BMW B48 Case Study: FC 195014 & 191C02

Diagnosing a check engine light on a 2021 BMW X1 with the B48 engine. We investigate fault codes 195014 and 191C02 to determine if the issue is a faulty sensor or the fuel tank vent valve. #bmw #191c02 #195014 0:00 Sneak Peak! Cause of Cel on this BMW X1 fault code 195014 0:22 Checking fault memory with scan tool 0:49 Review freeze frame data 1:15 Location of sensor 1:26 THE Issue! Venturi Pressure sensor 1:37 Multimeter testing of 3 wires (power, ground, signal) 2:00 2.9v from signal with no vacuum applied 2:11 applying vacuum to valve to test if sensor voltage changes 2:25 4.6v from sensor with vacuum applied 2:45 explanation of what sensor voltage should be with no vacuum 3:05 explanation of how venturi sensor can set both faults 3:40 Vehicle repaired with new sensor, reads .8v with no vacuum 3:51 4.6v with vacuum applied 4:05 dtc clear and verify no faults return 4:25 recap of diagnosis and repair See the diagnostic case study here! https://community.topdon.com/detail?i... Vehicle: 2021 BMW X1 F48, with B48 engines. Complaint: CEL is illuminated, but vehicle drives fine. Tools used: Topdon ArtiDiag 800 Bt2, Multimeter, Hand vacuum pump. Diagnosis: Test drove vehicle, verified cel is on but no drivability symptoms present. Pulled Vehicle into workshop, connected power supply, connected 800 Bt2 and carried out full system scan. FC 195014 - Pressure sensor Venturi nozzle in the tank vent line, signal : fixed stored 22 times. Fc 191C02 - Tank ventilation system 2, inlet point : Malfunction stored once. Checked history on vehicle, found vehicle had previously had the fuel tank vent valve already replaced. Most people see fault code 191C02 on a B48 and immediately swap the vent valve—but on this 2021 BMW X1, that would have been a total waste of money. Here’s how I found the real culprit. Removed and inspected tank vent valve, both diaphragms in place. Smoke tested valve, no smoke comes through valve. Carried out bi-directional testing of valve, it can be heard clicking. At this point the fuel tank vent valve passed all applicable testing and fc 191C02 was no longer the main suspect. With the common fix ruled out, I had to dig into the weirdest code on the list: 195014. There is little to no service data on this sensor, and there is no data pid in the DME that can be monitored for the pressure/vacuum reading. However this is a 3 wire vacuum/ pressure sensor and can be diagnosed in a traditional test method. Checked Pin 1 (Blue), 5.030V good 5 v reference. Checked pin 2 (Black&yellow trace), .003v - good ground. Checked pin 3 ( white&yellow trace) 2.715v - This reading was a red flag—it was showing vacuum even though the engine wasn't running. Removed sensor from line, found foreign substance on sensor, and inside of sensor it appeared to have engine oil. Adapted manual vacuum hand pump to valve and applied vacuum, signal voltage of valve now reads 4.683v high voltage equals high vacuum on this valve. Released vacuum and voltage only drops to 2.803v - sensor is suspected to have skewed reading and showing too high of vacuum when none is present. Provided estimate to customer for replacement of venturi line with integrated sensor. Replacement was approved and line with sensor was replaced. Monitored signal voltage of new sensor at rest and found .746v, when vacuum was applied reading achieved 4.681 v. This is more in line with initial suspicion of low vacuum, low voltage, and high vacuum, high voltage. Faults were cleared using the 800 Bt2 and vehicle test driven. Faults did not return and vehicle was released. This is a perfect example of how common problems are not always the correct repair. When carrying out diagnosis all data must be analyzed and a logical testing sequence carried out to ensure proper repairs are carried out the first time. On the b48 driveline you cannot just change the fuel tank vent valve any time that fc 191c02 is stored, if additional faults are stored they must also be considered. Another helpful tip is checking freeze frame data to check the frequency of faults. In this Example 195014 was stored 22 times, to 191c02 being stored only a single time. Also when service data, and available pids are lacking you have to return to fundamentals and carry out testing without there always being a step by step trouble tree. Do you have a check engine light on a BMW with the B48 driveline? If so drop your make and model, and the fault codes and what tests you carried out to diagnose and repair the issue. If you enjoy real-world BMW diagnostics, programming, and repair videos, consider liking and subscribing for more BMW technical content, and to be notified when new case studies are published! #bmw #b48 #bmwrepair #bmwdiy #topdon #artiDiag800bt2 #topdonscanner #automotivediagnostics #mechaniclife #checkenginelight #191c02 #195014 #bmwx1 #f48 #evap #ventvalve #casestudy #diagnostics #bmwservice #mechanictips #coding