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.