A faulty position sensor (resolver or encoder) on drive motor B, particularly the 'A' signal winding or circuit; Damaged, chafed, or corroded wiring in the sensor circuit, often near connectors or where the harness bends; A loose or contaminated electrical connector at the motor position sensor or at the control module; Internal failure in the motor control module or inverter that processes the sensor signal; Mechanical issues such as a damaged tone ring or resolver rotor that disrupts the signal; Electrical interference from a failing component or poor grounding that corrupts the sensor signal; Moisture intrusion into the sensor or connector, leading to intermittent or out-of-range readings

DTC codes / P0Cxx · Hybrid propulsion / P0C56

P0C56Drive Motor B Position Sensor Circuit A Range/Performance

Q: What does code P0C56 mean?

Drive Motor B Position Sensor Circuit A Range/Performance. P0C56 indicates that the hybrid or electric vehicle's control module has detected an out-of-range or performance fault in the position sensor circuit for drive motor B, specifically the 'A' signal channel. The computer compares the expected sensor voltage or signal pattern against what it actually receives and flags this code when the signal falls outside the valid range or does not change as expected during motor operation.

P0C56 indicates that the hybrid or electric vehicle's control module has detected an out-of-range or performance fault in the position sensor circuit for drive motor B, specifically the 'A' signal channel. The computer compares the expected sensor voltage or signal pattern against what it actually receives and flags this code when the signal falls outside the valid range or does not change as expected during motor operation.

SystemPowertrain

Code typeGeneric (all makes)

SeverityHigh

Fix difficultyProfessional

AreaHybrid propulsion

Symptoms you may notice

Illumination of the check engine light or hybrid system warning lamp, often with no other noticeable symptoms
Reduced power or a limp-home mode that limits vehicle speed and acceleration
The vehicle may refuse to start or shift into gear if the fault is severe
Rough or inconsistent motor operation, such as shuddering or hesitation during acceleration
A message on the dash indicating a hybrid system fault or that the vehicle needs service
In some cases, the engine may run but the electric drive may be disabled entirely

Common causes, most likely first

A faulty position sensor (resolver or encoder) on drive motor B, particularly the 'A' signal winding or circuit
Damaged, chafed, or corroded wiring in the sensor circuit, often near connectors or where the harness bends
A loose or contaminated electrical connector at the motor position sensor or at the control module
Internal failure in the motor control module or inverter that processes the sensor signal
Mechanical issues such as a damaged tone ring or resolver rotor that disrupts the signal
Electrical interference from a failing component or poor grounding that corrupts the sensor signal
Moisture intrusion into the sensor or connector, leading to intermittent or out-of-range readings

How to diagnose and fix it

Inspect the motor position sensor connector and wiring for signs of damage, corrosion, or loose pins, and clean or repair as needed
Check the sensor circuit for continuity and resistance against the manufacturer's specifications using a multimeter
Perform a visual inspection of the sensor and tone ring for mechanical damage or debris, if accessible without major disassembly
Use a scan tool to monitor live position sensor data and compare it with expected values during a test drive or static test
Test the sensor with an oscilloscope to verify the signal waveform is clean and within amplitude and frequency limits
If the sensor is faulty, replace it following the manufacturer's procedure, which may require special tools or calibration
After repair, clear the codes and perform a relearn or calibration procedure if required, then verify the fault does not return

What the resolver signal reveals

A common mistake is replacing the motor position sensor when the real problem is a damaged wiring harness near the motor mount or a corroded connector that only acts up under vibration.
This code can be set by a weak or failing 12-volt auxiliary battery on some hybrids, because low voltage can disrupt the sensor reference signal and cause false range errors.
The 'A' circuit often refers to one of multiple signal windings in a resolver; a fault in the 'B' or 'C' circuit may set a different code, so always check for related codes before condemning the sensor.
Intermittent faults that appear only when the motor is hot or after a long drive often point to a failing sensor winding that opens up with temperature, not a wiring issue.
A performance code rather than a circuit low/high code suggests the signal is present but implausible, which can be caused by a slipped or damaged resolver rotor rather than an electrical open.

Can I keep driving with P0C56?

Do not continue driving with this code if the vehicle is in limp mode or the hybrid system is disabled, as you may lose power unexpectedly. If the car still drives normally, limit driving to a short distance to a repair shop and avoid heavy acceleration or high speeds.

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.