VW Sharan Oil Pressure Warning, Sensor Issues Explained

Had almost the exact same issue on my 2004 VW Touran diesel last year. As someone with moderate experience working on VWs, I initially thought it was the oil pressure sensor itself. The temp sensor and oil gauge warnings started appearing out of nowhere, particularly after cold starts. After scanning, it showed similar error codes related to the oil pressure system. Took it to a workshop where they found the actual problem was a damaged wiring connection to the oil pressure automotive sensor. The cable insulation had worn through, causing intermittent signals. The repair involved replacing the wiring harness section and connections to the engine sensor, costing 95€ total. Before spending money though, what specific error codes are you getting? Also, have you noticed any patterns when the warnings appear, cold start, during acceleration, or at idle? This information would help determine if your issue matches what I experienced. A proper diagnosis should include: Full sensor signal testing, Checking the wiring connections at the oil pressure sensor, Verifying actual oil pressure with mechanical gauge, Testing the temp sensor readings What engine variant does your Sharan have? These systems can vary between engine codes, so that detail would help provide more specific guidance.

Thanks for the detailed response. Last service was done at 96190km and they didnt spot any issues back then. After the warning lights started appearing, I checked the codes again using my basic scanner. Getting P0523 and P0524 consistently now. The warnings seem most frequent during cold starts and sometimes flash briefly during normal driving. Interesting point about the wiring, I noticed some oil residue near the car sensor area which could have affected the connections. Will check the harness for any visible damage before going further. The timing matches what you described, warnings started appearing more frequently after particularly cold mornings. My engine variant is the 1.9 TDI, if that helps with the diagnosis steps you mentioned. Would you recommend starting with testing the oil temperature sensor connections before moving to the pressure testing?

Thanks for those additional details. Yes, those same error codes appeared on my Touran before discovering the wiring issue. Based on your description, it sounds nearly identical to what I experienced, especially with the cold start symptoms. The oil residue you mentioned near the car sensor is a critical clue. On these 1.9 TDI engines, even small oil seepage can degrade the wiring insulation over time. The engine temperature fluctuations make this worse, particularly during cold starts when the oil is thicker. Given your symptoms, I would recommend this diagnostic sequence: 1. Clean the oil residue completely from the sensor area 2. Inspect the wiring harness leading to both the oil pressure and oil temperature sensors 3. Test the sensor connections with a multimeter 4. Only proceed with car diagnostics for pressure testing if these checks show no issues The repair cost should be similar to what I paid (95€) if its just the wiring. However, if the oil sensor itself is damaged, expect to pay more. In my case, the sensor was fine once the wiring was fixed. Keep monitoring those specific error codes. If they clear after fixing any wiring issues, you will know you found the root cause, just like in my case with the Touran.

Thanks for all the input on this. I've decided to tackle the wiring inspection first based on the similarities with your Touran case. Just checked the area around both the oil pressure and temperature sensor more thoroughly after cleaning off the residue. Found some pretty worn wiring insulation near where the temp sensor connects, looks like oil has been slowly degrading it just as you described. The error codes are still consistent (P0523 and P0524) but knowing these matched your situation with the wiring gives me more confidence about the repair path. Planning to test the car sensor connections with a multimeter tomorrow once I can borrow the proper testing equipment. Will start with replacing that section of the wiring harness since it seems the most likely culprit, especially given how the symptoms match your experience, cold start warnings and intermittent signals. If that doesnt resolve it, will move on to the full pressure testing you suggested. Really helpful to know the repair cost was reasonable in your case. Will update once I get the wiring sorted to confirm if it fixes the engine temperature warnings like it did on your vehicle.