NOTE: Refer to illustration for ECU connector and terminal identification. See Figure .

Turn ignition switch to OFF position. Disconnect throttle position sensor connector. Using an ohmmeter, check resistance between sensor terminals No. 1 (Red wire) and No. 3 (Black wire). Resistance should be 5000 ohms. Check resistance between sensor terminals No. 2 (White wire) and No. 3 (Black wire), while slowly opening throttle valve from closed position.
Resistance should be 10,000-12,000 ohms at fully closed throttle and 3000-5000 ohms at fully open throttle. Resistance should increase in response to throttle valve opening. If resistance is as specified, go to next step. If resistance is not as specified, replace throttle position sensor.
Disconnect ECU connectors. Using an ohmmeter, check resistance between ECU connector B60, terminal No. 1 and sensor connector terminal No. 3 (Black wire), between ECU connector B60, terminal No. 2 and sensor connector terminal No. 1 (Red wire), and between ECU connector, terminal No. 3 and sensor connector terminal No. 2 (White wire). Resistance should be zero ohms.
Check resistance between ground and connector terminals No. 1, 2 and 3. Resistance should be one meohm or greater at each terminal. If resistance is not as specified, repair appropriate circuit as necessary. If resistance is as specified, check ECU connector terminals for good contact. Repair as necessary. If connector terminals are okay, replace ECU.

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.

Safety Warning

Code 31: Throttle Position Sensor