P039D Buick Roadmaster Diagnostic Trouble Code

P039D Buick Roadmaster code definition:
P039D is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Buick Roadmaster.

P039D Buick Roadmaster 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 P039D Buick Roadmaster diagnostic trouble code may include:

Vacuum leak on the engine
Reduction in engine performance, especially at low RPM levels
Engine surge
Rich or lean exhaust

Possible Causes :

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

Common Misdiagnoses

Vehicle Speed Output Circuit Problem
Cruise Control Servo Indicates Low Problem
A/C System High Pressure High Temperature Problem
PCM Stack Overrun Problem
Transmission Control Module Reprogrammable Memory Problem

Repair Processes :

Look for damage to the tank indicating impact that may have damaged the fuel pump or sender. It should be pretty close to battery voltage (12 volts). If not, then this is the circuit that has the problem.

Process Tips

Diagnostic trouble code P039D Buick Roadmaster 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 P039D Buick Roadmaster.

Fortunately, P039D Buick Roadmaster is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.