Diagnostic article Generic OBD-II
P2712: CW6A-EL hydraulic support during i-stop
The documented Mazda P2712 procedure covers cW6A-EL hydraulic support during i-stop.
Read before applying this article
Documented application
Mazda3 workshop manual 01/2019 onward, d9n1-1a-22d_ver10; TCM (CW6A-EL). Verify exact vehicle specification; this is a Mazda application example.
The code alone does not identify a failed part or establish that a vehicle is safe to drive. Confirm the vehicle, reporting module and applicable service procedure.
P2712 is cataloged as hydraulic power unit leakage. Mazda's CW6A-EL source describes an oil-pump shift valve that is stuck, detected through missing pressure-switch confirmation during i-stop.
Monitor the stopped-engine hydraulic event
The documented condition is oil pressure switch number 1 remaining off for ten seconds while the electric AT oil pump operates during i-stop, with D or N selected. The pressure switch, low clutch and range sensor must be normal, and the rate-of-speed-change condition must be satisfied.
This is a hydraulic support test during an engine-stop state. It is not a direct observation of fluid leaking outside the transaxle. Mazda lists the hydraulic passage switching valve in the control valve body and the electric AT oil pump as possible causes, then inhibits i-stop.
Why an ordinary idle check may miss it
The confirmation sequence includes driving in second gear or higher and subsequent i-stop operation, repeated under the specified conditions. A vehicle that never enters i-stop has not reproduced the relevant event merely because it idles without a code.
The factory unresolved-fault branch addresses the control valve body and electric pump. That direction should be applied only after confirming the exact transaxle, service information and repeatability. The general leakage label and Mazda's stuck-valve wording are retained as an applicability distinction, not silently treated as proof of an external hydraulic leak.
Documented application
Mazda3 workshop manual 01/2019 onward, d9n1-1a-22d_ver10; TCM (CW6A-EL). Verify exact vehicle specification; this is a Mazda application example. Mazda factory diagnostic page, mirrored by CHARM.
Article source documents
Source checks describe how the text was prepared; they do not certify a diagnosis or confirm compatibility with every vehicle using this code.
Original code reference
Dictionary definition
Hydraulic Power Unit Leakage
This definition retains its original catalog scope. The article above is limited to its explicitly documented application.
Reference scope
Generic OBD-II definition.
A manufacturer label does not establish the model, year, engine or module to which a diagnosis applies. Read the safety and diagnostic limits.
Definition source
- DTC Database: pinned community code definitions
Source checked · MIT