AutoCodes – GMC – P2078 GMC

P2078 GMC Code - Intake Manifold Tuning Valve Position Sensor Circuit High Voltage

Quick Answer

An Intake Manifold Tuning (IMT) Valve is used to change the intake manifold plenum configuration. Common causes include Faulty Intake Manifold Tuning Valve, Intake Manifold Tuning Valve harness is open or shorted, Intake Manifold Tuning Valve 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: P2078 GMC indicates Intake Manifold Tuning Valve Position Sensor Circuit High Voltage.
Common causes: Common causes include Faulty Intake Manifold Tuning Valve, Intake Manifold Tuning Valve harness is open or shorted, Intake Manifold Tuning Valve 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 2,333

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 Nov 13, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
Add Comment

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

Code P2078 GMC Description

An Intake Manifold Tuning (IMT) Valve is used to change the intake manifold plenum configuration. When the IMT valve is open, the intake manifold is configured to one large plenum. When the IMT valve is closed, the intake manifold is configured to 2 smaller plenums. The IMT valve improves engine performance at low and high engine speeds depending on the engine load. The Diagnostic Trouble Code (DTC) will set when the control module detects that the state of the driver and the state of the circuit do not match. The control module will detect an open, short to ground on the variable tuning valve signal or an open or a short to ground on the ignition voltage circuit of the IMT valve solenoid for more than 6.25 seconds.

OBDII Code P2078 GMC - Intake Manifold Tuning Valve Position Sensor Circuit High Voltage - AutoCodes.com — P2078 GMC Code - Intake Manifold Tuning Valve Position Sensor Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P2078 GMC?

Faulty Intake Manifold Tuning Valve
Intake Manifold Tuning Valve harness is open or shorted
Intake Manifold Tuning Valve circuit poor electrical connection

How to Fix the DTC P2078 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 P2078 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 P2078 GMC code?

Need more information on how to fix the P2078 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P2078 GMC code diagnosed by a professional: Find a repair shop in your area

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 P2078 GMC Code

1. What are common symptoms of OBDII code P2078 GMC?

- Common symptoms include a Check Engine Light (CEL) illuminated on the dashboard, reduced engine performance, rough idling, and decreased fuel efficiency.

2. What does the OBDII code P2078 GMC indicate?

- The code indicates a high voltage condition in the circuit of the Intake Manifold Tuning Valve Position Sensor.

3. What are the possible causes of OBDII code P2078 GMC?

- Possible causes include a faulty intake manifold tuning valve position sensor, damaged wiring or connectors in the sensor circuit, or a problem in the engine control module (ECM).

4. How can I diagnose the cause of OBDII code P2078 GMC?

- Diagnosis involves using a scan tool to retrieve the code and then inspecting the intake manifold tuning valve position sensor, wiring, and connectors for any visible damage or issues.

5. Can I continue driving with OBDII code P2078 GMC?

- It is not recommended to drive with this code present, as it can lead to further engine damage and reduced performance.

6. What is the repair process for OBDII code P2078 GMC?

- The repair process typically involves replacing the faulty intake manifold tuning valve position sensor, repairing any damaged wiring or connectors, and clearing the code from the ECM.

7. How much does it cost to repair OBDII code P2078 GMC?

- Repair costs can vary depending on the extent of the issue, but replacing the sensor and addressing any wiring problems can range from $200 to $500 at a professional repair shop.

8. Can I fix OBDII code P2078 GMC myself?

- If you have the necessary tools and knowledge, you may be able to replace the sensor or repair wiring yourself. However, it is recommended to consult a professional if you are unsure.

9. Are there any preventative maintenance tips to avoid OBDII code P2078 GMC?

- Regularly inspecting and maintaining the intake manifold tuning valve position sensor and its related components can help prevent this code from appearing.

10. How urgent is it to address OBDII code P2078 GMC?

- It is recommended to address this code as soon as possible to prevent further damage to the engine and ensure optimal performance of the vehicle.