When your 2016 Honda CR-Z displays an IMA (Integrated Motor Assist) system check message, the sporty hybrid's electric assist system has detected a fault requiring attention. As the final model year for the CR-Z, understanding common issues helps maintain this unique vehicle.
CR-Z Hybrid System Overview
The CR-Z combines a 1.5-liter i-VTEC gasoline engine with Honda's IMA electric motor assist system. Unlike full hybrids, the CR-Z cannot drive on electric power alone—the IMA motor provides supplemental torque during acceleration and captures energy during braking. The lithium-ion battery pack (upgraded from NiMH in earlier CR-Zs) powers the assist motor and stores regenerated energy.
Common IMA System Check Causes
The lithium-ion battery pack, while more reliable than NiMH, can still develop cell imbalances or degradation. The IMA motor or its controller may fail. The 12V auxiliary battery significantly impacts IMA operation—a weak 12V battery causes erratic behavior and warnings. Software glitches sometimes trigger false warnings. The IPU (Intelligent Power Unit) cooling system maintains battery temperature—fan failure or blocked vents can cause issues.
Initial Troubleshooting
Start with the 12V battery—test its charge level and health. A battery past its service life often causes IMA symptoms without being obviously dead. Check the IPU cooling vents (typically behind the rear seats) for blockage. Note any patterns: does the warning appear when hot or cold, during acceleration or braking? Try disconnecting the 12V battery for 15 minutes to reset the IMA system—this clears some software glitches.
Professional Diagnosis
The IMA system requires Honda-specific diagnostic equipment to properly assess. The dealer can read individual battery cell voltages, motor controller status, and historical fault data. Independent shops specializing in Honda hybrids often have equivalent diagnostic capability. Full diagnosis typically reveals whether the issue is battery-related, motor-related, or controller-related.
Repair Costs
12V battery replacement is straightforward at $150-$250. IMA battery pack replacement from Honda costs $2,500-$3,500; refurbished batteries are available for $1,200-$2,000. IMA motor failures are less common but expensive at $1,500-$2,500. Controller replacement runs $800-$1,500. For a 2016 CR-Z, the vehicle's collector potential may factor into whether extensive repairs make sense versus parting ways with the vehicle.