P0437 Diagnostic Trouble Code

P0437 is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a P0437 diagnostic trouble code may include:

Faulty or damaged wiring
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly
Poor fuel economy
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

A large air leak at or near the number one oxygen sensor would also cause a lean mixture.
Faulty IMRC actuator relay (if equipped)
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. 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.

Process Tips

Diagnostic trouble code P0437 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 P0437.

Fortunately, P0437 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

P0437 Trouble Code For Specific Cars

P0437 Nissan Teana Cylinder #1 High To Low Side Open
P0437 Lancia Fulvia Speed Wheel Sensor Rear Center Input Short Circuit To Battery
P0437 Volvo 260 SCP (J1850) Invalid or Missing Data for Displays
P0437 Saab 99 Ignition Tach Circuit Short To Ground
P0437 Mercedes C 63 ABS Inlet Valve Coil Rear Circuit Failure
P0437 Kieft 1100 Servo Motor Potentiometer Airintake Left Circuit Failure
P0437 Ferrari 801 Intake Valve Control Solenoid Circuit Range/Performance (Bank 2)