VW Polo Stalling: Faulty Camshaft Sensor Alert

Had the exact same problem on a Golf 1.4 from 2004, the symptoms were identical. The engine control unit kept showing misfire codes and the ignition timing was completely off. Being somewhat experienced with engine electronics, I first thought it was just the camshaft sensor, but the workshop found the actual encoder wheel on the camshafts was defective. This caused irregular signals, leading to engine stalling and starting problems. The repair involved replacing both the encoder wheel and sensor. Total cost was 695€ including parts and labor. After the fix, all starting issues disappeared and the engine runs perfectly smooth now. However, to give more specific advice about your case, could you share: Have you checked for any error codes? Does the stalling happen more when the engine is cold or warm? Are there any unusual sounds from the top of the engine? Has there been any recent maintenance work done? The symptoms definitely warrant immediate attention, continuing to drive with incorrect camshaft positioning can cause additional engine damage. Would recommend getting it checked soon, as these issues typically get worse over time.

Thanks for sharing your experience. My Polo was serviced last month, but these issues started recently. I scanned for codes using an OBD reader and got P0340, which points to a camshaft position sensor circuit malfunction. The stalling mostly happens when the engine is cold, especially during the first few minutes after starting. The crankshaft sensor readings also seem erratic during sensor testing. No unusual engine sounds noticed, but the rough idle and stalling are getting more frequent. Based on your repair costs, I will budget around 700€ for the potential fix.

Thanks for the additional details, that P0340 code definitely aligns with what I experienced. The erratic crankshaft sensor readings combined with cold-start issues are classic symptoms of a failing camshaft position sensor system. In my case, testing revealed that the sensor itself was actually fine, but its connection was compromised due to wiring damage. This caused similar engine misfire patterns and cold start problems. The repair ended up being less expensive than replacing the entire sensor assembly, around 250€ for diagnostics and wiring repair. Since you mentioned your car was recently serviced, it might be worth checking if any work was done near the sensor wiring harness. Sometimes unintentional damage can occur during routine maintenance. The car stalling mainly during cold starts suggests sensor failure rather than mechanical issues with the encoder wheel that I had. Given the increasing frequency of stalling, I recommend getting it checked soon. While my Golf remained driveable with these symptoms, the engine misfire eventually got worse and could have caused more expensive damage if left unchecked. Bring those sensor testing results to your mechanic, they will help narrow down whether its a wiring issue like mine or if you need the complete sensor replacement.

Based on your repair experience and the P0340 code, I feel more confident its the camshaft sensor system. The cold start issues match exactly what you described. Ill definitely get it checked this week rather than risk additional engine damage. Good point about checking the recent service work, I just called my regular mechanic and he mentioned they did replace the timing belt last month. The wiring near the camshaft sensor might have been disturbed during that job. The 250€ repair cost for just wiring issues sounds much better than the 700€ I was budgeting for. Ill make sure they thoroughly check the sensor connections and wiring harness first before replacing any parts. Thanks for highlighting how important proper sensor testing and diagnostics are for pinpointing the exact issue. Will update once its fixed in case others run into similar ignition timing problems with their cars. These camshaft sensor failures seem pretty common on these engines.