P1700 Code: Transmission Control Module MIL Request – Causes, Symptoms & Fixes with ICARZONE UR1000

P1700 Code: Transmission Control Module MIL Request – Causes, Symptoms & Fixes with ICARZONE UR1000

P1700 Code: Transmission Control Module MIL Request Explained & Fixes

The P1700 code indicates a Transmission Control Module (TCM) request for the Malfunction Indicator Lamp (MIL). It means the TCM has detected a fault and is signaling the Engine Control Module (ECM) to illuminate the Check Engine Light. This code is common in Nissan, Infiniti, and Ford vehicles equipped with automatic transmissions.

1. What Does the P1700 Code Mean?

P1700 does not point to one single fault—it acts as a communication request. The TCM stores a more specific transmission-related fault code, and P1700 simply tells the ECM to alert the driver. To identify the root cause, you’ll need a diagnostic scan tool that can access both ECM and TCM.

2. Common Causes of P1700

  • Transmission Control Module (TCM) internal fault
  • Wiring/connector issues between TCM and ECM
  • Low or contaminated transmission fluid
  • Faulty transmission solenoids
  • Shift timing errors or mechanical transmission wear

3. Symptoms of P1700

  • Check Engine Light or Transmission Warning Light ON
  • Harsh or delayed gear shifts
  • Transmission stuck in “limp mode”
  • Reduced fuel efficiency
  • Erratic RPM during acceleration

4. Diagnosing P1700 with ICARZONE UR1000

The ICARZONE UR1000 is a professional diagnostic tool that can read both ECM and TCM fault codes, making it ideal for diagnosing P1700. Here’s how to use it:

  1. Connect UR1000 to the OBD-II port and power on.
  2. Select the vehicle make and model.
  3. Scan both ECM and TCM for stored fault codes.
  4. Check live data such as transmission temperature, solenoid status, and shift timing.
  5. Record freeze-frame data to understand conditions when the fault occurred.

5. How to Fix P1700

  • Check transmission fluid: Top up or replace if dirty/low.
  • Inspect wiring & connectors: Look for corrosion or loose pins.
  • Test transmission solenoids: Replace if faulty.
  • Reprogram or replace TCM if diagnosed as defective.
  • Clear codes and road-test with UR1000 to confirm the issue is resolved.

6. Preventive Maintenance

  • Regularly service transmission fluid and filter (every 30,000–50,000 miles).
  • Avoid aggressive driving that stresses the transmission.
  • Keep battery and charging system healthy (low voltage can affect TCM).
  • Perform periodic diagnostic scans to catch issues early.

7. FAQs About P1700

Q: Is it safe to drive with code P1700?
A: Driving short distances may be possible, but long-term driving in limp mode or with shifting issues can damage the transmission.

Q: Does P1700 always mean the transmission is failing?
A: Not necessarily. It may be caused by wiring issues or a faulty sensor, but further diagnosis is required.

Q: Can I fix P1700 without a scan tool?
A: No. Since P1700 is a request code, you need a diagnostic scanner like the UR1000 to read the specific TCM fault codes.

8. Summary

P1700 is a request code indicating the TCM has detected a fault and asked the ECM to turn on the Check Engine Light. To identify and fix the issue, you need to scan the TCM with a capable tool such as the ICARZONE UR1000. Ignoring this code may lead to severe transmission damage, so timely diagnosis and repair are crucial.