P1212 - FAULT CODE - OBD2

P1212 BUICK, CADILLAC, CHEVROLET, GMC: MASS AIR FLOW CIRCUIT INTERMITTENT LOW

The electric fuel injection system has the MAF sensor (Mass Air Flow Sensor). This sensor is installed between the intake manifold and the air filter. It measures how much air enters the engine or the airflow. An electronic chip is installed inside the sensor, which translates the current into a voltage signal that is provided to the Powertrain Control Module (PCM). The PCM uses it to calculate how much fuel to inject to maintain the air-fuel ratio at its optimum level.

The Air Mass Flow Sensor has a wire that is electronically heated. This is known as a hot wire. When the engine is idling, a small amount of air flows around the wire, so a very low current is necessary to keep the wire warm. When the throttle is pressed, the throttle opens and allows more air to flow over the wire, requiring more electric current to keep it hot, which is proportional to the amount of airflow.

The P1212 OBDII diagnostic code setting occurs when an irregular operation is detected in the mass airflow circuit, which has experienced voltages that are not within the manufacturer’s allowable voltages.

• Check Engine light ON.
• Problems starting the engine.
• After starting the motor, it stalls.
• Exhaust emissions increase.

Reasons for setting the P1212 OBD2 DTC P1212 OBD2 code:

• There may be intake leaks.
• The Mass Air Flow Sensor wiring or connectors may be damaged.
• The MAF Sensor may have inconsistencies in its circuit voltages due to poor electrical connections.
• The MAF sensor may be faulty.

Steps for troubleshooting the P1212 OBDII fault code:

• Consult the Technical Service Bulletins.
• Use a scanner to check if other DTCs are stored. Pay more attention to those related to intake air leaks. If this is the case, correct these leaks.
• Check the wiring, as well as the respective MAF Sensor connectors for damage caused by burns or corrosion. In any of these conditions, make repairs or replace these components.
• Check the Air Mass Flow Sensor for contamination or other conditions that would cause it to malfunction. Fix if necessary
• Measure the values of the air mass flow sensor circuit and compare them with those indicated in the service manual. As this code indicates, you should observe a value below the specified value. In case there is no damage to its wiring or electrical connections, repair as necessary.
• If you do not discover any damage to the electrical circuit components, there may be a bad MAF sensor. You could replace it.