AutoCodes – GMC – P2066 GMC

P2066 GMC Code - Fuel Level Sensor 2 Performance

Quick Answer

Diesel Engine The primary fuel level sensor and the secondary fuel level sensor change resistance based on fuel level. Common causes include Faulty Fuel Level Sensor, Fuel Level Sensor harness is open or shorted, Fuel Level Sensor circuit poor electrical connection. 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: P2066 GMC indicates Fuel Level Sensor 2 Performance.
Common causes: Common causes include Faulty Fuel Level Sensor, Fuel Level Sensor harness is open or shorted, Fuel Level Sensor circuit poor electrical connection.
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.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 8,173

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 Jun 29, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P2066 GMC Description

Diesel Engine
The primary fuel level sensor and the secondary fuel level sensor change resistance based on fuel level. The Fuel Pump Driver Control Module monitors the signal circuits of the primary fuel level sensor and the secondary fuel level sensor and sends the signal information to the Engine Control Module (ECM) for all further handling. The ECM uses this value in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level sensors are low, and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sensor and the secondary fuel level sensor. When the fuel tank is empty, the resistances of the fuel level sensors are high, and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sensor and the secondary fuel level sensor in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via the serial data circuit to the instrument cluster in order to control the fuel gauge.

Gasoline Engine
The primary fuel level sensor and the secondary fuel level sensor change resistance based on fuel level. The Engine Control Module (ECM) monitors the signal circuits of the primary fuel level sensor and the secondary fuel level sensor in order to determine the fuel level. When the fuel tank is full, the resistances of both fuel level sensors are low, and the ECM senses a low signal voltage on both the signal circuits of the primary fuel level sensor and the secondary fuel level sensor. When the fuel tank is empty, the resistances of the fuel level sensors are high, and the ECM senses a high signal voltage. The ECM uses the signal circuits of the primary fuel level sensor and the secondary fuel level sensor in order to calculate the percentage of remaining fuel in the tank. The ECM sends the fuel level percentage via the serial data circuit to the instrument cluster in order to control the fuel gauge.

The Diagnostic Trouble Code (DTC) will be set if the ECM detects a change in fuel level of less than a specified amount (typically 3 - 10 L or 0.8 - 2.6 gal) over a specified driving distance (typically 240 - 320 km or 150 - 200 miles).

OBDII Code P2066 GMC - Fuel Level Sensor 2 Performance - AutoCodes.com — P2066 GMC Code - Fuel Level Sensor 2 Performance

What does this mean?

What are the Possible Causes of the DTC P2066 GMC?

Faulty Fuel Level Sensor
Fuel Level Sensor harness is open or shorted
Fuel Level Sensor circuit poor electrical connection
Faulty Instrument Cluster
Faulty Engine Control Module (ECM)

How to Fix the DTC P2066 GMC?

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 does this mean?

Code Tech Notes

A low fuel level can trigger this code. Before replacing any parts, try filling up the fuel tank and erasing the engine code. If the problem persists, it may be necessary to replace the fuel level sensor.

There is a factory service bulletin for the following GMC models:
2007 GMC Sierra 3500 Chassis Cab
2008 GMC Sierra 3500 Chassis Cab
2009 GMC Sierra 3500 Chassis Cab
2007-2009 GMC Sierra 3500 Chassis Cab Factory Service Bulletin ODBII Code P2066

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P2066 GMC 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.

Need more information about the P2066 GMC code?

Need more information on how to fix the P2066 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P2066 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P2066 2014 GMC Sierra — Fuel Level Sensor 2 Performance
P2066 2015 GMC Sierra — Fuel Level Sensor 2 Performance
P2066 2016 GMC Sierra — Fuel Level Sensor 2 Performance
P2066 2017 GMC Sierra — Fuel Level Sensor 2 Performance
P2066 2018 GMC Sierra — Fuel Level Sensor 2 Performance

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.