TPS Voltageweirdness
Thread Starter
Burning Brakes
Joined: Jul 2014
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TPS Voltageweirdness
I am in the process of hooking up my NX Express Window Switch. I used the white wire from the ECU in the passenger fender/footwell. When I did my setup with the engine not running and pedal to the floor I am only seeing 2.5v from TPS white wire. Idle shows 0.5v. Is this normal? Shouldn't it be 5.0v?
Tech Contributor
Joined: Dec 1999
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
There are TWO variable resistors in the TPS. Each is reversely proportional to the other
Each resistor has three wires. 5 VDC Ref, TP Sensor signal and a LOW Ref.
One resistor 5 VDC Ref is DK Green, TP Sensor Sig is DK Blue and the Low Ref is PPL
The other resistor is 5 VDC Ref yel/black stripe, TP Sensor Sig is Pink and the Low Ref is White
Your are on the LOW ref (Circuit ground)
Bill
Each resistor has three wires. 5 VDC Ref, TP Sensor signal and a LOW Ref.
One resistor 5 VDC Ref is DK Green, TP Sensor Sig is DK Blue and the Low Ref is PPL
The other resistor is 5 VDC Ref yel/black stripe, TP Sensor Sig is Pink and the Low Ref is White
Your are on the LOW ref (Circuit ground)
Bill
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 801
Likes: 31
There are TWO variable resistors in the TPS. Each is reversely proportional to the other
Each resistor has three wires. 5 VDC Ref, TP Sensor signal and a LOW Ref.
One resistor 5 VDC Ref is DK Green, TP Sensor Sig is DK Blue and the Low Ref is PPL
The other resistor is 5 VDC Ref yel/black stripe, TP Sensor Sig is Pink and the Low Ref is White
Your are on the LOW ref (Circuit ground)
Bill
Each resistor has three wires. 5 VDC Ref, TP Sensor signal and a LOW Ref.
One resistor 5 VDC Ref is DK Green, TP Sensor Sig is DK Blue and the Low Ref is PPL
The other resistor is 5 VDC Ref yel/black stripe, TP Sensor Sig is Pink and the Low Ref is White
Your are on the LOW ref (Circuit ground)
Bill
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 801
Likes: 31
I have not done anything like this. I am working to hook up a NX Express window switch.
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 801
Likes: 31
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Moderator, Tech Contributor
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From: Cape Coral, Florida
First you said "FOOTWELL"...yes, the PCM is inside the passenger side "FENDERWELL" !!...I trust you Bro...with this window switch you are trying to install why are you testing the TPS Sensor ???????
Last edited by C5 Diag; Oct 18, 2018 at 04:09 PM.
Thread Starter
Burning Brakes
Joined: Jul 2014
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So I tapped into the White wire that goes to the PCM in the fenderwell. It it definitely tied to the TPS as it goes up and down voltage as I move the pedal. It maxes out at 2.5v which I was expecting 5.0v. Is getting only 2.5v max out of the white wire normal?
Tech Contributor
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The white wire is a ground ref. Dont know what the needs of the window switch is but I would suspect it is looking for the actual TS signal circuit voltage
Moderator, Tech Contributor
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From: Cape Coral, Florida
Why are you checking TPS signal voltage at the PCM ????...you do it at the TPS sensor which is on the right hand side of the throttle body...it has 6 wires...the dark blue and the pink wires are your signal wires...the white wire is a "low reference" (ground) and it goes from the TPS to the TAC Module...whatever you are doing are you tapped into the TAC Module pin #10??...that's not the PCM my friend...I think you will have problems hooking up this NX Express window switch there...sorry but I can't help you any further...if I were you I have this thing professionally installed. I don't want to see you frying your TAC Module or PCM !!...good luck !!!
Thread Starter
Burning Brakes
Joined: Jul 2014
Posts: 801
Likes: 31
Why are you checking TPS signal voltage at the PCM ????...you do it at the TPS sensor which is on the right hand side of the throttle body...it has 6 wires...the dark blue and the pink wires are your signal wires...the white wire is a "low reference" (ground) and it goes from the TPS to the TAC Module...whatever you are doing are you tapped into the TAC Module pin #10??...that's not the PCM my friend...I think you will have problems hooking up this NX Express window switch there...sorry but I can't help you any further...if I were you I have this thing professionally installed. I don't want to see you frying your TAC Module or PCM !!...good luck !!!
I made a mistake in my writing in the previous posts.