OBD-II code · Powertrain (generic)
P071B Transmission Mode Switch A Circuit Low
Same as P071A with the signal shorted to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P071B?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.4–1.5 h
- Emissions test
- Usually unaffected
- Parts involved
- Transmission Mode Switch A
Related codes
- P071ETransmission Mode Switch B Circuit Low
- P07CCTransmission Mode Switch C Circuit Low
- P07CFTransmission Mode Switch D Circuit Low
- P07D2Transmission Mode Switch E Circuit Low
- P07D5Transmission Mode Switch F Circuit Low
- P0718Input or Turbine Shaft Speed Sensor A Circuit Intermittent
- P0719Brake Switch B Circuit Low
- P071ATransmission Mode Switch A Circuit
- P071CTransmission Mode Switch A Circuit High
- P071DTransmission Mode Switch B Circuit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.