OBD Guide

P2779

Downshift Switch Circuit Range/Performance

P2779 is an OBD-II diagnostic trouble code meaning: Downshift Switch Circuit Range/Performance. Common causes: downshift switch malfunction, open or short circuit in wiring. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Yes, but get it checked soon
Approx. repair cost
$17–89 (est.)

Symptoms

  • Inability to downshift
  • Incorrect operation of the low gear mode
  • Turning on the emergency mode of the gearbox
  • Check Engine Light or Transmission Malfunction Is On
  • Reduced vehicle dynamics when driving downhill

Causes

  • Downshift switch malfunction
  • Open or short circuit in wiring
  • Contact problems or terminal oxidation
  • Transmission control module (TCM) malfunction
  • Problems with the control unit software

How to Fix

  1. Check the downshift switch for malfunctions
  2. Check the integrity of the wiring and the condition of the contacts
  3. Diagnose the transmission control module (TCM)
  4. If necessary, replace or reprogram the control unit

Related codes

Error P2779 by Vehicle Brand

FAQ

What does the P2779 code mean?

P2779 is an OBD-II diagnostic trouble code that indicates: Downshift Switch Circuit Range/Performance

What causes a P2779 error code?

The most common causes of P2779 include: Downshift switch malfunction; Open or short circuit in wiring; Contact problems or terminal oxidation; Transmission control module (TCM) malfunction.

How do I fix a P2779 diagnostic trouble code?

To fix P2779: Check the downshift switch for malfunctions. Check the integrity of the wiring and the condition of the contacts. Diagnose the transmission control module (TCM). For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P2779?

Yes, but get it checked soon

How much does it cost to fix P2779?

The estimated repair cost for P2779 is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat