Diagnosed a bad throttle position sensor. Installed a new one. Ran great for about a minute. Went back to running rough. Installed another new tps. Again it ran good for about a minute. Then it ran rough again. With the voltmeter I confirmed I had good 12 volt power going in. On the third wire I confirmed a good ground loop. But on the signal wire it should read 0.9 volts on closed throttle and 5.0 volts on wide open throttle. It gave 0.3 volts closed throttle to wide open throttle. Could my signal wire be grounded somewhere? Or could my computer be fried?
Throttle Position Sensor
Testing for short or open in wiring harness
Check TP Circuit for open in harness
- Turn ignition switch to off position. Leave TP sensor disconnected. Disconnect PCM connector(s). Inspect connector for loose, damaged or corroded terminals, and repair as needed.
- Using a digital multi-meter, measure resistance of TP circuit between PCM harness connector and TP sensor connector.
- If resistance is less than 5 ohms go to next step below. If resistance is 5 ohms or more, repair open in TP circuit.
Check TP Circuit for short to SIG RTN or PWR GND in harness
- Ensure PCM is disconnected. Disconnect scan tool from Data Link Connector.
- Using a Digital multi-meter, measure resistance between TP circuit, and SIG RTN and PWR GND circuits at PCM harness connector. If either resistance measurement is 10k/ohms or less, repair short between circuits.
- If both resistance measurements are more than 10k/ohms, replace the PCM.