wadi23 Posted May 4, 2012 Share Posted May 4, 2012 need some help with these codes or more so solutions to these codes. p0720 - output speed sensor circuit malfunction p1718 - AT CAN communication circuit the codes have been cleared but i still have the problems. i'm having erratic shifts and after driving for a couple minutes a flashing "sport" light. the other thing is i cant pass 5000 rpms feels like im hitting a rev limiter. any suggestions would be appreciated. thanks Link to comment Share on other sites More sharing options...
Shades Posted May 4, 2012 Share Posted May 4, 2012 A P0720 Output Speed Sensor Circuit Malfunction trouble code is telling you there’s a problem between how much power is coming into the transmission versus how much power is coming out. The computer knows the RPMs of the engine and which gear you’re in. It also knows your road speed, so it’s able to detect that something is wrong. This could be caused by a slipping clutch, band, or pressure regulator. Or, it could just be a faulty speed sensor. If it is a pressure regulator issue, it may have been caused by boost spike or boost creep. Were you beating on it when this happens? You gotta push your limits to learn your limits:cool: Link to comment Share on other sites More sharing options...
Moderators BarManBean Posted May 4, 2012 Moderators Share Posted May 4, 2012 The TCU can't actually throw codes, so it tells the ECU to throw a CEL. Try clearing the codes and run the car through 4-5 drive cycles. Normal driving, shut the car off, repeat. The problem I see though is that you are reporting erratic shifting, etc--so there could be a real problem. A dealership may be able to reset the TCU so it can relearn as well.... "Bullet-proof" your OEM TMIC! <<Buy your kit here>> Not currently in stock Link to comment Share on other sites More sharing options...
wadi23 Posted May 4, 2012 Author Share Posted May 4, 2012 A P0720 Output Speed Sensor Circuit Malfunction trouble code is telling you there’s a problem between how much power is coming into the transmission versus how much power is coming out. The computer knows the RPMs of the engine and which gear you’re in. It also knows your road speed, so it’s able to detect that something is wrong. This could be caused by a slipping clutch, band, or pressure regulator. Or, it could just be a faulty speed sensor. If it is a pressure regulator issue, it may have been caused by boost spike or boost creep. Were you beating on it when this happens? shades this problem happened when i got back the car from a ishty mechanic that changed my head gaskets. he did that properly but getting those issues now. Link to comment Share on other sites More sharing options...
Shades Posted May 4, 2012 Share Posted May 4, 2012 It sounds like the mechanic may have connected a wire or a harness backwards or possibly missed one. A misconnected wire causing power issues could be causing the erratic shifts. If everything is correct I would agree with BarManBean about taking it to a dealership, even if it's just to have them run a diagnostic on the car which is usually about $100 I believe You gotta push your limits to learn your limits:cool: Link to comment Share on other sites More sharing options...
wadi23 Posted May 8, 2012 Author Share Posted May 8, 2012 if im not mistaken a diagnostic has already been fun that's how i got the codes in my post above. Now i've read that i have a front and rear speed sensor. the front is easy peasy but how do i change the rear as its wired into the harness? Link to comment Share on other sites More sharing options...
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