Code result
P2040
Reductant Injection Air Pressure Sensor A Circuit High
Moderate severity
What it means
The reductant injection air-pressure sensor A reads above its upper plausibility limit — open signal line or short to B+.
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
Open signal line
highOne of the most commonly reported causes for this code — check this first.
Connector pins corroded - high contact resistance
lowLess common, but worth ruling out after the more likely causes.
Supply wire pinched against B+ source
lowLess common, but worth ruling out after the more likely causes.
Related help
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