The check engine light suddenly came on in the Civic a few months ago. The engine was running fine, but the light stayed on. I used my little Autel OBDII scanner to scan the codes: P1336, P1337.
P1337 Honda – Crankshaft Position Sensor 2 No Signal
P1336 Honda – Crankshaft Speed Fluctuation Sensor Intermittant Interruption
Both codes have the same possible causes:
- Faulty Crankshaft Position Sensor
- Crankshaft Position Sensor harness is open or shorted
- Crankshaft Position Sensor circuit poor electrical connection
Both codes have the same possible symptoms:
- Engine Light ON (or Service Engine Soon Warning Light)
- Lack/Loss of Power
- Engine Stall
The engine has not been stalling or lacking power. I have seen no difference in performance at all. As I read more, I found that this sensor detects problems, but it doesn’t affect how the engine runs. I was confident that the problem was with the sensor, not the engine, so I ignored it up until now. It failed safety inspection so my quest for a solution began.
This video was the first thing that came up, and happened to be very useful.
It is in Spanish, but the visuals should be helpful. The guy starts out talking about the code, and showing the possible cause on the screen of his code scanner. The note he pays attention to is this:
“Techs in field report that wire harness rubbing against alternator belt may be the cause of DTC. Fix wire harness & insert back in track on upper timing belt cover.”
He then goes on to show how the smaller of the wiring harnesses is too close to the alternator belt. Between 4:08 and 4:11, if you know what to look for, you can see the belt is cutting into the segmented harness shield. It is difficult to see, and he keeps trying to give a better view. Around 5:08 the car is running and it’s easier to see the ragged edge where the belt is cutting into the harness like a saw. The harness is jiggling and if you follow it to the left where it touches the belt, you will see the problem.
He then shows the same problem from underneath the car. If you had a hard time seeing what was going on before, this should make it clearer. The cable shield has been chewed into, and the wires are clearly damaged.
The root cause of the harness coming in contact with the belt is that the harness has come out of the track that secures it, or someone took it out for service and forgot to put it back in. The track is a long slot along the edge of the timing belt cover, and the harness snaps into it.
The video was helpful to show the problem, and I went out to check my car. Sure enough, I saw the exact same thing.
View from above. The arrow points to the place where the belt and harness are making contact.
View from underneath the car. The belt has cut into the wiring harness
View from underneath the car. Closeup of the damage to the wiring harness
Understanding the problem, and fixing it, are two different things, as I was about to find out.
The tricky part: getting the connector unplugged
I spent about 3 hours trying to get the plug for the wiring harness disconnected. There were several factors:
- I didn’t fully understand how the connector worked
- The space is very tight. It’s difficult to get a pair of hands in there.
Getting the connector free was a crucial part of the process that I could not find fully explained anywhere. I found a page with some good photos and info, but not enough information to tell me why the front part of the connector wouldn’t budge, even though I had managed to get the two halves to start coming apart. I suspected that something was holding it in place, but I couldn’t see what it was.
BIG clue and time saver:
The bottom of that connector is secured to a strong metal tab by a plastic clip. No amount of ‘fidgeting’ is going to get it off unless you break it. To get the connector off the metal tab there is a little plastic push tab underneath the connector that must be pushed up. At the same time you must pull out on the connector assembly to get it to slide off the metal tab. It isn’t easy, but once you know what the goal is, it becomes possible. Once the connector is off the metal tab, there is another push tab on the top that must be pressed down in order to get the connector assembly apart.
“A” is a metal tab that connector “C” slides onto. “B” is the other half of the connector
It really helped me to find an example of a connector that worked in a similar way. Luckily, there is a gray plug to the right of the dipstick that you can experiment on. I practiced taking it off the metal tab and putting it back on in order to get an idea of how to do it in the cramped space.
The connector near the dipstick may help you understand that needs to be done to get the other one apart. They aren’t necessarily identical, but they are very similar.
I found that I was able to get more room for my hands by temporarily removing a couple of brackets. One is held in place with a 10mm bolt and the other with a 10mm nut. The brackets can be slid out of the way, but remember to put them back!
Once I got the connector apart, the rest of the procedure was much easier, although it still took some doing.
Here are the steps I took to solve the problem:
- Disconnect the wiring harness connector (see commentary above).
- Remove the driver’s side wheel. You are going to be working inside that wheel well, so make sure you are parked on a level surface, that your emergency brake is engaged, and that you have a jack stand or something strong and secure to keep the car from falling on you if it gets bumped.
- Remove 3 plastic connectors that hold the plastic wheel well shroud in place. I didn’t remove the shroud entirely. I just undid enough connections to get it out of my way. Two of the connectors were plastic screws that were easy to remove. The other was a snap-in connector that didn’t survive. Auto parts stores carry them if you need to replace the ones that break.
- Pull the wiring harness down past the belts until it hangs in the wheel well. You can’t see the gray connector hiding behind the brake. You can see the plastic hanging down, and above the pulleys you can see two of the holes where it was attached. The third hole is off to the left, out of sight.
With the wheel well shroud out of the way, the wiring harness can be pulled down into the wheel well for a better look.
- Snip the harness at the point of the damage. I just clipped right through the middle.
Wiring harness closeup clearly shows the damage from the alternator belt
- Slide off the protective tubing from both pieces of harness. It would be in the way otherwise. But, remember it will need to go back on.
In order to work on the wires, slide the tubing off temporarily
- For each of the “cut” ends of the harness, carefully cut a slit several inches long on the outside insulation and pull it back to show more of the inside wires. I used a box cutter to do it, but I only cut deep enough to score the gray insulation and pull it back. Preserve as much of the metal shield as possible.
Make a slit in the gray insulation and peel it and the metal shield back to work on the wires
- Cut each of the wires to the same length, trying to preserve as much of the length as possible. Bare the ends of the wires about 3/8″.
Bare and twist the wires in preparation for soldering
- For the two pieces of black protective tubing, make a 2-inch slit at the “cut” end of each piece.
- Temporarily join the all the wires and insulation, then slide the black protective tubing back onto the harness wires. Use the slit in the tubing to peel it back so you can start joining the wires.
Temporarily join all the wires together to slide the black tubing back on.
With the black tubing to the side you can prep the wires for soldering.
- Twist the blue wires together and solder the twisted part. I could just as easily have started with white, but blue got twisted first and I went with it. I ran a long, heavy extension cord out to the car. My soldering iron is about 30 years old, so I’m not sure the wattage is. It’s something similar to this one. The solder I used is fairly thin. If you haven’t soldered before, it’s very important to use solder that is made for electronics and not for plumbing (rosin core solder is what you want). If you haven’t soldered before, you might want to try crimp connectors instead. I didn’t use them because I worried they might be too thick.
Twist blue wires together and solder the joint.
- Bend the soldered “tab” over to lie parallel to the blue wire. This is the make the repair as thin as possible.
Bend the solder joint over to lie parallel with the blue wire.
- Use strips of electrical tape to tightly wrap the repaired blue wire. I cut pieces of electrical tape and then sliced them in half length-wise. The thin pieces are easier to manage, which ends up in a thinner repair. You want all the repaired wires to fit nicely back into the black tubing when you’re finished.
Wrap the blue wire with tape and then twist and solder the white wire.
- Now twist the white wire ends together, and solder. Bend the soldered part over and use thin strips of electrical tape to wrap the white and blue wires together. The blue wire was already wrapped so I just wrapped the white and blue together.
Bend the solder joint parallel with the white wire and tape it to the already-taped blue wire. Then twist and solder the ground (uninsulated) wires.
- Twist the ground wires together and solder.
- Use strips of aluminum foil to wrap around the 3 wires. This is to replace the metal shielding. It doesn’t matter that the foil is touching the bare wire.
Aluminum foil from the kitchen to replace the metal shielding.
Wrap the foil strips around the repaired wires. It won’t matter that it’s touching the bare ground wire. This looks a little messy, but it gets pressed it tighter to the wires later on.
- Put the outside plastic insulation around the foil. Cut the insulation shorter if it’s too long.
Put gray insulation back over the repair and the foil. Originally it overlapped, so I cut the gray insulation to touch but not overlap.
- Wrap neatly with electrical tape.
Wrap the repair with electrical tape. I tried to make the repair as thin as possible to fit back into the black tubing.
- Slide the black protective tubing together over the joint.
I slid the pieces of harness tubing together so I could wrap them with electrical tape.
- Finish up with a wrap of electrical tape.
This is the final repair. I tried to make it as thin as possible to fit into the harness groove.
- Pull the harness back up into position and plug it together. (I didn’t put it back on the metal clip until I was able to test it.)
- Push the wiring harness into the groove around the edge of the timing belt cover. Hopefully your repair isn’t too thick. It should snap into the slot, away from the alternator belt. I used a 1/2″ wooden dowel as a lever to push it in.
- Replace the plastic wheel well shroud.
- Replace the wheel.
- Once everything is back together, clear the codes and see if the check engine light stays off. So far mine has stayed off. After 5 days of not CEL I’m going to call this one a success.
When I saw how much of a pain this procedure was, I decided to document the procedure for anyone who might be in my same situation. I hope you find it helpful.
UPDATE 09/14: After almost a month the check engine light is still off, and I was able to pass inspection.
UPDATE 06/15: Still going with no issues.