P122B 2015 GMC Sierra Code - Intake Air Flow Valve Control Supply Voltage Circuit
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
- P122B 2015 GMC Sierra indicates Intake Air Flow Valve Control Supply Voltage Circuit.
- 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 P122B 2015 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 an open circuit on the intake airflow valve control circuit.
What are the Possible Causes of the DTC P122B 2015 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 P122B 2015 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 P122B 2015 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 P122B 2015 GMC Sierra Code
1. What does the OBDII code P122B mean on a 2015 GMC Sierra?
P122B indicates an issue with the Intake Air Flow Valve Control Supply Voltage Circuit, which means the engine control module (ECM) has detected a problem with the electrical supply to the intake air flow valve.
2. What are the common symptoms of the P122B code?
Symptoms may include reduced engine performance, poor acceleration, engine hesitation, the check engine light turning on, and possible limp mode activation.
3. What causes the P122B code to appear on a 2015 GMC Sierra?
Common causes include a faulty intake air flow valve, damaged wiring or connectors in the circuit, a blown fuse, or a malfunctioning engine control module (ECM).
4. Can I drive my 2015 GMC Sierra with the P122B code?
Driving with this code may result in reduced performance and could harm the engine over time. It’s best to address the issue as soon as possible.
5. How do I diagnose the P122B code?
Start by inspecting the intake air flow valve wiring and connectors for damage or corrosion. Check the fuse for the circuit, and use a multimeter to test voltage and continuity in the circuit.
6. How do I fix the P122B code on a 2015 GMC Sierra?
Repairs may include replacing a faulty intake air flow valve, repairing or replacing damaged wiring or connectors, or replacing a blown fuse. In rare cases, the ECM may need reprogramming or replacement.
7. How much does it cost to fix the P122B code?
Repair costs can vary depending on the issue. Replacing an intake air flow valve typically costs $150–$400, while wiring repairs or ECM replacements can be more expensive.
8. Can a dirty air filter cause the P122B code?
A dirty air filter alone is unlikely to trigger this specific code, but it can contribute to airflow issues. Ensure the air filter is clean as part of your diagnostic process.
9. Will clearing the P122B code with a scanner fix the problem?
Clearing the code may turn off the check engine light temporarily, but it won’t fix the underlying issue. The code will likely return if the root cause isn’t resolved.
10. Is the P122B code related to other intake system issues?
Yes, it may be associated with other intake system faults, such as a malfunctioning throttle body or mass airflow sensor. It’s important to perform a thorough diagnosis to rule out related problems.
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