No TPS signal
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No TPS signal
Hey guys I’ve been looking every where and so far no luck so I’m sorry if this is topic wearing thin but anyways-
1989 f150 5.0l
tps has good ground and 5 volt VREF but no signal (it was like .06V the other day but now it’s like barely .01v I’ve tried cleaning the connector and new sensors. probed the MAP sensor and that has 5 volts which I’m pretty sure means it’s not the computer since they’re on the same circuit I think? Out of ideas haha, I appreciate all help thank you
1989 f150 5.0l
tps has good ground and 5 volt VREF but no signal (it was like .06V the other day but now it’s like barely .01v I’ve tried cleaning the connector and new sensors. probed the MAP sensor and that has 5 volts which I’m pretty sure means it’s not the computer since they’re on the same circuit I think? Out of ideas haha, I appreciate all help thank you
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Joined: Dec 2016
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From: Philly
today I found that the wire colors described on the easyautodiagnostics page for Ford straight six and small block tps test are not the same as on my truck. check the wire you found 5 volts on for the signal. just in case. I myself cannot find the 5 volt reference voltage. haven't done any digging on that though. or try to get a better probe connection on the wire that probably should have the signal...
oddly, when probing the wire that should have the signal on my truck, my meter showed .09v and decreased smoothly to .06v when I opened the throttle. I assume that is actually the wire I should have the 5v reference at.
good luck. do try to come back with your findings. nothing worse than an unfinished thread as I'm sure you've already seen.
oddly, when probing the wire that should have the signal on my truck, my meter showed .09v and decreased smoothly to .06v when I opened the throttle. I assume that is actually the wire I should have the 5v reference at.
good luck. do try to come back with your findings. nothing worse than an unfinished thread as I'm sure you've already seen.
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Sorry fod the delay I’ve been out of town and haven’t had time to work on this junk LOL
So I tried the different colored wires but still no luck, the black wire is the correct wire that is a signal but I’m not getting any voltage at all even with the new sensors I’ve tried
So I tried the different colored wires but still no luck, the black wire is the correct wire that is a signal but I’m not getting any voltage at all even with the new sensors I’ve tried
Fleet Owner
Joined: Oct 2005
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From: Kentucky
Some info regarding the TPS signal, return and VREF:
1988-1991 TPS Wire Colors
VREF - Orange/White
TP SIG - Dark Green/Light Green
SIG RTN - Black/White
1992-1996 TPS Wire Colors
VREF - Brown/White
TP SIG - Gray/White
SIG RTN -Gray/Red
Motorcraft TPS Wire Colors
VREF - Orange
TP SIG - Green
SIG RTN - Black
VREF should be ~5 VDC with respect to Signal Return. In reality Signal Return is a dedicated ground so it should be the same reference point as the negative terminal of the battery. The TPS signal should be 0.6 to 1.0 VDC with the Key On Engine Off and the throttle closed. It should increase smoothly to ~ 5 VDC (VREF). Usually it tops out around 4.75 VDC.
If there is no VREF signal, you have bigger issues to deal with.
1988-1991 TPS Wire Colors
VREF - Orange/White
TP SIG - Dark Green/Light Green
SIG RTN - Black/White
1992-1996 TPS Wire Colors
VREF - Brown/White
TP SIG - Gray/White
SIG RTN -Gray/Red
Motorcraft TPS Wire Colors
VREF - Orange
TP SIG - Green
SIG RTN - Black
VREF should be ~5 VDC with respect to Signal Return. In reality Signal Return is a dedicated ground so it should be the same reference point as the negative terminal of the battery. The TPS signal should be 0.6 to 1.0 VDC with the Key On Engine Off and the throttle closed. It should increase smoothly to ~ 5 VDC (VREF). Usually it tops out around 4.75 VDC.
If there is no VREF signal, you have bigger issues to deal with.
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I have 5 volts dc at the VREF but no signal from the tps even after cleaning the connectors and trying new sensors, what would cause the tps to have no signal if it’s 5 volts VREF and grounded 12 volts
Fleet Owner
Joined: Aug 2005
Posts: 23,667
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From: Easton,Ks
Sensor Signal Return (SIG RTN) should be zero volts or the same as the NEG post of the battery.
The voltage reference (VREF) voltage should be right at 5VDC with the key in the run position.
The Throttle Position (TP) wire voltage should be between 0.6-1.0 volts DC at closed throttle with meter neg hooked to SIG RTN.
Using a non loading volt meter (high impedance).
If your TP is zero volts with the key on, VREF at 5VDC you either have a harness with the TP wire shorted to ground or it is shorted to ground inside the EEC Computer.
The voltage reference (VREF) voltage should be right at 5VDC with the key in the run position.
The Throttle Position (TP) wire voltage should be between 0.6-1.0 volts DC at closed throttle with meter neg hooked to SIG RTN.
Using a non loading volt meter (high impedance).
If your TP is zero volts with the key on, VREF at 5VDC you either have a harness with the TP wire shorted to ground or it is shorted to ground inside the EEC Computer.
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Is there a certain test you can do to find out if it is the EEC that is bad ?
Sorry for all the questions guys I’m not much a whizz when it comes to this electrical stuff haha
Sorry for all the questions guys I’m not much a whizz when it comes to this electrical stuff haha
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