PO7O4 Clutch Switch Input Circuit

**herculesrider1** · 05-18-2019, 08:13 PM

My Service Engine Soon light comes on and it's PO7O4. Clutch Switch Input. I crawl under the dash and see that the previous owner cut the wires and twisted them together. The circuit was always made, and you could start the car without depressing the clutch. I resoldered the wires back together, bought a new switch, the black one, installed it, reconnected the connector, and now you can't start it without depressing the clutch pedal, the way it should be. However, the SES light just came back on with the same code, PO7O4. If the clutch switch will not allow the car to start unless the clutch is depressed, it must be working, then how can the code come back stating that something is wrong with the clutch switch. If it wasn't working correctly, it would not start, even if you depressed the clutch. Scratching my head on this one...

**jaboc** · 05-19-2019, 07:16 AM

Originally Posted by herculesrider1

My Service Engine Soon light comes on and it's PO7O4. Clutch Switch Input. I crawl under the dash and see that the previous owner cut the wires and twisted them together. The circuit was always made, and you could start the car without depressing the clutch. I resoldered the wires back together, bought a new switch, the black one, installed it, reconnected the connector, and now you can't start it without depressing the clutch pedal, the way it should be. However, the SES light just came back on with the same code, PO7O4. If the clutch switch will not allow the car to start unless the clutch is depressed, it must be working, then how can the code come back stating that something is wrong with the clutch switch. If it wasn't working correctly, it would not start, even if you depressed the clutch. Scratching my head on this one...

A similar thing happened on my s10... check the actual range of the sensor.. meaning when you push the clutch to the floor, it complete a circuit that lets you start the car. The sensor also recognizes when the pedal is at the top. Your car probably thinks the clutch is being pressed all the time, even though the clutch is mechanically working flawlessly. I had to shim my clutch sensor out a bit so the SES light would go off.

This might not be relevant for this application but it’s a good place to start.

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**herculesrider1** · 05-26-2019, 03:54 PM

Originally Posted by jaboc

A similar thing happened on my s10... check the actual range of the sensor.. meaning when you push the clutch to the floor, it complete a circuit that lets you start the car. The sensor also recognizes when the pedal is at the top. Your car probably thinks the clutch is being pressed all the time, even though the clutch is mechanically working flawlessly. I had to shim my clutch sensor out a bit so the SES light would go off.

This might not be relevant for this application but it’s a good place to start.

Sent from my iPhone using Tapatalk

I will get under the dash and look at the depth the switch gets depressed to. Thanks for your reply Jake!