I have a tp switch not a tps sensor on my 90 740 turbo. I tired at turbobricks but they couldnt help. I just need to know if 1.7ohms means that my tp switch is either good or bad thanks?

 

anything? Tech maybe you know? If it helps I do have a code 133 tps and it also clicks when I move it.

 

the switch part of it is just to tell the ecu that the throttle is closed. It should just click when the throttle closes and is adjustable.Loosen then turn slowly until it just clicks then tighten down. The other 3 wires work as a normal throttle position switch. Not sure about turbos but this is how it is on the non turbo cars. Cant tell you about the ohm reading but with key on and measureing the voltage off of the signal wire you should get .5v at idle and 4.5v at wot

 

I know how to test the voltage for tps. this is my 1st volvo and one with a tp switch. ok tomorrow I will check the voltage of the signal wire. the ohms I got with key off was 1.7 on the full connecter

 

You really should have no more than .5 ohms. I would replace it, especially if there was also a DTC set.

Make sure when your reading resistance to touch the two multimeter leads together and subtract that number from your reading.

Often when the TPS is failing, the resistance will change, keep opening and closing the switch while checking the readings and see if you get different readings. Make sure the switch is disconnected when you check it.

Check the terminals in the connector and make sure they are not corroded and not too spread apart. Use some dielectric grease when you re-install the connector.

Make sure you tighten the ground wires on the intake manifold. If these are loose they can give you the same code.

B

 

it was odd today when checking the ohms, the load part of the switch had contunity which most likey means the switch is bad, the middle and full load contact came up with ohms. yet the car has been driving fine.