P122C Buick 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 Buick 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 Buick 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 Buick?
- 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 Buick?
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 Buick 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 Buick Code
1. What does the OBDII code P122C mean on a Buick?
P122C indicates a problem with the Intake Air Flow Valve Control Circuit, specifically that it is shorted or malfunctioning.
2. What are the common symptoms of the P122C code in a Buick?
Symptoms may include reduced engine performance, poor acceleration, rough idling, or the check engine light being illuminated.
3. What causes the P122C code to appear?
Common causes include damaged wiring in the intake air flow valve circuit, a faulty intake air flow valve, or a malfunctioning powertrain control module (PCM).
4. Can I drive my Buick with the P122C code?
While the car may still be drivable, it is not recommended as the issue can lead to reduced performance and potential further damage to engine components.
5. How do I fix the P122C code on my Buick?
Repairs may involve inspecting and repairing wiring or connectors, replacing the intake air flow valve, or reprogramming or replacing the PCM if necessary.
6. How is the P122C code diagnosed?
A technician will use a scan tool to verify the code, inspect the intake air flow valve and its wiring, and perform tests to identify the exact component causing the issue.
7. What tools are needed to repair the P122C code?
You may need a diagnostic scan tool, a multimeter to check wiring, and possibly replacement parts like the intake air flow valve or related connectors.
8. How much does it cost to fix the P122C code in a Buick?
The repair cost can range from $100 to $600 depending on whether the issue is with wiring, the valve, or the PCM.
9. Can a dirty air filter cause the P122C code?
No, a dirty air filter is unlikely to cause this code—it specifically relates to the electrical circuit of the intake air flow valve.
10. Will clearing the P122C code fix the issue?
Clearing the code may temporarily turn off the check engine light, but the underlying problem must be resolved to prevent the code from returning.
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