P1211 - FAULT CODE - OBD2

P1211 BUICK, CADILLAC, CHEVROLET, GMC: MASS AIR FLOW CIRCUIT INTERMITTENT HIGH

The MAF (Mass Air Flow Sensor) is a device installed in the intake manifold that assists the fuel injection system. The MAF sensor measures how much air enters the engine. Then, it sends that data via an electrical signal to the PCM (Powertrain Control Module) to determine the amount of fuel that needs to be injected to achieve a stoichiometric air/fuel mixture.

When the engine is idling, a certain amount of air passes near a wire of the MAF sensor. This wire is electronically heated, so a level of current is required to be sent at idle to maintain this temperature. When the accelerator pedal is depressed, more air flows around the wire, so more current is required to keep the wire at its proper temperature, which happens to be proportional to the airflow.

When the DTC P1211 OBDII code is set, it is due to out-of-range voltages has been found in the MAF Sensor circuit, becoming excessively above the allowed values.

• Check Engine light ON.
• Difficult to start the engine.
• Motor stalling.
• Higher exhaust emissions.

The P1211 OBD2 diagnostic code is set for one of the following reasons:

• The engine may have intake leaks.
• The MAF sensor may have deficiencies in its wiring or connectors.
• The Mass Air Flow Sensor may have a short in its circuit due to bad connections.
• Possibly the MAF sensor is in bad condition.

To solve the P1211 OBDII fault code, try this:

• First, consult the TSBs.
• Check for other DTCs in addition to P1211, pay special attention to those that indicate air leakage conditions. Repair if necessary.
• Check all the electrical circuit components of the Air Mass Flow Sensor. If you find some deficiencies, make the appropriate repairs.
• Check the MAF sensor for contamination conditions. If such deficiencies are detected, make the corresponding adjustments.
• Perform electrical checks on the MAF sensor Take into account that an out-of-range value is due to poor connections. Perform appropriate repairs.
• If no deficiencies are found in the electrical connections or components, the Air Mass Flow Sensor is possibly defective and should be replaced.