PicoScope 7 Automotive
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R53 Cam sensor anomaly
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alexanderfitu
- Newbie
- Posts: 2
- Joined: Tue Jul 12, 2022 7:07 pm
R53 Cam sensor anomaly
Hi all
I have a 2003 Mini cooper R53 here, that logs an intermittent P0340 and P0341 code (Cam sensor signal missing or circuit fault). Its had a new sensor already same fault. I suspect the ECU is at fault here, so I scoped the output of the sensor. The Cam sensor points at a wheel with 2 evenly spaced raised sections, so the signal should be regular hi/lo for every rotation of the cam.
This is the signal I scoped at the ECU connector whilst the fault was active:
As the fault was intermittent, I grabbed one whilst the fault was not active:
As this is the 3rd sensor this car has had (1 sensor fitted by previous garage, and one sensor I have in stock swapped in). I suspect there is an internal ECU fault pulling up the signal line to 5V.
I scoped the signal lines on the hall sensor, with the signal pin and ground removed from the ECU And grounded separately, as I was missing the pull up/down resistor inside the ECU , the signal was much lower, but as you can see it becomes normal again:
I would love somebodies second opinion as to whether I am on the right track.
Many thanks
I have a 2003 Mini cooper R53 here, that logs an intermittent P0340 and P0341 code (Cam sensor signal missing or circuit fault). Its had a new sensor already same fault. I suspect the ECU is at fault here, so I scoped the output of the sensor. The Cam sensor points at a wheel with 2 evenly spaced raised sections, so the signal should be regular hi/lo for every rotation of the cam.
This is the signal I scoped at the ECU connector whilst the fault was active:
I scoped the signal lines on the hall sensor, with the signal pin and ground removed from the ECU And grounded separately, as I was missing the pull up/down resistor inside the ECU , the signal was much lower, but as you can see it becomes normal again:
Many thanks
Re: R53 Cam sensor anomaly
Ecu job is to provide 5V. Its the job of the sensor to pull that to ground.
You’re looking to:
- aftermarket bad sensors
- magnetized trigger wheel
- distance sensor trigger wheel incorrect.
You’re looking to:
- aftermarket bad sensors
- magnetized trigger wheel
- distance sensor trigger wheel incorrect.
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alexanderfitu
- Newbie
- Posts: 2
- Joined: Tue Jul 12, 2022 7:07 pm
Re: R53 Cam sensor anomaly
So this is a 12v sensor.
It receives 12V from a relay that is energised by the engine ecu. This voltage has been scoped and is present and not intermittent. The same result is found when supplying the sensor with a 12v signal directly from the battery.
So you are implying that the signal will be 5V the entire time, until the sensor detects metal, then shunts to ground.
This is a new BMW OEM sensor, and this behavior is present on 3 different sensors, so I would be surprised if this is a sensor fault (but I have had worse luck)
It receives 12V from a relay that is energised by the engine ecu. This voltage has been scoped and is present and not intermittent. The same result is found when supplying the sensor with a 12v signal directly from the battery.
So you are implying that the signal will be 5V the entire time, until the sensor detects metal, then shunts to ground.
This is a new BMW OEM sensor, and this behavior is present on 3 different sensors, so I would be surprised if this is a sensor fault (but I have had worse luck)
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wiki38andy
- OneWave
- Posts: 28
- Joined: Sat Apr 18, 2020 4:45 pm
Re: R53 Cam sensor anomaly
See if the CMP signal failure happens on the same trigger wheel teeth or is randomly.