Diagnostic article Generic OBD-II
P0840: Touareg hydraulic-pressure sender G193 circuit
Volkswagen P0840 directs diagnosis to transmission hydraulic-pressure sender 1 and its wiring.
Read before applying this article
Documented application
2004 Volkswagen Touareg (7LA), V10 5.0L diesel BKW; original diagnostic chart and component procedure; confirm installed transmission where relevant.
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.
In the BKW Touareg service collection, P0840 is assigned to transmission hydraulic-pressure sender 1, G193. The generic title calls it pressure sensor/switch A. Volkswagen directs the hydraulic-pressure-sensor electrical procedure rather than declaring a particular physical line pressure too high or low.
Establish the test prerequisites
The procedure requires valid transmission grounds, appropriate fuses, battery voltage of at least 11.5 V, the selector in Park, and ignition off. These conditions define a controlled wiring assessment; they are not a pressure-operating specification.
The test checks continuity between the transmission-controller wiring and the identified eight-pin connection, using a maximum conductor resistance of 1.5 ohms. It separately checks for shorts between wires. Correct continuity alone therefore does not establish that adjacent conductors remain electrically isolated.
Sensor replacement follows the wiring branch
Volkswagen directs replacement of the relevant pressure sender if the wiring checks reveal no fault. That sequence makes an external circuit defect a meaningful alternative to a failed sensor.
The chart does not publish a sensor signal voltage, pressure threshold, or hydraulic gauge comparison for P0840. A pressure value derived from a faulty electrical input cannot by itself establish actual hydraulic pressure.
Verification should address G193's measurement circuit using the exact installed transmission information and then complete the prescribed memory/readiness steps. Pressurized transmission-system work requires the applicable professional procedure; this code is not a reason to loosen a hydraulic connection merely to assess pressure by observation.
Source and applicability
Volkswagen diagnostic chart, P0840. 2004 Volkswagen Touareg (7LA), V10 5.0L diesel BKW; original diagnostic chart and component procedure; confirm installed transmission where relevant. These values describe that documented monitor; they are not universal specifications for every vehicle displaying this code.
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
Transmission Fluid Pressure Sensor/Switch A Circuit
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