Code 23, Throttle Position Sensor MISADJUSTED: Notes

1990 Chevrolet Chevy Van G20, 6.2 C, 4L60/MD8SECTION Notes

The Throttle Position Sensor (TPS), a variable resistor, informs the ECM of throttle opening. The TPS, connected to a 5-volt reference signal, has a high resistance value at closed throttle. At wide open throttle, TPS resistance is at its lowest and output to the ECM will be close to 5 volts. Code 23 means the ECM has seen the following: voltage is not .25-1.35 volts at ECM terminal A2 for at least 30 seconds at 550-650 RPM.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Test Number 1)  This confirms Code 23 and fault are present.

Test Number 2)  This test determines if sensor signal line is shorted to ground.

Test Number 3)  See THROTTLE POSITION SENSOR in N - REMOVE/INSTALL/OHAUL.

RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.