AutoCodes – Generic – P0C66

P0C66 Code - Generator Position Sensor Circuit 'A' Low

Quick Answer

A resolver is a sensor that is used to detect the position of the magnetic poles the rotor of a motor generator. Common causes include Faulty Inverter with converter assembly, Faulty Hybrid vehicle generator assembly, Faulty Hybrid vehicle motor assembly. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0C66 indicates Generator Position Sensor Circuit 'A' Low.
Common causes: Common causes include Faulty Inverter with converter assembly, Faulty Hybrid vehicle generator assembly, Faulty Hybrid vehicle motor assembly.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,833

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Feb 13, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0C66 Description

A resolver is a sensor that is used to detect the position of the magnetic poles the rotor of a motor generator. Knowing the position of the poles is indispensable for ensuring precise control of MG2 and MG1.
Each resolver contains a stator that has an excitation coil and 2 detection coils (S, C). The gap between the stator and rotor changes as the rotor turns because the rotor is oval shaped. An alternating current with a predetermined frequency flows through the excitation coil, and detection coils S and C output alternating currents in accordance with the sensor rotor position.
The inverter with converter assembly (MG ECU) detects the absolute position of the rotor according to the phases of detection coils S and C and the heights of their waveforms. Furthermore, the CPU calculates the amount of change in the position within a predetermined length of time, in order to use the resolver as a speed sensor.
The MG ECU monitors signals output from the motor resolver and detects malfunctions.

OBDII Code P0C66 - Generator Position Sensor Circuit 'A' Low - AutoCodes.com — P0C66 Code - Generator Position Sensor Circuit 'A' Low

What does this mean?

What are the Possible Causes of the DTC P0C66?

Faulty Inverter with converter assembly
Faulty Hybrid vehicle generator assembly
Faulty Hybrid vehicle motor assembly
Wire harness or connector

How to Fix the DTC P0C66?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0C66 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0C66 Code

1. What does the OBDII code P0C66 mean?

P0C66 indicates a problem with the Generator Position Sensor Circuit 'A,' specifically a low voltage signal detected by the vehicle's engine control module (ECM).

2. What are the common symptoms of code P0C66?

Symptoms may include the check engine light turning on, reduced charging from the alternator, difficulty starting the vehicle, or battery drain.

3. What causes the P0C66 code to appear?

Possible causes include a faulty generator position sensor, damaged wiring or connectors in the sensor circuit, or issues with the alternator.

4. Can I drive my car with the P0C66 code?

It is possible to drive short distances, but prolonged driving may result in battery failure or reduced system performance, so it should be addressed promptly.

5. How do you diagnose the P0C66 code?

Technicians typically inspect the sensor, alternator, and associated wiring for damage, use a multimeter to test circuit voltage, and may perform a scan to check for related codes.

6. What repairs are needed to fix P0C66?

Repairs may involve replacing the generator position sensor, repairing or replacing damaged wiring, or replacing the alternator if it is faulty.

7. How much does it cost to repair the P0C66 code?

Repair costs vary but typically range from $200 to $500 depending on the part that needs replacement and labor costs.

8. Can a weak battery cause the P0C66 code?

A weak battery is unlikely to cause this code directly, but it can exacerbate issues with the alternator or sensor performance.

9. How can I prevent the P0C66 code from recurring?

Regular maintenance of your charging system, including checking wiring, connectors, and the alternator, can help prevent this issue.

10. Does P0C66 affect fuel efficiency?

While it primarily impacts the charging system, a malfunctioning alternator or sensor could indirectly affect fuel efficiency due to increased engine load.