P2041: Reductant Injection Air Pressure Sensor A Circuit Intermittent
What to do
Worth attending to sooner than an intermittent fault normally deserves. Each interruption to dosing leaves deposits behind, so the fault is quietly making itself worse while it is left.
What this code means
The reductant injection air pressure signal drops out or jumps briefly. Because the module uses it to confirm the dose is being atomised, an unstable reading causes dosing to be suspended and resumed repeatedly — and every suspension leaves a little more undispersed fluid in the injector to crystallise.
That makes an intermittent fault here worse than its name suggests: it is not merely unreliable reporting, it actively contributes to the deposit that eventually blocks the system.
Likely causes
Start here
- Corroded or loose connector · easy
- Road damage to underfloor wiring · moderate
- Faulty reductant injection air pressure sensor · moderate
Less common
- Crystallised reductant deposits · specialist
Symptoms
Components involved
Information, not instruction
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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
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