P2711: Unexpected Mechanical Gear Disengagement OBD-II Trouble Code

A P2711 DTC will be set if the computer detects a mechanical gear disengagement, as result of data being sent from a number of sensors. The transmission problems related to this code can cause by a number of issues, and can result in serious drivability problems.

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What Transmission Do I Have?

How Serious is the Code?

The P2711 diagnostic trouble code will be stored in the ECU memory if the data from the output shaft speed sensor and input shaft speed sensors do not add up. The output shaft speed sensor should indicate an increase in speed until a gear shift occurs. If the values being sent to the ECU do not match the preset perimeters, the computer will assume that the next gear change has essentially been aborted. If you have a P2711 DTC, you can expect to have a number of drivability issues including hard shifts, failed shifts, engine stalling and other performance-related problems.

Symptoms

Symptoms of a P2711 include:

  • Abrupt gear changes
  • Failed shifts
  • Engine stalls
  • Performance problems with vehicle
  • Speedometer not working

Causes

  • Dirty transmission fluid
  • Damaged/shorted wiring
  • Corroded connectors
  • Faulty output shaft speed sensor
  • Faulty input shaft speed sensor
  • Failing friction elements like clutches or bands
  • Damaged gears
  • Damaged driveshaft/universal joints
  • Valve body problems
  • Software issues

How to Diagnose the Code?

When diagnosing a P2711 OBDII diagnostic trouble code, the ECU memory needs to be scanned for the presence of other diagnostic trouble codes that could shed light on the problem. The transmission fluid should also be checked, manufacturer TSB’s related to the issue need to be researched, and all the wiring and connectors on the transmission wiring harness should be inspected for signs of damage or corrosion. The driveshaft parts also need to be checked for signs of wear and unusual play/looseness. If no issues are found at this point, the input shaft speed sensor and output shaft speed sensor need to be tested. If no problems are found with the sensors, then an internal diagnosis will need to be performed on the friction elements, gears, valve body and other transmission parts.

Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.

What Transmission Do I Have?

What Repairs Will Fix P2711?

  • Change transmission fluid
  • Repair damaged/shorted wiring
  • Replace corroded connectors
  • Replace output shaft speed sensor
  • Replace input shaft speed sensor
  • Replace friction elements
  • Replace damaged gears
  • Replace damaged driveshaft/universal joints
  • Repair/replace valve body
  • Update TCM software

Related Codes

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