Jim V

Hi, I got the pleasure of working on my step fathers car and I pulled up dtc p1780 with my scanner so assumed it was the park /neutral sw. so 229 dollars later I have the same problem. Heres where it gets interesting Everything works correctly according to my scanner until I push down on the brake and the scanners is saying reverse is engaged.The light on the dash comes on saying its in reverse. I'm Leaning towards the ecu now????? dont want to spend alot of money on another part and not fix it. any help would be great. thanks,Jim V

ctwright

Do you have the same problem without the scanner hooked up?

Jim V

Yes the problem is still there when the scanner is not hooked up.I even disconnected the park neutral switch and step on the brake and the reverse light comes on when its in P N D 2 L.

ctwright

I would think park/neutral switch would be a safety switch to prevent starting the vehicle other than in park and neutral. Does the vehicle also have a reverse light back up switch or is it all combined into the switch you are talking about?

Jim V

I proped a flash light on the brake and the revese lights on the back of the vehicle dont come on but the light in the instrument cluster is on and the scanner is saying reverse is engaged while your in any gear with your foot on the brake pedal.

Mike Gerber

"I proped a flash light on the brake and the revese lights on the back of the vehicle dont come on but the light in the instrument cluster is on and the scanner is saying reverse is engaged while your in any gear with your foot on the brake pedal."

It is always helpful to list the year of the car, which engine, how many miles are currently on the car and what if any maintenance has been done to the car recently.

That said, it is common on all Camrys to have problems with the loom of wires inside the trunk, attached to the driver's side trunk hinge. That loom is subjected to a lot of flexing, each time the trunk opens and closes. Eventually some of the wires inside that loom fray and break. I would start looking for a problem there. Open that loom of wires and look for frayed or broken wires. Repair what you find.

Mike

Jim V

I found the problem Yesterday!!! Before I read mikes answer but you where dead on right. Three wires in the trunk hinge area shorted together on being the ground the brake and the reverse light circuit.Needless to say when I pushed on the brake it energized the reverse light on the instr. cluster and telling the ecm that the shifterwas in rev. I eliminated the ecm because I had the ecm totally disconneted and still had the problem so I knew it had to be wiring and I remember my step father saying he was having problems with his lights on his trunk Duhhhhhhh!!! thats when it hit me. Thanks for the help Hope this will Help someone else because I was pulling my hair out and its getting thinner everyday.

zdpq

Hello All,

I had a similar experience with my mom's 2000 Camry LE. 3.0L V6 with 131,000 miles, automatic transmission. The symptoms were as follows:

1. Check Engine was lit on the dashboard panel. ODBII code of P1780.

2. The R (reverse light) on the dashboard would light up each time you hit the brake and go away when you released the pedal (in all gears except Park or Reverse).

3. Dashboard panel also had a lit symbol of the vehicle that indicated that something was wrong with the rear lights (the symbol actually did not appear until you press on the brakes after starting the car each time and stayed on until you turned off the car). The rear lights were functioning properly.

4. Whenever you brake after driving at least 30 MPH, the car would shudder just before coming to a full stop.

Had all the brake pads changed on all 4 wheels just 4 days before this all started. Took the car back to the mechanic who found the same code of P1780. He stated that the problem was with the tranny. He said two valves were stuck open and that they caused this code. Report from mechanic said that the tranny fluid was burnt and needed to be flushed and replaced.

I did some research myself and found this forum and your guys post. This led me into the right direction. My brother is a smog technician and together we checked the wiring harness in the trunk but did not find any frayed wires. We then physically inspected the rear brake bulbs (remember that they were functioning properly). On the passenger side bulb, we noticed a black hue to the bulb similar to how a burned out bulb looks.

On a whim, we swapped out this bulb and voila, the check engine light disappeared. I turned off the engine and restarted the car and the symbol for a problem with the rear lights did not come on when I pressed on the brake pedal and the check engine remained off.

We took the car for a drive and the shudder was gone. My brother summized that the bulb was causing the P1780 code perhaps because of a drop in resistance and the ECM interpretted this incorrectly.

So thank you all for posting. I hope that this helps someone else with this issue.

JOET/CAMRY

Is that crazy or what. A defective light bulb was to blame for all that havoc. Congrats on fixing the problem.

Regards,
JOET/CAMRY

GSS123

Great thread with helpful information. Thanks guys