01 Mechanics Say This Common Driving Behavior Causes More Engi… • 02 Car Rattling and Shaking while Idling: Causes and Fixes • 03 This Is Why Your Car’s Headlights Are Dim • 04 This is Why Ignoring Your Oxygen Sensor Could Cost You Thou… • 05 This Maintenance Myth Is Turning Small Car Issues Into Huge… • 06 The Hidden Dangers of LPG Conversion for Vehicles • 07 WHAT IS AN ABS SENSOR? • 08 The Gearbox Technology That Makes Every Driver's Car Unique… • 09 Avoid These Brake Pads If You Drive in Rainy or Coastal Reg… • 10 Mechanics Explain Shocking Reason Cars Overheat More Often … •

DTC codes / Nissan codes / P1607

P1607 · NissanECM Internal Circuit Failure A

P1607 on Nissan vehicles indicates that the Engine Control Module (ECM) has detected an internal circuit fault within its own processing or memory hardware. The ECM continuously self-tests critical internal components, and when a failure is logged in the backup memory or a processing error occurs, it sets this code and illuminates the Check Engine Light.

SystemPowertrain
Code typeNissan specific
SeverityHigh
Fix difficultyProfessional
AreaComputer and output circuits

Symptoms you may notice

  • Check Engine Light illuminated, often with no other symptoms
  • Engine may enter limp mode or have reduced power
  • Intermittent stalling or rough running
  • Difficulty starting or no-start condition
  • Poor fuel economy or erratic transmission shifting
  • Other unrelated trouble codes may be stored simultaneously

Common causes, most likely first

  1. Internal failure of the Engine Control Module (ECM) itself
  2. Poor electrical connection at the ECM harness connectors (corrosion, loose pins)
  3. Damaged or chafed wiring in the ECM power or ground circuits
  4. Voltage supply issues such as a weak battery or faulty alternator
  5. Ground strap corrosion or loose engine-to-chassis ground
  6. Aftermarket electronic accessories interfering with ECM power

How to diagnose and fix it

  1. Verify battery voltage and charging system output; a weak battery can trigger false ECM codes
  2. Inspect and clean ECM harness connectors and grounds for corrosion or looseness
  3. Check for any aftermarket wiring or accessories tapped into ECM circuits
  4. Perform a voltage drop test on ECM power and ground circuits
  5. Clear the code and test-drive to see if it returns immediately
  6. If the code persists after electrical checks, replace and reprogram the ECM
  7. After replacement, perform idle relearn and verify no other codes are present

When P1607 Is Not a Dead ECM

  • A weak or failing battery is a common cause of false P1607 codes on Nissan vehicles, so always load-test the battery before condemning the ECM.
  • Corroded or loose ECM ground connections can mimic an internal ECM failure, so inspect and clean all ground points before replacement.
  • Aftermarket alarms, remote starters, or stereo equipment tapped into the ECM wiring can introduce voltage spikes that set this code.
  • Some Nissan models store P1607 as a history code after a temporary voltage dip; clearing and rechecking after a drive cycle can save unnecessary ECM replacement.
  • The ECM may set P1607 alongside other codes; address any communication or sensor codes first, as they can be caused by the same power issue.

Can I keep driving with P1607?

If the vehicle is running normally, you can drive cautiously to a repair shop, but avoid long trips or heavy loads. If the engine is in limp mode, stalling, or has reduced power, stop driving and have the vehicle towed to prevent unsafe driving conditions.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Nissan vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage