P21B0 Zagato Bravo Diagnostic Trouble Code

P21B0 Zagato Bravo code definition:
P21B0 is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Zagato Bravo.

P21B0 Zagato Bravo is described as Oxygen Sensor Circuit No Activity Detected (Bank 1, Sensor 1). This means there's a problem in the front oxygen sensor on Bank 1, as the O2 sensor is inactive. If the car doesn't start, they will proceed by testing the voltage at the fuel pump connector and see if the fuel pump relay, fuse, and PCM circuitry should be inspected.

Symptoms

Symptoms of a P21B0 Zagato Bravo diagnostic trouble code may include:

Vacuum leak on the engine
Reduction in engine performance, especially at low RPM levels
Engine surge
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

Fuel with a large percentage of sulfur will clog the DPF quickly
The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)

Common Misdiagnoses

Crankshaft Position Sensor Circuit Performance Problem
TP Sensor Learn Not Complete Problem
Low Coolant Circuit Problem
Cruise Control System - Vehicle Accel Too High Problem
Kick-Down Switch Failed Short Problem

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. Replace the oxygen sensor that is downstream from the catalytic converter on the side of the engine that does not contain cylinder #1. Also, if a oxygen sensor code stating "heater circuit malfunction" the sensor has most probably failed. If all testing has passed so far yet you still have the same code, check your scan tool and see if it can open and close the IMRC valve.

Process Tips

Diagnostic trouble code P21B0 Zagato Bravo is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before P21B0 Zagato Bravo.

Fortunately, P21B0 Zagato Bravo is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.