Understand, Diagnose & Clear P1700: Fix Transmission Gear Selector Control Malfunction with iCarsoft CR Eagle

When your vehicle’s check engine light or transmission warning light turns on, and a diagnostic scan pulls up the P1700 code, you’re dealing with a "Transmission Gear Selector Control Malfunction"—a manufacturer-specific fault common in brands like Chrysler, Dodge, Jeep, Mitsubishi, and some Hyundai/Kia models. This code targets the system that links your gear selector (shifter) to the Transmission Control Module (TCM): it ensures the TCM recognizes the gear you’ve chosen (Park, Reverse, Drive, etc.) and adjusts transmission operation accordingly. A P1700 code disrupts this communication, leading to symptoms like "gear mismatch" (e.g., shifter in Drive but TCM thinks it’s in Neutral), no-start conditions (if the TCM doesn’t detect Park/Neutral), or even transmission limp mode.

With the iCarsoft CR Eagle—a diagnostic tool optimized for transmission and gear selector systems—you can pinpoint whether the issue lies in a faulty shifter sensor, damaged wiring, or TCM glitch, then clear the code once repairs are done. Let’s break down how to resolve P1700 step by step.

Understanding P1700: The Gear Selector-Control Module Connection

To grasp why P1700 matters, first understand the gear selector system’s role:

• Gear Selector (Shifter): The physical lever (console-mounted or column-mounted) you use to choose gears. It has internal sensors (e.g., position sensors, range sensors) that track its location.
• Transmission Control Module (TCM): The "brain" of the transmission— it receives signals from the gear selector sensors to confirm the selected gear, then sends commands to transmission actuators (e.g., solenoids) to engage the gear.
• Communication Circuit: Wires or a CAN bus network that carries sensor signals from the selector to the TCM.

P1700 specifically means the TCM detects a fault in this system: it either doesn’t receive a gear selector signal, receives a corrupted signal, or the signal doesn’t match the actual shifter position. While the exact definition varies by manufacturer:

The core issue—broken selector-TCM communication—remains consistent across makes.

Symptoms of P1700

• Illuminated Warning Lights: The check engine light and/or transmission warning light (often a "PRND" icon with a flash) will glow.
• No-Start Condition: Many vehicles require the TCM to confirm "Park" or "Neutral" to start—if P1700 blocks this signal, the engine won’t crank.
• Gear Mismatch: The dashboard gear indicator (e.g., "D" on the cluster) doesn’t match the shifter position (e.g., shifter in Reverse but cluster shows "N").
• Limp Mode Activation: The TCM may limit the transmission to 2nd or 3rd gear to prevent damage if it can’t confirm the selected gear.
• Unresponsive Shifter: The shifter may feel "loose" or won’t move into certain gears, or the transmission won’t engage the selected gear (e.g., shifter in Drive but vehicle stays in Neutral).

Common Causes of P1700

Why iCarsoft CR Eagle Excels at Diagnosing P1700

The iCarsoft CR Eagle stands out for diagnosing gear selector faults like P1700, as it goes beyond basic code reading to test the selector-TCM communication loop. Here’s its key value:

Step-by-Step: Diagnosing and Clearing P1700 with iCarsoft CR Eagle

1. Confirm the Code and Check Basic Shifter Function

   Connect the CR Eagle to your OBD-II port, select your vehicle (use AutoVIN), and navigate to "Transmission" > "Read Fault Codes" to confirm P1700. Note related codes (e.g., P1701, P1780). Test the shifter: Check if the dashboard indicator matches the shifter position, if the vehicle starts only in Park/Neutral, and for unresponsive gears.

2. Test Gear Selector Sensor Signals

   Go to "Transmission" > "Live Data" > "Gear Selector Parameters." Monitor "Selector Sensor Position," "TCM Recognized Gear," and "Sensor Voltage." Move the shifter through all gears: Mismatched positions indicate wiring/TCM issues; erratic voltage points to a faulty sensor.

3. Inspect Shifter Wiring and Connectors

   Use "Component Location" to find the selector sensor (usually under the console). Disconnect the battery, remove the console (follow CR Eagle’s "Service Guide"), and check the sensor connector for corrosion/bent pins. Test wiring continuity with the CR Eagle’s "Continuity Test"—repair frayed/cut wires with heat-shrink tubing.

4. Test Neutral Safety Switch (If Applicable)

   Navigate to "Special Functions" > "Transmission" > "Neutral Safety Switch Test." Activate the switch manually—if no "Park/Neutral" signal reaches the TCM, replace the switch (CR Eagle displays OEM part numbers).

5. Calibrate Shifter or Update TCM Software

   For electronic shifters: Select "Shifter Sensor Calibration" to align the sensor with the TCM. For software glitches: Go to "Software Management" > "TCM Update" to install the latest firmware (requires Wi-Fi).

6. Repair Mechanical Shifter Issues

   Use the CR Eagle’s "Linkage Adjustment" guide to inspect/replace worn cables/bushings. Adjust linkage so the shifter’s physical position matches the sensor reading (recheck live data after adjustment).

7. Clear the Code and Verify Repairs

   After repairs, select "Clear Codes" to erase P1700. Test: Confirm dashboard indicator matches shifter position, vehicle starts only in Park/Neutral, and transmission engages all gears. Test drive and re-scan—no P1700 means success.

How to Prevent P1700 from Occurring

1. Adopt Gentle Shifter Habits

• Avoid forcing the shifter—never slam into gears or yank to bypass stiffness (wears bushings and sensors).
• Shift into Park only after coming to a complete stop to prevent internal locking mechanism damage.

2. Regularly Inspect Gear Selector Components

• Monthly: Check for spilled liquids under the console (corrode connectors) and wipe up immediately; spray connectors with dielectric grease.
• Quarterly: Inspect shifter cables/linkage for cracks, fraying, or worn bushings (replace with OEM parts).

3. Protect Electrical Components

• Place rodent repellent near the console to prevent wiring damage.
• Clear sunroof/floor drains regularly to avoid moisture under the console (causes corrosion).

4. Maintain TCM Health

• Use the CR Eagle’s "Memory Saver" when replacing the battery to avoid TCM firmware corruption.
• Update TCM software annually via the CR Eagle’s "Software Management" to fix signal glitches.

5. Use the CR Eagle for Preventive Scans

• Monthly "Gear Selector Health Check": Monitor live data for minor position mismatches (calibrate early).
• Pre-emissions test scan: Resolve small issues a week before testing to avoid failures.