I have a 2001 Toyota Camry 2.2 that i replaced its engine recently. I went for a drive after filling the fluids and came home and shut it off and it never started after that, it throws P1780 code (neutral / park position safety sensor). I checked the wiring harness in the trunk and i can see no issues. The 3rd stop light it in the middle had a blown light that i changed and the issue persisted. I took off neutral/park position sensor and cleaned its connection and the inside of it and still the same issue, the car doesn?t crank on park nor on neutral. Any ideas?

 

Does the gear shifter position match the gear indicator light position?

When the gear shifter is in Park or Neutral check for continuity between the black/white wire and gray wires of the switch.

 

Thank you for your input. Yes the gear shifter matches what?s on the dashboard.

yes i will need to grab my voltmeter and test that thank you.

Update: i went to picknpull and got a used ECM and a park/neutral position sensor. Changed both and the issue still here, i checked the main harness that passes above the intake manifold and noticed a burn from the EGR pipe, i took off the harness and found one wire that looks cooked (it matches one of the PNP sensor wires) did a jumper wire and the issue still there!

 

The ECU knows when the safety switch is in P or N because a 12v signal is sent to the STA terminal of the ECU. No signal means the code is set. Could be a bad ECU but check other areas first,

The start safety system (P/N switch safety switch) and selected gear switch for dashboard gear light appear to use separate fuses. The start system uses a 5A STARTER fuse. The dashboard lights used the 10A GAUGE fuse. Check 5A fuse.

12v goes to the START fuse then P/N safety switch to a junction box then STA terminal. There may be an issue with this circuit.

If you want can jump the starter solenoid wire with 12V. This is the small wire on the solenoid. Make sure the trans is in park.

 

thank you! yes the starter fuse was blown. I guess there was initially a PNP switch issue but then the fuse got blown as i was trying to crank the engine many times its basically the same symptoms that?s why i didn?t know that the initial issue got resolved. But it?s worth mentioning that after i changed the PNP and the ECM i couldn?t see the P1780 code on the OBD anymore.


I really appreciate your helpful comment. It clicked and it was the only thing i didn?t check.

 

Great job!

Glad to help!