Code result
P2688
Fuel Supply Heater Control Circuit Low
Moderate severity
What it means
Voltage on the fuel supply heater control line is below the expected window. The sensor heater warms the element to operating temperature (~600 °C); without it the lambda sensor stays inactive in closed loop and the ECM cannot trim mixture.
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
Control wire shorted to ground
highOne of the most commonly reported causes for this code — check this first.
Relay coil short
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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