OBD codes 1120 and 1121



1998 sc300 96,000 miles

While driving, engine got real quiet.

I pulled over and asked “is it running”?

Yes, tachometer said around 1000 rpm.

Check engine light was lit up.

Pressed accelerator and nothing happened.

Floored accelerator and rpm jumped to 2000 rpm.

Limped home jumping from 1000 to 2000 rpm depending on street conditions.

At home, obd codes 1120 and 1121 were found. These have to do with throttle and gas pedal position sensors.

Measured resistances of sensors as indicated in service manual; both sensors measured OK.

Pushed the connectors in and out repeatedly to break up any corrosion on the pins.

Cleared the codes.

Car runs perfect again.
Oh well, it is 23 years old !!!!!!

 

Well it drove ok for a day, and then code 1120 popped up again.
I am following the repair instructions on youtube
I will let you know how it goes.

 

I'm glad you posted this and will be curious about the results! It's nice to know these can be repaired to some degree.

 

The above video repair is good in the middle, but wanting in the beginning and end.

Let’s fill in some of the blanks.

Mine is the 2jzge version, so the APPS (accelerator pedal position sensor) is harder to get at than the turbo models.

Picture13


Disconnect the battery.

Loosen the accelerator cable nut on the left side of the car. Lift up the cable from the support.

Remove the cable from the accelerator pulley.

Remove the two 12 mm bolts holding down the cable support bracket. Note the leverage extender in the following picture

Picture6


Remove the cable support bracket.

There are 4 8mm bolts holding the APPS to the housing. The top two are easy to wrench off.

The bottom two are a bear to undo.

They have a washer plate with tangs to prevent the bolts from turning.

First thought is to unbend the tangs, but this looks difficult in that tiny area.

Put a thin rag under the area to prevent dropping small parts down in the spark plug valley (I did that).

Picture9


If you turn the bolts with the phillips , those tangs will bend out of the way. Use a stubby #2 phillips screw bit and a ¼ inch open wrench to turn the bit.

Picture4


The APPS can then be lifted off.

Note that the 4 bolts have lock washers and lock-tight on them.

Use a Dremel cutter like the following to open the white case.

Picture2


Picture1


The previous repair video completes the middle of this job.

I used the liquid insulation to prevent oxidation of the solder joints.

Picture3


Picture8


I didn’t like having Phillips bolts on the bottom, so I replaced them with two allen bolts and lock washers (m5-.8x12) ($.75 each at Ace Hardware).

The washer plate is now useless and deleted, since allen bolts have no faces on the head.

The service manual says to torque these to 13 INCH pounds. This is nearly nothing, since they are tiny fine thread bolts into aluminum.

I felt what 13 inch pounds felt like and turned the wrenches to match.

Reassemble the support bracket, mount the cable, and tighten nut.

Plug connector back on.

Reconnect the battery and start the car.



Car works again, but you can only be certain it’s fixed, one year later!!!!