TPS Problem

[Comrade]

TPS Connection Problem: My TPS shows 100% throttle with the car not on, When I take off the harness it says 0%.

Bought a new TPS, I connected the TPS harness to the new TPS (Not mounted on the throttle) and again it shows 100% and when I unplug the harness it drops to 0%.

Could it be my harness to the TPS or my boomslang?


My Original Thread: http://www.3si.org/forum/f35/vr4-won...eo-log-528787/

[x2xtreme360]

Have you tested the wiring as I suggested? I knew you were going to buy a new TPS without doing the cheap stuff first.

It sounds like a faulty ground at the TPS. Have you checked that? If it goes to 0 when you unplug the TPS, it's almost a certainty that you don't have any shorts.

Check the sensor ground at the TPS.

[Boost4VR4]

Did you install it correctly? You can install them upside down I suppose, since they are symmetrical...

[x2xtreme360]

Did you install it correctly? You can install them upside down I suppose, since they are symmetrical...

Not a possibility. If the connector were flipped, the PCM would still not see a reading, as pins 2 and 3 on the connector would be swapped, and pin 3 isn't used on the wiring harness.

[Comrade]

Have you tested the wiring as I suggested? I knew you were going to buy a new TPS without doing the cheap stuff first.

It sounds like a faulty ground at the TPS. Have you checked that? If it goes to 0 when you unplug the TPS, it's almost a certainty that you don't have any shorts.

Check the sensor ground at the TPS.

Where is the sensor ground at the tps?

[RealMcCoy]

The sensor return ground goes back to the ecu at pin 72. The ECU grounds from pin 71 out to the ground connection under the wiper motor.

[RealMcCoy]

I would check the actual voltage from the TPS.If it's at 5V as the scan data indicates, then continue to chase the electrical issue... If not, then you could be looking at an ECU issue.

[RealMcCoy]

Did you install it correctly? You can install them upside down I suppose, since they are symmetrical...

It only plugs on one way...

and pin 3 isn't used on the wiring harness.

Pin 3 is the idle switch.

[x2xtreme360]

I would check the actual voltage from the TPS.If it's at 5V as the scan data indicates, then continue to chase the electrical issue... If not, then you could be looking at an ECU issue.

The reference voltage? If the voltage drops back down to zero at the signal line when he unplugs the TPS, it's very doubtful that he's got a short of any type.

What I would do is check the 5V. Verify the sensor has a good ground. Then disconnect the harness at both the TPS and ECU, check continuity at the PCM and verify once and for all that no shorts are present between the 3 pins.

It only plugs on one way...



Pin 3 is the idle switch.

Not sure what the idle switch is for, but it showed vacant in the wiring diagram.

[RealMcCoy]

The reference voltage? If the voltage drops back down to zero at the signal line when he unplugs the TPS, it's very doubtful that he's got a short of any type.

I wasn't disagreeing with you, your thinking is sound, I was just suggesting he confirm 5v (100%) on the signal wire, rather than assume it's there from scan data.

Not sure what the idle switch is for, but it showed vacant in the wiring diagram.

What diagram? I don't think I've seen that one... The idle switch is how the ECU determines closed throttle.