.

Van Batenburg says if a Civic Hybrid is experiencing a driveability problem and you’re not sure if it’s the gas engine or the IMA system, remove the IMA fuse and drive the car in gas-only mode. If the problem goes away, the fault is in the IMA system. If the fault is still there, it’s in the gas engine control system.

On the second and third generation Civic Hybrids, a combination belt/electric drive A/C compressor is used. It requires a special insulating compressor oil: Sanden SE-10Y (P/N 38899-RCJ-A01). The A/C compressor works in conjunction with the engine’s idle stop system to keep the A/C going if the engine shuts off when the vehicle is stopped. Normally, the engine stop system will kill the engine momentarily when the vehicle comes to a halt after being driven at 7 mph or faster.

However, the idle stop system won’t kill the engine if the car is suddenly braked (panic stop), when the engine temperature is too low (cold engine), when the defrosters are on, when there are high electrical loads on the system, when ambient temperatures are too high and the A/C is running on the fourth or fifth high-speed setting, when the hybrid battery is too low, or when any IMA-related faults are present.


The Civic Hybrids are equipped with Antilock Brakes (ABS) and Traction Control (TC), as well as Electronic Brake Distribution (EBD) to shift more braking effort to the rear brakes. EBD reduces stopping distances but also increases rear brake lining wear, requiring more frequent replacement of the rear brakes.

In 2009, the Civic Hybrids got Vehicle Stability Assist (VSA). The VSA system helps counter oversteer and understeer by braking either the inside or outside wheels using pressure from the ABS pump. The VSA inputs come from the wheel speed sensors, brake pedal, yaw sensor (which monitors body motions) and a steering angle sensor (which monitors the driver’s steering inputs). Problems are limited mostly to faulty wheel speed sensor signals (often due to wiring faults). A WSS fault will set a code and disable the VSA/ABS/TC/EBD systems since all rely on WSS inputs for accurate control.

Honda TSB 09-005 (Feb. 6, 2009) reports that a thump, pop or clunk noise from the rear suspension when driving over bumps may be caused by a loose bump stop on one or both rear shock absorbers. The problem can be diagnosed by squeezing the rubber dust boot around the rear shocks. If the bump stop has come loose and slides down, you’ll feel it inside the dust boot. The fix is to replace both rear shocks.

Another brake problem reported on the 2006-’08 Civic Hybrids is a short buzzing sound that occurs when the brakes are applied. The noise is coming from the ­hydraulic booster. Honda TSB 08-057 (Sept. 26, 2008) says the fix is to replace the master cylinder servo assembly, P/N 01469-SNC-315.

Uneven or rapid rear tire wear on 2006-’07 Civic Hybrids can be caused by rear wheel misalignment. Honda recommends installing a rear upper control arm kit, P/N 04523-SNA-A01, to reduce play in the rear suspension, and to adjust rear camber to -1.5 to zero degrees, and rear toe to 2 mm.

You May Also Like

Jump Starting an EV

If an EV with a full battery won’t start, here’s how you can get it up and running.

Here’s a real-world scenario: A customer brings their EV into your shop for service, and it’s been there for quite a while because the parts are on backorder. After a few weeks, you get in the vehicle to move it out of your way, and the ignition won’t turn on. It’s acting like the battery is dead, so what do you do now?

Repairing Wiring Harnesses

A guide to probing and poking.

Diesel Air Filter Replacement

Here are some diesel air filter replacement tips in order to keep these vehicles running as intended.

Diesel Turbocharging Basics

There’s a reason diesels typically utilize compound turbo setups instead of twin turbochargers.

Batteries For Stop/Start Systems

On all stop/start vehicles, the life and performance of the battery are measured by the vehicle in several ways.

Other Posts
EV Opportunities

You are gaining and retaining many service opportunities with Evs.

Toyota Invests Big In Batteries

With an $8 billion investment, Toyota plans for 10 new BEV/PHEV battery lines by 2030.

Selling Underhood Parts for Hybrids

Anything that can happen to an ICE in a standard vehicle can happen in a hybrid.

Toyota Adopts Tesla Charging Standard For Future EVs

With NACS, customers will have access to more charging options, especially DC fast chargers, says Toyota.