OBD Guide

P071B

Transmission Mode Switch A Circuit Low

P071B is an OBD-II diagnostic trouble code meaning: Transmission Mode Switch A Circuit Low. Common causes: faulty automatic transmission mode switch, open or short circuit in switch circuit. Estimated repair cost: $17–89.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$17–89 (est.)

Symptoms

  • The car goes into automatic transmission emergency mode
  • Unable to change gears
  • There is no indication of the selected mode on the dashboard
  • Automatic transmission fault indicator flashes
  • The vehicle may not start in 'P' or 'N' position

Causes

  • Faulty automatic transmission mode switch
  • Open or short circuit in switch circuit
  • Poor contact connection or corrosion
  • Problems with the relay or circuit fuse
  • Transmission ECU malfunction

How to Fix

  1. Check the condition of fuses and relays
  2. Inspect switch connections and wiring
  3. Check the resistance of the mode switch
  4. Scan the voltage in the switch circuit
  5. If necessary, replace the automatic transmission mode switch

Related codes

Error P071B by Vehicle Brand

FAQ

What does the P071B code mean?

P071B is an OBD-II diagnostic trouble code that indicates: Transmission Mode Switch A Circuit Low

What causes a P071B error code?

The most common causes of P071B include: Faulty automatic transmission mode switch; Open or short circuit in switch circuit; Poor contact connection or corrosion; Problems with the relay or circuit fuse.

How do I fix a P071B diagnostic trouble code?

To fix P071B: Check the condition of fuses and relays. Inspect switch connections and wiring. Check the resistance of the mode switch. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with P071B?

Do not drive — repair immediately

How much does it cost to fix P071B?

The estimated repair cost for P071B is $17–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat