2007 S4RS engine and air temp sensor errors

[axle167]

Hi everyone - It has been a while since my last post... which kind of shows how little I've been riding.

The bike now has 60k kms and does not like heat and traffic, which is probably why I don't ride too much.

Anyway, the tech scanned the bike and it shows short to positive or open loop for engine temp and air temp/pressure sensors.  The tech suggests two new engine temp sensors, but I wanted to investigate a bit more myself.  The engine temp to dash works fine.

Here's what I've done with some research.

I unplugged the engine temp to ECU harness and plugged it into the sensor to dash and the temperature shows the same, so I think the sensors are fine.

I tested the harness, the one to ECU shows 5.01v and 4.89v on the black/violet wire(which I think should be 0v) while the harness to dash shows 5.01v and 0v.  I plugged back in the two sensors to their corresponding harness.

I unplugged the air temp/pressure sensors and tested the black/violet wire and that shows 5v (again I think it should be 0).

When both sensors are unplugged, the black/violet line shows 0v, but with any one sensor plugged in, it goes back to readings before.

I then proceed to test for continuity in the black/violet wire from sensors harness to the diagnostic plug and the ECU it shows 0.7.

I'm a bit lost as to where the issue is, but I think this may have contributed to the bike running hotter and crappy.

[Howie]

I'm not sure if you have a real problem.  Is the bike actually overheating?  Are the fans coming on?  At what tempreature

[axle167]

The fans won't come on when the tech tried to turn it on with the scan tool. However, the relay housing is cracked and a new one is on the way.

The bike runs noticeably hotter than before in the same ambient temp. Also, the bike starts to stall and backfire when it reaches about 80c in traffic and gets worse as temp gets higher.

One last note, the headlight housing had a crack and water got inside a while back. The headlight ground was burnt. I replaced the headlight socket, but low beam was very dim with high beam working as normal and high beam indicator always on. The tech said light bulb was burnt and replaced it with and LED bulb and the lights work fine, but I have some doubt the bulb is the issue.

[Howie]

Yep, you clearly have a problem.  I would not ride it until I found a fix.

I can't fond my manual and don't remember the diagnostic procedure for the sensor, but my next step would be to check the relay and make sure the fans work.  Remove the connector at the fan relay and jump from terminal 30 to terminal 85.  Key on, the fans should work.  If the fans work, for now you could hook up a manual switch.

You are probably correct on the bulb.  The LED draws very little current compared to the bulb so the wiring can be rather shabby.

[axle167]

Yes, I now have more problems than I had before!

Check engine light flashed on for few seconds while the bike throttle was not responsive.  Didn't stall, but just not responsive or idles really high like the choke was on.

Took to Tech for the scan and it shows both ignition coils failed (open or short to ground). He cleared the codes and start bike again to see fault comes right back.

He then pulled coils and confirmed fault with multimeter.  I don't know what the multimeter readings are for them i.e. primary vs secondary etc.  Should I ask? Is that important?

He now recommends new coils and NGK CR9EIX sparkplugs.  He also commented on the champion rg4hc plugs that I had in there.

I do feel it is odd that both coils failed at the same time.  What would be my options here?  Are there any other diagnostics we should try?  The bike have 60K kms or 36K miles, are coils expected to fail after awhile?  Are there after market options?

Feedbacks are much appreciated.

[Howie]

I can't find the S4 manual, so no info on specs.  Just make sure you don't have to pay for the coils unless the problem is fixed.  If the relay is no good the scan tool will not run the fans.  I do agree with your tech about the plugs.  Oh, and I agree it unlikely both coils to go bad at the same time.  If they did, there probably is a cause that needs to be repaired.

Again, if the relay is bad, remove the connector at the fan relay and jump from terminal 30 to terminal 85.  Key on, the fans should work.  If the fans work, for now you could hook up a manual switch. Or, a new relay is cheap, and good to have as a spare The scan tool will not turn on the fan if the relay is bad.