P0120 and P0301 Codes

[whitedragon551]

Well got the SUV running after changing out cap, rotor, and plugs. Now Im getting a P0301 Number 1 cylinder misfire and a P0120 Throttle position sensor code. I assume neither are related.

Where do I go from here?

[whitedragon551]

Bump. Need some guidance here.

[Towncivilian]

Make sure you didn't accidentally loosen any hose or intake tubing.

For P0120, try following the diagnostic procedure on EC-150.

Did you use the OEM specified spark plugs?

Sorry for the delay in responding.

[whitedragon551]

Make sure you didn't accidentally loosen any hose or intake tubing.

For P0120, try following the diagnostic procedure on EC-150.

Did you use the OEM specified spark plugs?

Sorry for the delay in responding.

OEM specified plugs. They werent NGK's though. They were the AC Delco equivalent.

I will test for P0120 tonight and go over every harness and tube we touched.

Is it likely the P0120 is causing the misfire?

[Towncivilian]

I'm not sure if they're related. But the FSM says to diagnose P0120 before any of the cylinder misfire codes, so get that one fixed first.

[whitedragon551]

Alright so of I check the harness and everything checks out there its a bad sensor
My question is there are 2 harnesses there. We did unplug them. Its possible my dad swapped them and plugged them into the wrong socket and I don't think they are color coded. How do I determine which harness goes where definitively?

[Towncivilian]

Compare the colors of the individual wires (if you can see them) to the ones listed in the FSM.

[whitedragon551]

Compare the colors of the individual wires (if you can see them) to the ones listed in the FSM.

Wiring colors arent listed in the Diagnostics for P0120. They are listed as pin numbers.

[Towncivilian]

See the wiring diagram on page EC-149. Colors are listed.

[whitedragon551]

See the wiring diagram on page EC-149. Colors are listed.

Doh. I was going off of the page number in Adobe, not the actual page number on the pages. They are off by about 6 pages.

[whitedragon551]

Plugs were on the right spots. All hoses and harnesses were connected.

I wasnt able to get an accurate reading from the harness.

However, I wonder if I installed the throttle position sensor correctly after I removed it.

There is the gold bar that the TPS goes over. That gold bar goes to the valve opening and closing for throttle. On the TPS there is a spring like mechanism. Does that spring go in front/right of the gold bar or does it go behind the gold bar? To get it in front you kind of have to put it in crooked and turn it so the screw holes line up. Doing it this way my idle RPM was roughly 13-1500. Before that it was at about 5-700.

The spring in the TPS only moves one way. It appears if you just drop it in and bolt it in place the valve position doesnt move that sensor spring.

Here is a quick paint drawing I did to try and display what I was talking about.

[Towncivilian]

I'm afraid I have no idea as to the orientation of the TPS. I guess you can try swapping it to the other way and see if the code goes away, if I follow you correctly.

[whitedragon551]

I'm afraid I have no idea as to the orientation of the TPS. I guess you can try swapping it to the other way and see if the code goes away, if I follow you correctly.

I think the second way I did it is wrong. An idle of 1500RPMS's seems to be excessive.

[Towncivilian]

Yes, 1500RPM warm idle is too high. It should be 750 +/- 50.

[whitedragon551]

Yes, 1500RPM warm idle is too high. It should be 750 +/- 50.

Considering the vehicle ran fine when it was shut off and nothing is burnt/melted. Is it safe to assume the TPS needs replaced? I cant get a good reading with my DMM on the harness pins.