Diagnostics Guide

Common JF015E Fault Codes & What They Mean

Complete diagnostic reference for understanding and resolving the most common trouble codes in JF015E CVT transmissions.

8 min read
Intermediate Level
Technical Reference
Male technician clicking on screen of diagnostic tool, attached to steering wheel of a car

Understanding Diagnostic Trouble Codes

The JF015E CVT transmission communicates issues through Diagnostic Trouble Codes (DTCs). Understanding these codes is the first step toward accurate diagnosis and effective repair. This guide covers the most commonly encountered fault codes in JF015E transmissions.

P0731 - Gear Ratio Error

Critical Issue

What It Means

The TCM has detected an incorrect gear ratio. The actual ratio doesn't match the expected ratio for the current driving conditions. This indicates mechanical wear or hydraulic pressure problems.

Common Causes

  • Worn CVT belt causing slippage
  • Damaged pulley surfaces reducing grip
  • Low hydraulic pressure from pump wear
  • Contaminated CVT fluid reducing friction

Recommended Solutions

  1. Check CVT fluid level and condition - replace if contaminated
  2. Perform hydraulic pressure test to verify pump operation
  3. Inspect belt and pulley surfaces for wear or glazing
  4. If belt/pulleys worn, complete replacement is recommended

P17F0 - Primary Pressure Sensor Circuit

Electrical Issue

What It Means

The primary pressure sensor is reading out of range or not communicating properly with the TCM. This sensor monitors hydraulic pressure in the primary pulley circuit.

Common Causes

  • Failed primary pressure sensor
  • Damaged wiring harness or connectors
  • Corrosion at sensor connector pins
  • TCM power supply issues

Recommended Solutions

  1. Check sensor connector for corrosion or damage
  2. Test sensor resistance and voltage output
  3. Inspect wiring harness for breaks or shorts
  4. Replace sensor if readings are out of specification

P0842 - Secondary Pressure Sensor Circuit

Pressure Monitoring

What It Means

The secondary pressure sensor is reporting abnormal readings or has lost communication. This sensor monitors hydraulic pressure at the secondary (driven) pulley.

Common Causes

  • Sensor failure due to heat exposure
  • Electrical connector contamination
  • Short circuit in wiring harness
  • Actual hydraulic pressure problems

Recommended Solutions

  1. Verify actual hydraulic pressure with mechanical gauge
  2. Test sensor electrical values against specifications
  3. Clean connector and check for proper seating
  4. Replace sensor if electrical test fails

P0705 - Transmission Range Sensor Circuit

Selector Issue

What It Means

The gear selector position sensor (inhibitor switch) is not sending valid signals to the TCM. The transmission doesn't know which gear position has been selected.

Common Causes

  • Failed inhibitor switch/position sensor
  • Misadjusted sensor position
  • Broken wiring at transmission case
  • Worn selector linkage causing misalignment

Recommended Solutions

  1. Check selector linkage adjustment and wear
  2. Test sensor resistance in each gear position
  3. Adjust or replace position sensor as needed
  4. Verify proper mechanical linkage operation

Professional Diagnostic Tips

Always Start With Basics

Before diving into complex diagnostics, verify fluid level, check for obvious leaks, and ensure battery voltage is adequate. Many codes are triggered by simple issues.

Document Everything

Record all fault codes, freeze frame data, and test results. Multiple codes often point to a common root cause. Pattern recognition is key to efficient diagnosis.

Use Genuine Scan Tools

Generic OBD scanners may miss JF015E-specific codes. Use Nissan Consult III or equivalent professional equipment for complete diagnostics and live data monitoring.

Test Drive Verification

After repairs, perform a thorough test drive mimicking the conditions that triggered the code. Clear codes only after confirming the issue is resolved.

Need Professional Diagnostic Help?

Our technical team can provide remote diagnostic support or handle the complete repair for you.