code p1121

So I have this code and it came up after some wiring was done in my car to take the alarm off.

It is neutral position switch circuit low input for an automatic transmission on my 97 legacy gt. I was wondering if anyone has had this code before and fixed it or went to a shop and got it fixed.

I've looked on here to see if anyone has had it but I don't find anything.

I have also tried to figure out what exactly it means and what's going on but never anything specific.

Is the vehicle running fine aside from the code?

Yeah it runs the same as before. So that's why I haven't made it a priority to fix but I do want to get rid of it soon

You can always disconnect the battery for 10-20 minutes and pump the brakes to get any electricity out of the system to reset the ECU and see if the code goes away.

 

On my turbo legacy I had a code for the neutral position safety switch. It didn't affect anything but I replaced it anyway and the code went away.

 

It is a switch on the side of the 4EAT that connects to the shifter cable. They are easy to swap out and not too hard to adjust.

 

Junkyard is the best bet for a cheap one otherwise a new one is $125 last time I checked.

 

If you have a multimeter you can check the switch following this protocol:

"DTC P1121 (N_SWON): NEUTRAL POSITION SWITCH CIRCUIT LOW INPUT (A/T)

1. If DTC P0705 is present, diagnose DTC P0705 first. See appropriate article in the TRANSMISSIONS

section. If DTC P0705 is not present, turn ignition on. Using DVOM connected to chassis ground,

backprobe ECM connector terminal No. 82. See appropriate wiring diagram in L - WIRING

DIAGRAMS article. If voltage reading is 4.5-5.5 volts, in other positions (not neutral), circuit is normal.

Check all connections. If voltage reading is not 4.5-5.5 volts, go to next step.

2. If inhibitor switch has plastic body, go to next step. If inhibitor switch does not have plastic body, go to

step 7).

3. Turn ignition off. Disconnect ECM and transmission connectors. Check resistance between ECM

connector terminal No. 82 and ground. If resistance is less than 10 ohms, repair short in wiring. If

resistance is 10 ohms or more, go to next step.

4. Disconnect inhibitor switch connector. Check resistance between transmission connector terminal No. 11

and ground. If resistance is less than 10 ohms, repair short in wiring. If resistance is 10 ohms or more, go

to next step.

5. Check resistance between inhibitor switch terminal No. 1 and No. 2. If continuity does not exist in other

positions (not neutral), go to next step. If continuity exists, replace switch.

6. Check selector cable and connection to inhibitor switch. Repair or replace as needed.

7. Turn ignition off. Disconnect ECM and transmission connectors. Check resistance between ECM

connector terminal No. 82 and ground. If resistance is less than 10 ohms, repair short in wiring. If

resistance is 10 ohms or more, go to next step.

8. Check resistance between transmission connector terminal No. 11 and No. 12. If continuity does not exist

in other positions (not neutral), go to next step. If continuity exists, replace switch.

9. Check selector cable and connection to inhibitor switch. Repair or replace as needed."

the alarm system will not let you start the car if it is in alarm.

the remote entry system will let you start the car when it is in''alarm''.(it will flash the parking lights)

 

since this is the result of removing the alarm system,

i think it is a wiring problem,

not a neutral safety switch problem.

 

so i would keep that in mind.

frankly i'm surprised you can even start the car.

Johnegg yeah I took the alarm off because one night the alarm wasn't letting me turn the car on. So what I need to do is take a look at the area where the wiring was done?

Its weird because for some odd reason a few weeks ago I started the car up and when I revved the car it would make the alarm noise. I don't know how or why that would happen.

And thanks monkeyposeur for all the information. Much appreciated.

I also have had the same issues with my alarm system. It comes on whenever park lights flashing and the engine won't start. So on You Tube, I saw a way to bypass alarm getting rid of flashing park lights and allowing the engine to start. Worked great but now I have an engine light and excessive fuel consumption. Engine light code is p1121. What is the fix on this? How should I have dealt with the faulty alarm system? I would, like to very much get my fuel mileage back. Just bought the car but before I applied "the fix" it seemed to get better mileage. Now I get 20MPG and I need to smog but have this p1121 code.