# Car check engine light came on today..

**URL:** <https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863>\
**Category:** Shift518 Automotive\
**Created:** [October 26, 2009, 1:37pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863 "2009-10-26T13:37:28Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![Oleg](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/oleg/32/6276_2.png) [@Oleg](https://forums.speedlife.net/u/Oleg)\
**Post date:** [October 26, 2009, 1:37pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/1 "2009-10-26T13:37:28Z")

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Hey guys, I was hoping someone could help me out.  
My 94 accord’s check light came on, I just checked the code by jumping the input connector wires and it seems to be 31 (3 long 1 short).  
From what I found it could be either  
**31** P1686 A/T FI Signal B Low Input  
**31** P1687 A/T FI Signal B High Input

Edit;  
Automatic Transmission Signal “B” defective circuit or unplugged / defective sensor  
Anyone know what circuit/sensor that is?  
Is the tranny toast or something not quite that bad?

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**Author:** ![Ilya](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilya/32/6404_2.png) [@Ilya](https://forums.speedlife.net/u/Ilya)\
**Post date:** [October 26, 2009, 1:45pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/2 "2009-10-26T13:45:20Z")

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Hmmm…what would the tranny have to do with FI?

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**Author:** ![Ilya](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilya/32/6404_2.png) [@Ilya](https://forums.speedlife.net/u/Ilya)\
**Post date:** [October 26, 2009, 1:47pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/3 "2009-10-26T13:47:32Z")

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[http://www.honda-tech.com/showthread.php?p=40343523](http://www.honda-tech.com/showthread.php?p=40343523)

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**Author:** ![Oleg](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/oleg/32/6276_2.png) [@Oleg](https://forums.speedlife.net/u/Oleg)\
**Post date:** [October 26, 2009, 1:52pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/4 "2009-10-26T13:52:44Z")

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> [@Club addicts...whats your all-time favorite....](https://forums.speedlife.net/t/club-addicts-whats-your-all-time-favorite/24876/26):
>
> [05 TL Problem - Honda-Tech - Honda Forum Discussion](http://www.honda-tech.com/showthread.php?p=40343523)

Not sure what I’m supposed to glean from that.

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**Author:** ![Ilya](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/ilya/32/6404_2.png) [@Ilya](https://forums.speedlife.net/u/Ilya)\
**Post date:** [October 26, 2009, 2:09pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/5 "2009-10-26T14:09:39Z")

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TPS Sensor. Worth a shot to diagnose (test it with an ohm meter - something I’m not good at).

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**Author:** ![Oleg](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/oleg/32/6276_2.png) [@Oleg](https://forums.speedlife.net/u/Oleg)\
**Post date:** [October 26, 2009, 3:16pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/6 "2009-10-26T15:16:23Z")

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Hmm, seems I’ve misread the code the first time.  
It’s 4 long and 1 short (I’ll have to triple check to be sure), which it says is a  
ho2s heater sensor.

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**Author:** ![Alpine](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@Alpine](https://forums.speedlife.net/u/Alpine)\
**Post date:** [October 26, 2009, 3:25pm UTC](https://forums.speedlife.net/t/car-check-engine-light-came-on-today/247863/7 "2009-10-26T15:25:51Z")

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Mine came on Saturday while I was driving during that monsoon we got…