Need help to identify emission problem (2016 XC90 T6)
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Hello,
I will really appreciate it if anyone can give me some hints on what's going on with my car here. (2016 XC90 T6)
I use VDASH to do the car readout. It shows the emission system is not Okay with errors in EVAPorative systems. But I cannot see any error code associated with emission problems.
Before this problem came up, I had just changed the fuel pressure sensor, as the car previously was giving out a pressure sensor failure code "P018D00" as well as a fuel system error under readiness emission codes. After the sensor replacement, this code disappeared.One thing a bit strange I noticed is that before I changed this sensor, the car's fuel pressure would gradually drop overnight (or maybe the fuel inside the fuel line is somehow drained after parking for a long time: 8-12 hours). The car engine will have to crank multiple cycles to start (~8-12 cycles, depending on how long I parked). This is sort of confirmed by disconnecting the fuel hose in the morning -- No pressure in the fuel line, and nothing is dripping out. However, after changing the sensor, this has not happened again.
Come back to this evaporative system error. This error was not there before I changed the fuel pressure sensor. It came up right after I changed the sensor and test-drove the car. Here is the screenshot of the VDASH.
Since there is no error code, I decided to read some live ECU data logging. I selected EVAP Temperature CCM, EVAP Monitor, and EVAP Purge valve to display. The temperature is around 0-5 C. and the valve is pretty responsive to my gas paddle. Just the EVAP Monitor data stream is giving me a strange Zig-Zag curve. I want to know what this EVAP Monitor is monitoring, and is this ZigZag a normal behavior?
Any help is greatly appreciated!
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Readiness codes are only relevant for emission tests and don't mean there's anything wrong with car when one or more tests show not ok. When the car has been parked and is cold, lots of those tests will show not okay. Drive around for 20-30 minutes and check again.
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The zig zag lines are a normal PWM signal. Not sure if the values are correct as I don't have access to an official VIDA subscription to check. But looks normal.
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@T5-T6-Schnappi
I actually have driven the car for maybe around 15 min before doing the readout. I did turned off the engine and turned it back on when I was trying to connect to the VDASH. My emission is due in about 2 weeks, and I am just a bit nervous, haha.
