Hello,
My first ?modern? fuel injected ecu controlled car and here I am.
I have a 96 Seat Cordoba which is running badly (erratic idling, loss of power, misfire, intermittent stoppage). Fault code reader gave ?throttle position sensor faulty?. I replaced the tps with a secondhand unit. Now the code given is ?throttle position sensor no signal?. The voltage at three of the six pins on the tps plug measures around 12 volts with the plug disconnected. I believe it should be no more than 5v. With the plug connected to the tps the voltage varies erratically between 2.6v and 12v as the throttle is operated.
I?m thinking the problem may be the voltage rather than the tps unit itself and I don?t want to buy a new tps unnecessarily. Has anyone had a similar experience?
(The car has single point injection. Voltage across the battery, and at the other sensors seems normal. The ECU has been tested OK and the car has had new plugs, leads, lambda sensor and secondhand coil. The Cat has also been recently replaced).
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Hi sb,
Cordoba has several different specs and management systems, but in all cases that I can find the supply voltage to the TPS should be 5.0v. The signal specs vary a bit, but all are around 0.5v with throttle shut and around 4.5v fully open. Obviously, these are readings with the harness connected. The critical thing is that the rise in signal as the throttle opens should be absolutely smooth and progressive - to test this you really have to look at it on an oscilloscope. TPS faults are quite common on these, as are coil/amplifier problems. A modified coil/amp assembly was introduced with the two slightly separated (but still in unit) to allow better cooling of the amp.
Regards, Adam
Whatever is rightly done, however humble, is noble.
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Thanks for that Adam. could a fault in the tps unit itself could affect the supply voltage? And if the coil was suspect would other voltages at the throttle body (injector etc) be affected also?
(Car is 1.6 with Bosch Mono Motronic engine management).
SB
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A TPS fault will not effect supply voltage, but I am not sure which pins you are measuring here - you really need to view a diagram of the connector to see which are supplies and which are signals or earths. Not being rude, but are you quite sure you are examining the TPS, as there may be a Stepper Motor/Idle Switch on the other side of the throttle body, usually 4 pins but some are also 6 !!
No, a suspect coil is not going to effect the TPS etc - I just mentioned it as it is a very common fault on these.
Once again, there is a strong case here for investing in a bit of professional assistance before commiting to expensive components.
Regards, Adam
Whatever is rightly done, however humble, is noble.
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