Honda PGM-FI Code 8: TP Sensor — Causes & Fix

Typical causes are a loose/corroded TP connector, a worn throttle position sensor, a misadjusted sensor, or damaged wiring. This is a generic Honda PGM-FI (Programmed Fuel Injection) code, so it applies across Honda FI models — scooters and underbones like the Click, Vario, BeAT, PCX, ADV, and Wave, as well as CB/CBR motorcycles. Honda shows it by blinking the FI/MIL warning light: a long blink counts as ten and a short blink counts as one (e.g. one long + two short = code 12). Clearing the code usually needs Honda’s service-check reset procedure (jumping the DLC service connector, or a scan tool) after the fault is fixed; simply resetting without repair will let the light return.

• FI/MIL light on with code 8
• Poor or jerky throttle response, surging
• Stalling when closing the throttle, or hanging idle
• Hesitation and reduced power

1. 1

   Inspect the TP sensor connector and wiring

   1. Locate the TP sensor on the throttle body. 2. Reseat the connector and check for corrosion or bent pins. 3. Inspect the harness for chafing near the throttle.

2. 2

   Check the sensor sweep

   1. Backprobe the signal wire and slowly open the throttle. 2. The voltage should rise smoothly with no dropouts; a jumpy or flat reading means a worn sensor.

3. 3

   Adjust or replace, then reset

   1. If the sensor is adjustable, set it to spec; otherwise replace it. 2. Clear the code and test throttle response.