AutoCodes – GMC – P122C GMC

P122C GMC Code - Intake Air Flow Valve Control Circuit Shorted

Quick Answer

The intake airflow valve of diesel engines reduces the intake air flow rate in part-load operation so that a higher exhaust gas recirculation rate can be achieved. Common causes include Faulty Throttle Body Assembly, Throttle Body Assembly harness is open or shorted, Throttle Body Assembly 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: P122C GMC indicates Intake Air Flow Valve Control Circuit Shorted.
Common causes: Common causes include Faulty Throttle Body Assembly, Throttle Body Assembly harness is open or shorted, Throttle Body Assembly 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.

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Code Popularity 468

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Jun 09, 2022

Description
Possible Causes
How To Fix
Tech Notes ▶
Cost to Diagnose
FAQs
Comments
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Code P122C GMC Description

The intake airflow valve of diesel engines reduces the intake air flow rate in part-load operation so that a higher exhaust gas recirculation rate can be achieved.
The Intake airflow valve assembly contains a contactless inductive throttle position sensing element that is managed by a customized integrated circuit. The valve position sensor is mounted within the valve body assembly and is not serviceable. The Engine Control Module (ECM) supplies the valve body with a 5 V reference circuit, a low reference circuit, an H-bridge motor directional control circuit, and an asynchronous signal/serial data circuit. The asynchronous signal means communication is only going from the intake airflow valve to the ECM. The Intake Air Flow Valve cannot receive data from the ECM over the signal/serial data circuit. The valve position sensor provides a signal voltage that changes relative to the valve blade angle. The valve position sensor information is transmitted between the Intake Air Flow Valve and the ECM on the signal/serial data circuit.
The valve may also be used to shut down the engine by closing the intake airflow valve and disabling the fuel injectors if the control module detects the engine speed is beyond the desired control limits. The Diagnostic Trouble Code (DTC) will be set if the ECM detects a high current short circuit on the intake airflow valve control circuit for greater than 0.5 s.

OBDII Code P122C GMC - Intake Air Flow Valve Control Circuit Shorted - AutoCodes.com — P122C GMC Code - Intake Air Flow Valve Control Circuit Shorted

What does this mean?

What are the Possible Causes of the DTC P122C GMC?

Faulty Throttle Body Assembly
Throttle Body Assembly harness is open or shorted
Throttle Body Assembly circuit poor electrical connection
Faulty Engine Control Module (ECM)

How to Fix the DTC P122C 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

User Submitted Video

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P122C 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.

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Information for Specific GMC Models

P122C 2014 GMC Sierra — Intake Air Flow Valve Control Circuit Shorted
P122C 2015 GMC Sierra — Intake Air Flow Valve Control Circuit Shorted
P122C 2016 GMC Sierra — Intake Air Flow Valve Control Circuit Shorted
P122C 2017 GMC Sierra — Intake Air Flow Valve Control Circuit Shorted
P122C 2018 GMC Sierra — Intake Air Flow Valve Control Circuit Shorted

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 P122C GMC Code

1. What are the common symptoms of OBDII code P122C (GMC) related to the Intake Air Flow Valve Control Circuit Shorted?

- Common symptoms include rough idling, engine stalling, decreased fuel efficiency, and a noticeable decrease in engine performance.

2. What are the possible causes of the Intake Air Flow Valve Control Circuit Shorted code P122C in a GMC vehicle?

- Possible causes may include a faulty intake air flow valve, damaged wiring or connectors in the circuit, or a malfunctioning engine control module (ECM).

3. How can I diagnose the issue causing OBDII code P122C (GMC) related to the Intake Air Flow Valve Control Circuit Shorted?

- Diagnose the issue by inspecting the intake air flow valve and its wiring, checking for any visible damage or corrosion. Use a multimeter to test the circuit's continuity and resistance.

4. Is it safe to continue driving with the P122C code indicating the Intake Air Flow Valve Control Circuit Shorted in my GMC vehicle?

- It is not recommended to continue driving with this code present, as it can lead to further engine damage or safety issues. Prompt attention and repair are advised.

5. How can I repair the Intake Air Flow Valve Control Circuit Shorted issue causing OBDII code P122C in my GMC vehicle?

- Repair may involve replacing the faulty intake air flow valve, repairing or replacing damaged wiring or connectors, or reprogramming the engine control module (ECM).

6. Can a DIY enthusiast fix the OBDII code P122C (GMC) related to the Intake Air Flow Valve Control Circuit Shorted?

- While some basic troubleshooting like checking connections can be done by a DIYer, diagnosing and repairing the root cause may require professional expertise and specialized tools.

7. Will resetting the OBDII system clear the P122C code indicating Intake Air Flow Valve Control Circuit Shorted in my GMC?

- Resetting the system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear after driving cycles.

8. How much can I expect to pay for repairing the Intake Air Flow Valve Control Circuit Shorted issue causing OBDII code P122C in a GMC vehicle?

- Repair costs can vary depending on the specific cause of the issue, but expect to pay anywhere from $100 to $500 for parts and labor.

9. Are there any preventive measures to avoid encountering the P122C code related to the Intake Air Flow Valve Control Circuit Shorted in my GMC vehicle?

- Regular maintenance, such as cleaning the intake system and inspecting wiring for wear, can help prevent issues leading to this OBDII code.

10. Can a dealership or an independent mechanic better address the OBDII code P122C (GMC) related to the Intake Air Flow Valve Control Circuit Shorted?

- Both dealerships and independent mechanics can effectively diagnose and repair this code; choose the option that offers the best service quality and pricing for your situation.