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Replacing the speed sensors

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jimnvicki, Jun 30, 2010.

  1. jimnvicki

    jimnvicki New Member

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    2006 Prius
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    I bought two new factory fresh speed sensors to replace the ones I shredded by not following you guy's advise about removing them before i replaced the front hub/bearing assemblies. Lesson learned. So, after work tonight I get the car up on jack stands and replace both sensors in about 45 minutes. Easy right? Get it off the jack stands, torque down the rims and reset the dash lights. Sweet! Nice clean dash display with no warning lights. I drive it down the street, nice speedometer display and then, after about 100 yards, the warning lights come on and the speedometer flickers from 22mph to 2 then 10 then 1 then zero. I drive it back home, check the sensors and the connections, reset the lights again, drive it down the street and, same story. What have I done wrong? I am in a serious quandry. My wife is ready to torch the car tonight, but we have to get to work in the morning. Any ideas? Thanks
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    What warning lights have come on? I think you'll need to try to figure out what codes exist so that you can get a hint about what the problem is.

    If the warning lights relate to ABS, BRAKE (the circle with exclamation point within) or VSC, then it is possible to retrieve blink codes by shorting two pins in the DLC3 connector. Make the car IG-OFF, jump pins 4 and 13 together, then make the car READY and see which warning light blinks a two-digit code. Note the warning light and its blink code and post your findings.
     
  3. jimnvicki

    jimnvicki New Member

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    Hey Pat! I hope you had a great day. All the lights blink in a repetitive pattern. VSC: 4 blinks then 3. ABS: 3 blinks then 1, 3 blinks then 2, 3 then 5, 3 then 6. Brake: 3 blinks then 6. Tire inflation pressure: 3 blinks then 4. Jeez, does all this make sense to you? I dont mean to monopolize your time on here and I really appreciate your expertise. Thanks again.
     
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Jim:

    ABS blink codes 31, 32: right front and left front speed sensor circuits, skid control ECU

    ABS blink codes 35 and 36: foreign matter on the tip of the RF and LF speed sensors, chipped teeth on the rotor within the hub bearing assembly that induces electrical pulses in the sensor, bad wiring harness, skid control ECU

    VSC blink code 43: brake control power supply issue: what is the condition of your 12V battery? If marginal replace that now.

    Brake blink code 36: Yaw rate sensor zero point calibration needed. This requires the Toyota diagnostic laptop.

    I understand you've installed new parts. Any dirt on the sensors or chipping of the rotor teeth? Make sure that the sensor wiring harness connectors are secure.

    Once you've checked your work and do not find any issues, I suppose you'll need to depend upon Toyota dealer service to determine the root cause of the problem. Good luck.
     
  5. jimnvicki

    jimnvicki New Member

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    Thank you, Patrick, for providing me with this data. The car is going to the dealer this morning. When I installed the new speed sensors, everything looked clean. I didnt particularly notice any chipped teeth. Thanks again, for the taking the time to look this up and write it in here. We might be buying a replacement for the Prius this weekend.
     
  6. jimnvicki

    jimnvicki New Member

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    What if there was dirt in the connector before the speed sensor? the one at the top of the wheelwell? Would that generate any of these codes?
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, if you have bad wiring harness connections then that would cause several of the codes that your car logged.