Remove the ECU cover (usually two screws or clips).
Without the suffix, a generic pinout is impossible.
Looking directly into the face of the female plug pins or the male ECU pins. toyota 89661 ecu pinout
If you are dealing with a rare JDM import or a modified harness, the safest way to verify pins is by opening the metal casing.
❌ – They are not. A 89661-02020 (MR2 Turbo) has a completely different pinout than a 89661-2F210 (Camry). ❌ Using a pinout for a different transmission type – Auto and manual ECUs swap several pins (neutral switch, PNP signals). ❌ Mixing up connector numbering – Some diagrams number left-to-right, others right-to-left. Look for a molded “1” on the connector. Remove the ECU cover (usually two screws or clips)
Below are representative pinouts for popular 89661-series units found in service manuals and technical papers.
Engine speed sensor (Crankshaft position sensor). If you are dealing with a rare JDM
Because Google cannot store pinouts for 200+ Toyota variants in one article, you need to know how to hunt for your specific diagram. Here are the three best methods.