P1706 — Reverse Engagement Error

For Ford vehicles

LMP sensor indicates the shift lever is in p position while the vehicle is moving

powertrain (engine/transmission)

Is it safe to drive?

Short-term driving is OK In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P1706 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the reverse engagement error for damage, corrosion, chafing or poor contact.
Subsystem check Measure reference voltage, ground and signal continuity at the component connector.
Subsystem check Wiggle-test the harness while watching the signal in live data — dropouts reveal broken wires.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P1706 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P1706 (parts and labor, USD, independent shop rates): Control module repair: $300–$1,000; Replace the faulty sensor or actuator: $150–$500; Repair wiring or connectors: $80–$250. Overall, fixing P1706 usually costs between $80 and $1,000. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

How do I diagnose P1706 myself?

Start with a scan: confirm P1706, save the freeze frame and note any companion codes. Then inspect the wiring and connectors related to the sensor and actuator circuits, and verify the suspect component against live data before buying parts.

Is it safe to drive with P1706?

In most cases the car remains drivable, possibly with reduced performance or a disabled auxiliary system. If symptoms include stalling, no-start or brake/steering warnings, treat it as urgent.

How much does it cost to fix P1706?

Control module repair — $300–$1,000; Replace the faulty sensor or actuator — $150–$500; Repair wiring or connectors — $80–$250. Exact cost depends on the root cause, your vehicle and local labor rates — a proper diagnosis is the cheapest first step.

What are the symptoms of P1706?

Drivers most often notice: the affected system operates intermittently or not at all, possible limp mode depending on the affected component, Check Engine Light on, increased fuel consumption in some cases.

What is the most common cause of P1706?

The most common causes are: open or shorted wiring in the circuit, faulty sensor or actuator of the affected circuit, control module driver fault.

When your vehicle's onboard diagnostics detect that a sensor or actuator circuit is not behaving as expected during reverse gear selection, the system logs OBD2 code P1706. This specific trouble code falls into the powertrain category and carries the official description "Reverse Engagement Error." In practical terms, the transmission control system has received or transmitted signals that do not align with what the engine control unit anticipates when you shift into reverse.

The relevant control module constantly evaluates the electrical circuits feeding it information from sensors and operating actuators. It compares incoming data against predetermined acceptable ranges throughout your drive. If those readings fall outside the expected parameters for a sustained period across multiple drive cycles, the ECU records P1706 and activates the check engine light. The freeze frame data stored alongside the code is especially useful—it captures the precise engine conditions (RPM, load, temperature, vehicle speed) the moment the fault was detected, giving you an exact reference point for diagnosis.

Common Symptoms of P1706

The system associated with reverse engagement operates intermittently or stops functioning entirely
The vehicle may enter limp mode depending on which component is affected
Check Engine Light remains illuminated on the dashboard
Some drivers report increased fuel consumption as a secondary effect
Reverse gear engagement may feel delayed, rough, or fail entirely
In rare cases, unrelated auxiliary systems may behave unexpectedly due to shared circuit architecture

What Triggers P1706?

The root causes most frequently encountered with P1706 center on electrical integrity:

Wiring harness damage — open circuits, shorts, or damaged insulation in the affected wiring
Faulty sensor or actuator — the specific component sending incorrect data or failing to respond
Control module driver fault — the ECU's internal circuitry managing that circuit has failed
Blown fuse — a failed fuse interrupting power to the affected circuit
Connector problems — corroded, bent, or loose terminals preventing reliable electrical contact

Diagnosing P1706

A methodical approach prevents unnecessary part replacements:

Connect an OBD2 scanner and verify P1706 is currently stored. Save the freeze frame data immediately—this snapshot of engine conditions when the fault occurred is your roadmap for recreating the problem.
Scan for any additional trouble codes. Related codes often expose the actual failing component rather than the downstream effect. Check manufacturer technical service bulletins for your specific make and model using your VIN on the manufacturer's site or nhtsa.gov—many P0xxx codes have documented factory fixes or software updates.
Perform a hands-on visual inspection of the wiring harness and connectors tied to the reverse engagement circuit. Look for chafed insulation, melted wiring, corrosion buildup, or connectors that are not fully seated.
With the connector disconnected, measure reference voltage, ground integrity, and signal continuity at the component harness using a multimeter. Compare readings against manufacturer specifications.
Conduct a wiggle test on the harness while monitoring live data on your scanner. Any signal dropouts or interruptions point to broken wires hidden inside the insulation.
After addressing any found issues, clear the code and complete a full drive cycle—including the specific conditions recorded in your freeze frame data—to confirm P1706 does not return.

Repair Options for P1706

Address the least expensive and most common issues before considering component replacement:

Wiring repair or connector replacement: $80–$250
Sensor or actuator replacement: $150–$500
Control module repair or replacement: $300–$1,000

Total Repair Cost for P1706

Your final invoice depends entirely on which part caused the fault. Based on typical independent shop rates in the United States, expect to pay somewhere between $80 and $1,000 for parts and labor combined. The full diagnosis is worth the investment upfront—the most expensive repair scenario is rarely where you should start, and identifying the actual failing component before purchasing parts keeps your total cost at the lower end of the range.

Can You Drive with P1706?

In most situations, your vehicle remains driveable with P1706 stored, though you may notice reduced performance or a disabled auxiliary function. If the underlying fault causes stalling, failure to start, or triggers warnings related to braking or steering, treat the situation as urgent and seek repair promptly.