jjknott82

Hi, I'm Jacob and I've tried everything and can't figure out the problem. Can someone please help!!!

I have a 2003 Honda Accord EX, 2.4L. I keep getting a check engine light for Throttle Position Sensor (TPS codes P0122 & P1121). Also the car keeps jumping, it dips down real low in RPMs for a few seconds and then gains it back. It does this every minute or so. I have 5 volts coming in to the TPS but don't have any volts reading at the signal out lead. I have replaced the TPS twice and it hasn't fixed the problem. If I unplug the harness from the TPS sensor and run a test wire from the 5 volts harness wire to prong on TPS and the negative to its prong I get 4.5 volts coming out of sensor and 5 volts when I accelerate indicating that the TPS is working, but as soon as I plug the harness back into the sensor I lose all volts coming out of sensor. I've also tested connectivity for the signal out line from the plug to the end of harness and I have no brakes in the line. Can someone else tell me what's wrong or what to test next?

Jlmejia316

Check for continuity between the 5V reference and TPS Signal wire with the TPS and PCM disconnected. If you have continuity between the two circuits than you have found your problem. You can try and find the source of the short or you can attempt to perform an overlay of the affected circuits. Make sure to also check the terminals in the connectors for any damage that may cause a loss of signal to the PCM.

If you can't find any circuit issues and still think there is a circuit problem, I would recommend performing a temporary overlay of all circuits between the TPS and PCM. If your concern is no longer present, make the overlay permanent. If the concern is still present, replace the PCM.

tech8

Based on your description, it sounds like the sensor ground (-) may not be at the TPS harness connector's Yel/Grn wire. You may have to backprobe the TPS wires. Backprobing is either using a backprobe set or using a thin needle or something and making contact with the metal terminal of the connector without piercing the wire in the back of the still connected connector. Care must be taken to ensure that the wiring does not get damaged. You can use something like a T pin, available at Walmart, etc., and backprobe.

1. Turn the ignition switch ON (III).
2. With a voltmeter, backprobe by touching the voltmeter's red lead to the Yel/Blu wire (terminal no. 3) and the voltmeter's black lead to the Grn/Yel wire (terminal no 1). Is there about 5 volts? If not, touch the voltmeter's black lead to body ground, is there now about 5 volts?