P122C 2018 GMC Sierra 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 2018 GMC Sierra 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.
Code P122C 2018 GMC Sierra Description
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.
What are the Possible Causes of the DTC P122C 2018 GMC Sierra?
- 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 2018 GMC Sierra?
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 P122C 2018 GMC Sierra 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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Frequently Asked Questions about P122C 2018 GMC Sierra Code
What does the OBDII code P122C mean on a 2018 GMC Sierra?
P122C indicates a problem with the Intake Air Flow Valve Control Circuit, specifically a short in the circuit.
What are the symptoms of P122C on a 2018 GMC Sierra?
Common symptoms include reduced engine performance, poor throttle response, potential limp mode activation, and the check engine light turning on.
What causes the P122C code to appear?
Possible causes include damaged wiring, a shorted intake air flow valve, a faulty control module, or corroded electrical connectors.
Can I drive my 2018 GMC Sierra with a P122C code?
While the truck may still drive, it can experience reduced performance and may not operate efficiently, so addressing the issue promptly is recommended.
How do I diagnose the P122C code on my GMC Sierra?
Start by using an OBDII scanner to confirm the code, then inspect the intake air flow valve wiring and connectors for damage or corrosion.
What tools do I need to troubleshoot the P122C code?
You’ll need an OBDII scanner, a multimeter to check for shorts or voltage issues, and basic hand tools to inspect wiring and connectors.
How is the P122C code typically fixed?
Repairs may involve replacing damaged wiring, cleaning or replacing corroded connectors, or replacing the faulty intake air flow valve.
Could a failing intake air flow valve cause other issues?
Yes, a malfunctioning valve can negatively affect airflow, leading to performance issues, increased emissions, or poor fuel economy.
What is the cost to fix the P122C code on a 2018 GMC Sierra?
Repair costs vary but typically range from $100 to $500, depending on whether wiring, connectors, or the intake air flow valve itself needs replacement.
Does the P122C code require reprogramming the ECM?
In most cases, reprogramming is not required, but it may be necessary if the ECM has been damaged or replaced.
Discuss the causes and fixes for P122C 2018 GMC Sierra OBDII Code
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