Engine-Codes - Generic - P122C

P122C Code - Intake Air Flow Valve Control Circuit Shorted

- Code Popularity: 2,726 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the DTC P122C?

NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
  • Faulty Throttle Body Assembly
  • Throttle Body Assembly harness is open or shorted
  • Throttle Body Assembly circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

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How to Fix the DTC P122C?

Check the 'Possible Causes' listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector pins.

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What is the Cost to Diagnose the Code?

Labor: 1.0

The cost to diagnose the P122C code is 1.0 hour of labor. The diagnosis time and labor rates at auto repair shops vary depending on the location, make and model of the vehicle, and even the engine type. Most auto repair shops charge between $75 and $150 per hour.

What are Code Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

What Does the P122C Code Mean?

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.

P122C Code - Intake Air Flow Valve Control Circuit Shorted

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