Code result
P0688
ECM/PCM Power Relay Sense Circuit / Open
Moderate severity
What it means
ECM/PCM Power Relay Sense Circuit High: the signal voltage is above the expected range. Often an open circuit or a short to supply voltage.
Is it safe to drive?
Use caution
The vehicle is usually drivable for short distances, but the problem can worsen or affect emissions. Diagnose and repair as soon as practical.
Most likely causes
Main relay contacts stuck closed
highOne of the most commonly reported causes for this code — check this first.
Sense wire shorted to power
mediumA plausible cause — test and verify before replacing parts.
Connector pins corroded - high contact resistance
lowLess common, but worth ruling out after the more likely causes.
Related help
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