A weak or failing battery or charging system causing overall low voltage; Corroded, loose, or damaged wiring or connectors on the injector group B supply circuit; A faulty fuel injector with an internal short or high resistance affecting the sense circuit; A blown fuse or faulty relay that supplies power to the injector group; A defective powertrain control module voltage sensing circuit or internal fault; High resistance in a ground connection shared by the injectors or the control module; Aftermarket accessories or improper wiring repairs that add excessive load to the circuit

DTC codes / P2Cxx · Hybrid propulsion / P2C27

P2C27Fuel Injector Group B Supply Sense Circuit Low

Q: What does code P2C27 mean?

Fuel Injector Group B Supply Sense Circuit Low. P2C27 indicates that the powertrain control module has detected a low voltage condition on the supply sense circuit for fuel injector group B, which is a set of injectors that share a common power feed. The circuit is monitored to ensure the injectors receive adequate voltage for proper opening and closing; a low reading means the computer sees less voltage than expected on that supply line.

P2C27 indicates that the powertrain control module has detected a low voltage condition on the supply sense circuit for fuel injector group B, which is a set of injectors that share a common power feed. The circuit is monitored to ensure the injectors receive adequate voltage for proper opening and closing; a low reading means the computer sees less voltage than expected on that supply line.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaHybrid propulsion

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or misfire under load if the low voltage affects injector operation
Reduced engine power or hesitation during acceleration
Poor fuel economy due to incomplete combustion
In rare cases, the engine may stall or be hard to start
A faint fuel odor may be present if injectors are not firing correctly

Common causes, most likely first

A weak or failing battery or charging system causing overall low voltage
Corroded, loose, or damaged wiring or connectors on the injector group B supply circuit
A faulty fuel injector with an internal short or high resistance affecting the sense circuit
A blown fuse or faulty relay that supplies power to the injector group
A defective powertrain control module voltage sensing circuit or internal fault
High resistance in a ground connection shared by the injectors or the control module
Aftermarket accessories or improper wiring repairs that add excessive load to the circuit

How to diagnose and fix it

Perform a battery and charging system test to rule out low system voltage as the root cause
Inspect the injector group B supply circuit wiring and connectors for corrosion, chafing, or looseness
Check the fuse and relay that provide power to the injector group and replace if faulty
Measure voltage at the injector supply sense circuit with a multimeter and compare to specifications
Test each fuel injector in group B for resistance and compare to the manufacturer's specification
Perform a voltage drop test on the ground circuit to ensure a solid connection
If all external circuits and components test good, diagnose the powertrain control module for an internal sensing fault

What the supply sense circuit really monitors

The supply sense circuit is a low-current monitoring line, so a fault code can set even when the injectors still fire normally; many vehicles exhibit no driveability symptoms.
A weak battery or failing alternator is a common root cause that is often overlooked because the code points to the injector circuit, not the charging system.
Corrosion inside a connector can increase resistance without visibly damaging the wire, so a thorough wiggle test and voltage drop measurement are essential.
The code does not necessarily mean the injectors themselves are bad; the supply circuit, fuse, relay, and grounds must be verified first.
On some vehicles, the injector group B supply is shared with other components, so a fault in a seemingly unrelated circuit can set this code.

Can I keep driving with P2C27?

If the check engine light is on but the engine runs smoothly, you can drive cautiously to a repair shop, but avoid heavy loads and long trips. If you notice misfiring, rough running, or stalling, stop driving and have the vehicle towed to prevent catalytic converter damage or unsafe driving conditions.

Tools that help

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