Cause
Blocked or split pressure sensing hose
The thin hoses that carry exhaust pressure to a sensor mounted safely away from the heat — the particulate filter's differential pair being the classic case. They are the measurement's weakest link: soot slowly plugs them, heat splits them, and after any exhaust or filter work the pair can be refitted swapped, which reverses the reading's sign while everything measures electrically perfect.
A blocked hose produces a believable wrong number, not a dead signal — which is why this cause outranks the sensor on most of the codes that list both, and why it is the specified first check whenever a pressure reading stops tracking the engine. The repair is minutes and pennies; the misdiagnosis it prevents is a sensor at best and a condemned particulate filter at worst. After exhaust work, "were the hoses swapped?" is the first question, not the last.
Typically an easy fix. Often worth checking before paying anyone to look.
Codes this can cause (8)
Codes where this is a likely explanation first, rather than merely a possible one.
- P2452 Particulate Filter Pressure Sensor A Circuit Likely for this code Moderate
- P2453 Particulate Filter Pressure Sensor A Circuit Range/Performance Likely for this code Moderate
- P2464 Particulate Filter Differential Pressure Too Low — Bank 2 Likely for this code Moderate
- P0401 Exhaust Gas Recirculation A Flow Insufficient Detected Moderate
- P2458 Particulate Filter Regeneration Duration — Bank 1 Moderate
- P2459 Particulate Filter Regeneration Frequency — Bank 1 Moderate
- P2463 Particulate Filter Restriction — Soot Accumulation — Bank 1 High
- P2465 Particulate Filter Differential Pressure Too High — Bank 2 Moderate
Information, not instruction
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