Faulty fuel injector or ignition coil within the affected power stage group; Damaged or corroded wiring harness or connector at the actuator; Open or short circuit in the control wire between the ECM and the actuator; Internal failure of the ECM driver for power stage group 'A'; Poor ground connection for the actuator or ECM; Aftermarket or incorrect replacement components causing excessive current draw

DTC codes / Kia codes / P1665

P1665 · KiaPower Stage Group 'A'

Q: What does code P1665 mean?

Power Stage Group 'A'. P1665 on a Kia indicates that the engine control module (ECM) has detected a fault within the power stage group 'A', which is the output driver circuitry responsible for operating a specific group of actuators such as fuel injectors or ignition coils. The ECM monitors the electrical feedback from these circuits and sets the code when the current or voltage falls outside the expected range, signaling an open, short, or driver failure.

P1665 on a Kia indicates that the engine control module (ECM) has detected a fault within the power stage group 'A', which is the output driver circuitry responsible for operating a specific group of actuators such as fuel injectors or ignition coils. The ECM monitors the electrical feedback from these circuits and sets the code when the current or voltage falls outside the expected range, signaling an open, short, or driver failure.

SystemPowertrain

Code typeKia specific

SeverityMedium

Fix difficultyProfessional

AreaComputer and output circuits

Symptoms you may notice

Illuminated check engine light, often with no other noticeable symptoms
Engine misfire or rough running, especially under load or acceleration
Reduced engine power or limp mode engagement
Poor fuel economy or increased emissions
Difficulty starting or intermittent stalling
Audible clicking or ticking from the engine bay if an injector or coil is shorted

Common causes, most likely first

Faulty fuel injector or ignition coil within the affected power stage group
Damaged or corroded wiring harness or connector at the actuator
Open or short circuit in the control wire between the ECM and the actuator
Internal failure of the ECM driver for power stage group 'A'
Poor ground connection for the actuator or ECM
Aftermarket or incorrect replacement components causing excessive current draw

How to diagnose and fix it

Connect a scan tool and record all stored and pending codes, then clear codes and test-drive to confirm P1665 returns
Inspect the wiring harness and connectors for the actuators in power stage group 'A' for chafing, corrosion, or loose pins
Measure resistance of each injector or ignition coil in the group and compare to factory specifications
Perform a current draw test on each actuator circuit to identify excessive or zero current
Check for short to ground or power on the control wires using a multimeter with the ECM disconnected
Substitute a known-good actuator one at a time to isolate the faulty component
If all external components and wiring test good, diagnose the ECM driver circuit or replace the ECM as a last resort

What most technicians overlook with P1665

A single shorted injector or coil can disable the entire power stage group, causing multiple cylinder misfires that mimic a mechanical engine fault.
The ECM driver often fails due to a shorted actuator, so replacing only the ECM without fixing the root cause will lead to repeat failure.
Corrosion inside a connector can create enough resistance to trigger P1665 without any visible damage to the wire insulation.
Some Kia models group injectors and ignition coils differently, so always verify which actuators belong to power stage group 'A' using the factory service information.
Intermittent P1665 codes that appear only under high engine load often point to a marginal injector or coil that tests good at idle.

Can I keep driving with P1665?

You can drive cautiously to a repair shop if the engine runs smoothly and the check engine light is steady, but avoid heavy acceleration or towing. If the engine misfires severely, loses power, or the check engine light flashes, stop driving and have the vehicle towed to prevent catalytic converter damage.

Tools that help

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Guidance is general and written for Kia vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.