PSA: 991 CAN bus speed is 500kbps
04-19-2019, 09:05 PM
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PSA: 991 CAN bus speed is 500kbps
By way of a public service announcement or perhaps a public falling on one's own sword to generate enough embarrassment that I avoid doing the same thing ever again...
The CAN bus speed in the 991 generation cars (at least for CAN MMIO and CAN CHASSIS for certain) is 500kbps.
You do not want to connect CAN bus agents with any other speed. A moment's inattention last night had me hook up a dump tool set for 1Mbps -- there was instant chaos as the dash display blurted out an intimidating array of red and yellow code announcements...the parade went on for quite a while. The most scary [of those that I could decipher] was a red "PSM Failure: park the car". Long story short the car went into a less-than-limp mode as a result. These codes did _not_ clear with cycling the ignition. Gulp. Almost all of the scary ones did clear when I unhooked the battery though; I guess the power on self test cleared a lot of them. Phew!! I was left with a CEL that I couldn't clear though so I had to go find a PIWIS to sort that.
Anyhoo, all recovered now but I think I need to go write out 100 times by morning...pay attention when connecting up to the CAN bus!
The CAN bus speed in the 991 generation cars (at least for CAN MMIO and CAN CHASSIS for certain) is 500kbps.
You do not want to connect CAN bus agents with any other speed. A moment's inattention last night had me hook up a dump tool set for 1Mbps -- there was instant chaos as the dash display blurted out an intimidating array of red and yellow code announcements...the parade went on for quite a while. The most scary [of those that I could decipher] was a red "PSM Failure: park the car". Long story short the car went into a less-than-limp mode as a result. These codes did _not_ clear with cycling the ignition. Gulp. Almost all of the scary ones did clear when I unhooked the battery though; I guess the power on self test cleared a lot of them. Phew!! I was left with a CEL that I couldn't clear though so I had to go find a PIWIS to sort that.
Anyhoo, all recovered now but I think I need to go write out 100 times by morning...pay attention when connecting up to the CAN bus!
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edub (06-10-2022)
04-19-2019, 09:18 PM
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By way of a public service announcement or perhaps a public falling on one's own sword to generate enough embarrassment that I avoid doing the same thing ever again...
The CAN bus speed in the 991 generation cars (at least for CAN MMIO and CAN CHASSIS for certain) is 500kbps.
You do not want to connect CAN bus agents with any other speed. A moment's inattention last night had me hook up a dump tool set for 1Mbps -- there was instant chaos as the dash display blurted out an intimidating array of red and yellow code announcements...the parade went on for quite a while. The most scary [of those that I could decipher] was a red "PSM Failure: park the car". Long story short the car went into a less-than-limp mode as a result. These codes did _not_ clear with cycling the ignition. Gulp. Almost all of the scary ones did clear when I unhooked the battery though; I guess the power on self test cleared a lot of them. Phew!! I was left with a CEL that I couldn't clear though so I had to go find a PIWIS to sort that.
Anyhoo, all recovered now but I think I need to go write out 100 times by morning...pay attention when connecting up to the CAN bus!
The CAN bus speed in the 991 generation cars (at least for CAN MMIO and CAN CHASSIS for certain) is 500kbps.
You do not want to connect CAN bus agents with any other speed. A moment's inattention last night had me hook up a dump tool set for 1Mbps -- there was instant chaos as the dash display blurted out an intimidating array of red and yellow code announcements...the parade went on for quite a while. The most scary [of those that I could decipher] was a red "PSM Failure: park the car". Long story short the car went into a less-than-limp mode as a result. These codes did _not_ clear with cycling the ignition. Gulp. Almost all of the scary ones did clear when I unhooked the battery though; I guess the power on self test cleared a lot of them. Phew!! I was left with a CEL that I couldn't clear though so I had to go find a PIWIS to sort that.
Anyhoo, all recovered now but I think I need to go write out 100 times by morning...pay attention when connecting up to the CAN bus!
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-Peter Krause
www.peterkrause.net
www.gofasternow.com
"Combining the Art and Science of Driving Fast!"
Specializing in Professional, Private Driver Performance Evaluation and Optimization
Consultation Available Remotely and at VIRginia International Raceway