B3637 BMW Fault Code

Description:

EGR Flow Insufficient Detected The EGR system is monitored during steady state driving conditions while the EGR is commanded on.
The test fails when the signal from the DPF EGR sensor indicates that EGR flow is less than the desired minimum. Vacuum supply EGR valve stuck closed EGR valve leaks vacuum EGR flow path restricted EGRVR circuit shorted to PWR VREF open to D.P.F. EGR sensor D.P.F. EGR sensor downstream hose off or plugged EGRVR circuit open to PCM VPWR open to EGRVR solenoid D.P.F. EGR sensor hoses both off D.P.F. EGR sensor hoses reversed Damaged EGR orifice tube Damaged EGRVR solenoid Damaged PCM Perform KOER self-test and look for DTC B3637 as an indication of a hard fault.

B3637 Code Symptoms :

The original multi-displacement system turned off opposite pairs of cylinders, allowing the engine to have three different configurations and displacements. B3637 code had an elaborate diagnostics procedure, including showing engine trouble codes on the air conditionning display. However, the system was troublesome, misunderstood by customers, and a rash of unpredictable failures led to the technology being quickly retired.

Diagnosis And Repairing B3637

B3637 OBD2 reports a sensor fault, replacement of the sensor is unlikely to resolve the underlying problem. The fault is most likely to be caused by the systems that the sensor is monitoring, but might even be caused by the wiring to the sensor itself.

How to fix B3637 code ?

• Dirty Oil
• Camshaft Position Sensor harness is open or shorted
• Air fuel ratio (A/F) Sensor 1 Bank 1 circuit poor electrical connection
• Oil flow restriction in the oil passages or the variable camshaft timing (VCT) valve body

As long as the throttle plate remains closed, the idling speed and quality is controlled by the PCM via the idle control valve, and as can be seen from the above it should be clear that idle control on a gasoline engine is a complex affair.

For instance, if the engine is started in sub-zero temperatures, the PCM will command the idling control valve to allow less air to enter the engine to enrich the air/fuel mixture to create a condition which is roughly analogous to how chokes worked on carburetted engines to control idling in cold weather.