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Differential-pressure sensor

Differential-pressure sensor: Driveline ratio can be tracked from input speed / output speed; mismatch between commanded gear and achieved ratio can indicate slip or a speed-sensor problem. The page also includes a worked example and measurement sequence.

6 concrete technical facts1 worked example4 sources

Technical frame

Differential-pressure sensor: Driveline ratio can be tracked from input speed / output speed; mismatch between commanded gear and achieved ratio can indicate slip or a speed-sensor problem. The page also includes a worked example and measurement sequence.

The technical values here expose the standard, protocol or physical relationship directly; model-specific service values are linked through the matching model/variant dossier.

The goal is not only to define the term but to let the reader calculate and interpret what the data means in a scan, scope or physical test.

Concrete technical facts

  • Driveline ratio can be tracked from input speed / output speed; mismatch between commanded gear and achieved ratio can indicate slip or a speed-sensor problem.
  • With torque-converter lock-up applied, engine-to-turbine slip normally becomes small; the exact acceptable range is transmission/condition specific.
  • In a DCT, clutch fill/adaptation values connect electronic command with actual mechanical clutch behavior.
  • A CVT continuously varies input/output ratio, so a displayed “gear” should not be interpreted like a stepped planetary automatic.
  • Transfer-case/differential diagnosis should consider tire circumference, wheel speeds, lubricant and mechanical preload before blaming electronics.
  • Transmission temperature changes viscosity and pressure behavior, so target/actual comparisons need a comparable temperature window.

Worked example

  • Ratio example: 2400 rpm input and 800 rpm output gives 3.00:1. If the controller expects 2.50:1, investigate slip, speed sensing or incorrect gear application.

Measurement and verification sequence

  • Verify fluid level and temperature using the correct procedure.
  • Log input/turbine/output speeds together.
  • Compare commanded gear/clutch/pressure with achieved ratio/slip.
  • Correlate solenoid electrical current with hydraulic pressure and mechanical response.

Fault-separation logic

  • Is a valid command present and are power/ground/network healthy?
  • Does feedback follow the command?
  • Does an independent physical measurement confirm the output?
  • Is the fault limited to a specific temperature/load/speed condition?
  • Does the result remain stable when the original condition is repeated after repair?

Technical sources

  1. UNECE Vehicle Regulations / WP.29
  2. European Union vehicle type-approval framework
  3. Otodünyam teknik editoryal sınıflandırması
  4. Bosch Mobility technical knowledge

Continue investigating

Model-specific real technical data · Measurement references · Technical diagnostic atlas