P066E GMC Code - Cylinder 3 Glow Plug Control Circuit Low Voltage
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #3 glow plug, Cylinder #3 glow plug harness is open or shorted, Cylinder #3 glow plug 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
- P066E GMC indicates Cylinder 3 Glow Plug Control Circuit Low Voltage.
- Common causes
- Common causes include Faulty cylinder #3 glow plug, Cylinder #3 glow plug harness is open or shorted, Cylinder #3 glow plug 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.
Code P066E GMC Description
Control of the glow plugs is accomplished by the Glow Plug Control Module. The nominal voltage for the glow plugs is 5.4 volts. When the ignition is turned On, the Glow Plug Control Module applies 7.2 V for 2.2 s, then 5.7 V for 0.8 s, and then 5.4 V until 1200°C (2192°F) is reached. The maximum voltage of the system is 10 V. While the engine is running the voltage will vary between 4.7 - 10 V when in closed loop control to maintain a glow plug temperature that ranges from 1150° - 1180°C (2102° - 2156°F). The temperature and the power consumption are controlled between the Engine Control Module (ECM) and the Glow Plug Control Module within a wide range to suit the engine's pre-heating requirements. Each glow plug is energized individually. This capability yields more optimum heat times for the glow plugs, thus pre - glow times can be kept to a minimum for a short wait to crank times and maximum glow plug durability.
What are the Possible Causes of the DTC P066E GMC?
- Faulty cylinder #3 glow plug
- Cylinder #3 glow plug harness is open or shorted
- Cylinder #3 glow plug circuit poor electrical connection
- Faulty Glow Plug Control Module
How to Fix the DTC P066E 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 is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P066E 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 P066E GMC code?
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Need Help with the Code?
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Information for Specific GMC Models
- P066E 2014 GMC Sierra — Cylinder 3 Glow Plug Control Circuit Low Voltage
- P066E 2015 GMC Sierra — Cylinder 3 Glow Plug Control Circuit Low Voltage
- P066E 2016 GMC Sierra — Cylinder 3 Glow Plug Control Circuit Low Voltage
- P066E 2017 GMC Sierra — Cylinder 3 Glow Plug Control Circuit Low Voltage
- P066E 2018 GMC Sierra — Cylinder 3 Glow Plug Control Circuit Low Voltage
Frequently Asked Questions about P066E GMC Code
What does the OBDII code P066E mean for a GMC vehicle?
The P066E code indicates a low voltage issue in the cylinder 3 glow plug control circuit on a GMC vehicle.
What are common symptoms of the P066E code in a GMC?
Symptoms may include difficulty starting the engine in cold weather, poor engine performance, or an illuminated check engine light.
What causes the P066E code on a GMC vehicle?
Common causes include a faulty glow plug, damaged wiring or connectors in the glow plug circuit, a failed glow plug control module, or corroded electrical connections.
Can the P066E code affect engine performance?
Yes, it can cause difficulties in cold starts and may lead to reduced efficiency or uneven combustion in the affected cylinder.
How is the P066E code diagnosed on a GMC?
Technicians use an OBDII scanner, inspect the glow plug and wiring for damage, and test the glow plug control circuit for proper voltage and continuity.
Can I drive my GMC with a P066E code?
While driving may be possible, it is not recommended as cold starts and engine performance may be compromised. Addressing the issue promptly is advised.
How do you fix the P066E code on a GMC vehicle?
Repairs may include replacing the faulty glow plug, repairing or replacing damaged wiring, cleaning corroded connections, or replacing the glow plug control module.
What tools are needed to troubleshoot the P066E code?
You’ll need an OBDII scanner, a multimeter to test voltage and continuity, and basic tools to access and inspect glow plugs and wiring.
Is the P066E code covered under GMC warranty?
This depends on the vehicle’s warranty terms and coverage. Glow plug issues may fall under the powertrain warranty if the vehicle is still within the coverage period.
How much does it cost to fix the P066E code on a GMC?
Repair costs can range from $100 to $400 depending on whether the glow plug, wiring, or control module requires replacement. Labor costs may vary.
Discuss the causes and fixes for P066E GMC OBDII Code
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