QuestionHello, My 92 toyota p/u sat for 3 months. then displayed codes 12,13,21,&43 the ck engine lite is on....truck has 160,000 miles 20k since tune up. help??
thanks
AnswerThe list below contains the information for each code:
Code 12- RPM signal. No "Ne" signal to ECU within 2 senconds after engine has been cranked. Trouble areas include: distributor or distributor circuit, starter signal circuit, igniter or igniter circuit, ECU.
Code 13- RPM signal. No "Ne" signal to ECU within several msec. after the engine speed reaches 1,000 or 1,500 RPM. Trouble areas include: distributor or distributor circuit, ECU.
Code 21- Oxygen sensor signal. Open or short in oxygen sensor signal, detection of oxygen signal deterioration (this sometimes happens when you had or have a broken head gasket) Trouble areas include: oxygen sensor circuit, oxygen sensor, ECU.
Code 43- Starter Signal: No "STA" signal to ECU until engine speed reaches 800 RPM with vehicle not moving. Trouble areas include: Ignition switch circuit, ignition switch, ECU.
In most cases, it's usually the sensor that's faulty. It's unlikely that there's an "open" in any of these circuits but it is possible. You can obtain a wiring diagram from your local library to trace the circuits to be sure. Before you do, follow these steps to erase the codes stored on your ECU: remove the NEGATIVE battery cable, let stand for no less than 60 seconds, then reconnect. If the engine light re-appears, pull the codes again and see which ones are still there or which ones disappeared.
