P2038: Reductant Injection Air Pressure Sensor A Circuit Range/Performance
What to do
Worth attending to promptly. Ask whether the injector and its lines were checked for crystallised deposits — that is the usual restriction, and it builds up further while the fault is left.
What this code means
The reductant injection air pressure reading is electrically valid but does not match what the system should be producing. A pressure lower than commanded points at a leak or a restriction in the air path; one that does not change when dosing is commanded points at the sensor or at an air supply that is not being switched on.
Crystallised deposits are the restriction to suspect first, because they are both the commonest cause and the one that gets worse while a diagnosis is postponed.
Likely causes
Start here
- Crystallised reductant deposits · specialist
- Restricted reductant injection air line · moderate
- Faulty reductant injection air pressure sensor · moderate
Less common
- Air leak in the reductant delivery system · moderate
- Faulty reductant injector · 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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