OBD-II Code P1449
Battery Module Deterioration (Honda IMA)
P1449 is Honda's primary IMA (Integrated Motor Assist) battery deterioration code and the most common fault code on Honda hybrid vehicles of this era. Honda's IMA system is a mild hybrid architecture — the electric motor assists the petrol engine but cannot drive the vehicle independently. The IMA battery is a NiMH pack (typically 144V in Civic Hybrid and Insight) with 20 modules in most configurations. Honda's Battery Management Module (BMM) monitors individual module voltages and temperatures. P1449 is stored when the BMM determines that one or more modules have deteriorated below the acceptable threshold for reliable IMA operation. Unlike Toyota's system, Honda's IMA controller makes several attempts to 'recalibrate' a weak battery before storing P1449 permanently — drivers sometimes notice the IMA system behaving erratically for weeks or months before the code stores.
At a Glance
Fault Code
P1449
Affects
Honda Civic Hybrid (2003–2011), Honda Insight Gen 2 (2010–2014), Honda Accord Hybrid (2005–2011), Honda CR-Z (2011–2015)
Can You Drive?
Drive with caution
Typical Cost (BC)
$1,299–$1,599 for IMA battery replacement (model dependent)
What Causes P1449?
- 1NiMH module deterioration — same root cause as Toyota hybrid batteries but IMA-specific threshold
- 2Honda's IMA-specific deep discharge protection failure — if battery drops too low during regeneration, P1449 stores
- 3Inconsistent charging from a failing 12V battery affecting IMA system initialisation
- 4Extreme cold weather causing IMA battery to drop below minimum operating temperature
- 5High-mileage use — most IMA systems showing P1449 are on vehicles with 150,000–250,000 km
Symptoms You May Notice
- Orange 'IMA' warning light illuminated on the instrument cluster — distinct from the engine light
- Check engine light appearing simultaneously with the IMA light
- Idle Stop (auto-stop at traffic lights) no longer functioning
- Loss of fuel economy — IMA-equipped vehicles typically return 6–7 L/100km; failing IMA may push this to 9–10 L/100km
- Engine running louder or at higher RPM than expected — all propulsion by engine alone
- Battery charge bars in instrument cluster staying consistently low or fluctuating erratically
Can You Drive with P1449? — Drive with caution
Yes. When P1449 is active, Honda's IMA system disables electric motor assist but the petrol engine continues to operate normally. The vehicle can be driven safely, but fuel economy will be noticeably worse and the engine works harder. The IMA light will not extinguish until the battery is addressed. Do not attempt to reset or ignore the code — continued operation with a severely degraded IMA battery can affect 12V charging system performance.
How It's Diagnosed
- 1
Honda-specific OBD-II scan to confirm P1449 and check for accompanying IMA sub-codes
- 2
IMA battery module voltage testing across all modules
- 3
Battery temperature sensor function check
- 4
12V auxiliary battery voltage test — weak 12V battery is a common co-contributor to IMA faults
- 5
IMA battery current sensor calibration check
- 6
Assessment of whether recalibration or replacement is the appropriate response
How It's Fixed
P1449 on Honda IMA vehicles most commonly requires IMA battery replacement. Unlike Toyota hybrids where reconditioning rarely offers long-term results by the time a code stores, Honda IMA packs in some cases respond to a forced reconditioning process (deep discharge and recharge cycle) that clears the code temporarily — Honda even implemented this automatically in a software update (known as the 'recalibration' TSB) for the Civic Hybrid. However, the effect is typically temporary and most customers with P1449 ultimately proceed to battery replacement for a lasting fix. We stock IMA packs for Honda Civic Hybrid, Insight, and Accord Hybrid.
Typical cost in BC
$1,299–$1,599 for IMA battery replacement (model dependent)
Prices include parts and labour. Contact us for a firm quote on your specific vehicle.
Vehicles Affected by P1449
Frequently Asked Questions — P1449
The IMA (Integrated Motor Assist) light is Honda's dedicated warning indicator for the hybrid battery and motor assist system — separate from the engine check light. When both the IMA light and check engine light are on together, it almost always indicates an IMA battery fault. The IMA light alone (without CEL) is less common and may indicate a different IMA system fault.
Honda's IMA recalibration software update changes how the BMS charges and discharges the battery in an attempt to improve module balance and defer P1449. It works for some vehicles, temporarily for others, and not at all for vehicles with severely degraded modules. If P1449 has returned after a recalibration, the battery modules have degraded beyond what software can compensate for. Replacement is the appropriate next step.
No. Honda's IMA battery is a different pack design — different voltage (144V for most IMA systems vs. 201.6V for Prius), different module configuration, and a different BMS architecture. Honda's IMA is also a mild hybrid system — the motor assists but cannot drive the vehicle alone — which is fundamentally different from Toyota's full hybrid system. Parts and repair procedures are entirely different.
Got a P1449Code? Let's Fix It.
We diagnose and repair P1449 on Honda hybrids in Kelowna and across the Okanagan. Mobile service available — we can come to you.