Reed23

so I have been trying to find the codes for my 4runner, I have a 43 and a 52, does anyone know what they mean?

90 4runner v6 standard

abecedarian

43= starter signal (STA) not sent to ECU even after ECU determines engine RPM's at 800 or more
52= with engine between 1600-5200 RPM, no input to ECU from knock sensor for 6 crankshaft revolutions

That help?

abecedarian

43 suggests an issue in the wiring between the ignition switch and the ECU, or possibly that the truck has been started by 'bump' starting
52 suggests an issue with the wiring between the knock sensor and ECU, or possibly a knock sensor failure

Reed23

sweet, thanks a ton!!! now I just have to figure out why I have no starter signal back to the ecu, it starts up

abecedarian

find the STA wire to the ECU and check that it gets voltage while cranking. If I'm reading the diagram correctly, it should be a black wire with white stripe.

abecedarian

as for the knock sensor, that's another story.

sb5walker

Also you might check the ground between terminals E01/E02 on the ecu and the engine. Also check continuity between term E1 and a good chassis ground.