MajorCommonElectrical

Honda CR-Z: IMA battery voltage sag triggering dual warning lights

IMA battery voltage sag triggering dual warning lights is a common electrical fault on the Honda CR-Z on the 2010–2016 cars, and we rate it major. Putting it right costs $1,500 to $5,000 at New Zealand independent workshop rates. Below is what goes wrong, the symptoms to notice on a test drive, where to look, and what to ask the seller before you hand over any money. It is one of 15 documented faults on the Honda CR-Z.

Vehicle: Honda CR-Z
Years: 2010–2016
Fuel: hybrid
System: Electrical

This page covers the Honda CR-Z as a model. Some faults only affect particular engines or build years — enter a plate below to narrow the list to one car.

All Honda CR-Z faults15 documented faults on this model

What you are looking at

No photograph available

We do not hold a verified photograph for this fault yet. We would rather show none than show a picture of something else.

What goes wrong

Under sustained high-load demand such as motorway overtaking or steep hill climbing, degraded IMA battery modules experience acute voltage sag below the threshold required for stable hybrid system operation. This causes both the check engine light and IMA warning light to illuminate simultaneously. Stored fault codes typically include P1600 and P1576 relating to battery module under-voltage events. The check engine light appears because the hybrid system enters a protective reduced-output mode that affects emission-related parameters. Individual module replacement or full pack reconditioning is required to resolve the condition.

What you would notice

Check engine light and IMA warning light illuminated simultaneously
Sudden loss of electric motor assist during motorway acceleration
IMA assist cutting out on uphill grades under sustained load
DTC codes P1600 or P1576 stored in ECU
IMA charge gauge dropping rapidly under load

How to check it

Where to look. IMA battery modules in rear cargo area, battery management system wiring

Scan for IMA-specific fault codes using Honda HDS or compatible scanner.
Request a battery load test and individual module voltage check across all 20 modules.
Confirm whether both lights appear together under hard acceleration or uphill driving.

What it costs to put right

$1,500 to $5,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

Ask the seller

“Have both the check engine and IMA lights ever come on at the same time?”
“Has the vehicle been diagnosed for IMA fault codes P1600 or P1576?”
“Does electric motor assist remain available consistently on motorway driving?”

Now check the Honda CR-Z you are actually looking at

Everything above is true of the model, and it is free. What it does not tell you is whether THIS car has been looked after: its odometer history and whether the reading has ever gone backwards, whether there is still money owing on it, whether it has been reported stolen, how many owners it has had and what it is really worth today. That comes from the official records for that plate. Enter the plate for the free details, or get the full history and a market valuation from $13.49.

Not sure what you would be paying for? See what a full KickTyres check includes.

Where this comes from

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.

Honda CR-Z buyer questions

Is ima battery voltage sag triggering dual warning lights serious on a Honda CR-Z?

We rate it major and common on the Honda CR-Z. Under sustained high-load demand such as motorway overtaking or steep hill climbing, degraded IMA battery modules experience acute voltage sag below the threshold required for stable hybrid system operation. This causes both the check engine light and IMA warning light to illuminate simultaneously. Stored fault codes typically include P1600 and P1576 relating to battery module under-voltage events. The check engine light appears because the hybrid system enters a protective reduced-output mode that affects emission-related parameters. Individual module replacement or full pack reconditioning is required to resolve the condition.

How much does it cost to fix on a Honda CR-Z?

$1,500 to $5,000 at New Zealand independent workshop rates. That figure is for this job on its own. A car showing the symptoms on this page is usually worth either walking away from or negotiating down by at least the repair figure.

Which Honda CR-Z years are affected?

Our research records this fault on the 2010–2016 Honda CR-Z. Build dates move around, especially on imported cars, so treat the range as the years to look hardest at rather than a guarantee either way. The official records tell you the exact build and first registration date for the car in front of you.

How do I check for it before I buy?

Scan for IMA-specific fault codes using Honda HDS or compatible scanner. Request a battery load test and individual module voltage check across all 20 modules. Confirm whether both lights appear together under hard acceleration or uphill driving. Look here: IMA battery modules in rear cargo area, battery management system wiring