DIY: Crank Angle Sensor (Code 4) Replacement...No Pics

[sam o nela]

Originally posted by Maytagman

got a code 4?
your crank angle sensor is bad...
and the worst part is its behind the front cam gear!
so many people im sure have replaced their timing belt in order to replace their crank sensor... if you are paying a mechanic its probably a $900-1000 job. but this is not necessary at all!
an experienced mechanic could do this job in an hour without removing the timing belt. it took me about 3 but im slow and take my time... lots of coffee breaks a fair price would be $150-ish for the sensor and $50-150 labour. $300 is a fair price, $200 is a steal.

the crank angle sensor is two magnetic pickups which give a signal when a lobe on the cam gear passes by them. this sensor is redundant as the tdc sensor in the distributer does basically the same thing. however the crank angle sensor adjusts timing so if you have a bad one expect your car to run like crap and suck gas like crazy.

honda SHOULD have just properly engineered ONE GOOD SENSOR. it looks like they over-engineered a simple problem.

how to fix it:

1. jack the car and remove the passenger side wheel. open the timing belt inspection holes on the plastic timing belt covers. the inspection holes are a circle with a notch. go into the wheel well, stick your tire iron on the crank bolt and turn clockwise until you hit TDC or top dead centre. you will know you are at tdc because inside the inspection hole, on the cam pully's are a red line. each cam gear's red line will line up with the notch in the inspection hole at tdc.
2. remove the plastic sheaths over the alt and power steering belts.
3. remove the front timing belt cover. 4 long and 1 short bolts. this is a bitch because of the dip stick and alternator bracket being in the way... wiggle it and it will come out easy enough. this is a good time to check your timing belt for wear or damage. a broken timing belt means you need to replace your whole motor so make sure the belt looks good.
4. take chalk or whiteout and mark the timing belt where it lines up with the red line on the pully. i used chalk and it kept rubbing off so i had to remark it a few times. white out will work better, but i didnt have any.
5. remove the 3 bolts holding the cam gear on. these bolts are TIGHT. pull the gear off and set it aside. the timing belt will stay in place so you dont need to worry about it. do not stuff it down as it could slip a tooth.
you can now see your crank angle sensor.
it looks like this:
the black stuff on the front is a vibration dampening goop/resin. under extreme conditions it can melt. if it melts the internal sensors vibrate and operate under extreme heat and fail very rapidly. there were drips of this goop on my timing belt and inside timing belt cover. a failed sensor will look like it was painted then someone stuck their fingers into the wet paint and messed it all up might post a picture of mine later.
6. remove the inner timing belt cover. i think it is 4 bolts. this was hard to remove to say the least. wiggle and play with it and it will come out eventually.
7. remove the bolt holding the crank angle sensor wire in place and remove the two bolts holding the crank angle sensor. disconnect the sensors two in one connector: one side connects to a bracket attached to the dipstick, the top connects to the wiring harness. i found it quicker to brake the plastic where it attaches to the dip stick than disconnect it. i was also very annoyed at this point.
8. stick your new sensor in place and bolt it in. put the wire holder on the rubber bracket and bolt that in too. new sensor is installed. plug it in.
9. put the inner cover back on and bolt it in place. be VERY carefull not to drop bolts into the lower timing belt cover. i did this but luckily i have a telescopic magnet to quickly pull it out. a must. route the crank angle sensor wire into the cover's wire holder.
10. put the belt on the cam gear and re-lineup the whiteout line you made with the cams red line. put the cam gear back on. this requires a lot of strength. i wasnt strong enough so i had to call my dad over and get him to do it. im only 5'6" and 120 lbs there isnt a good spot to pry it on with a screwdriver so small guys and girls be prepared here bolt the cam gear up and torque it to spec. i dont have a torque wrench so i just did it as tight as itll go
11. ok so you are basically done now... before putting the cover back on go back down to the crank and turn the engine over 6 times and make sure nothing hits. ie. valves on pistons if everything is ok put the timing cover back on and put the belt covers back on and fire it up!
12. NO MORE CODE 4!!!!
woooo hooo!!!!
you just saved yourself at least a days work... or several hundred dollars.
maytag

[1990-5-SPD]

I currently have a faulty Crank Position Sensor 37840-PL2-026. When I find a replacement, your explanation should come in handy.