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Relay Runaround on Toyota Models
A faulty main circuit opening relay may cause an intermittent no-start condition on several Toyota models. If you are lucky enough to get the vehicle from the customer when it won't start, try this simple check before you waste any time on complicated diagnosis:
- Turn the ignition to the ON position. The CHECK ENGINE light should be ON.
- If the CHECK ENGINE light is not ON, locate the main circuit opening relay, then make sure you have more than nine volts on the output pole of the relay with the ignition in the ON position.
- If the output voltage is below nine volts, but the input voltage to the relay is equal to battery voltage, replace the circuit opening relay. Its internal contacts are probably pitted and arced, which creates a voltage drop inside the relay.
I've spent more than one day on more than one car, trying to find an intermittent relay. Now I check the CHECK ENGINE light before I do any further diagnosis.
Brad Foltz
Miller Auto Group
Hedgeville, West Virginia
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