P0599 OBD-II: Thermostat Heater Control Circuit High

P0599 Severity

Urgent

Should you fix P0599 yourself?

Identifying an OBD code is just the start of a complete diagnostic routine. Most trouble codes are caused by a sensor reporting a value that is out of range. Just replacing a sensor may not fix underlying issues. Be sure to understand the code, the part or system in your car that the code refers to, and the risks of delaying professional repair.

Proper diagnosis will save you time and money on unnecessary repairs.

Urgent codes indicate immediate action is necessary. These are urgent and significant malfunctions that can cause severe damage to the vehicle or harm the driver and passengers.

Schedule Diagnosis

What causes OBD-II fault code P0599?

Some newer engines utilize thermostats that are electronically controlled by the engine control module (PCM). If the PCM detects an incorrect signal from thermostat, the PCM will set code P0599.

Need a P0599 diagnosis? Trust our experts.

RepairPal Certified shops provide expert diagnostics and repairs with transparent upfront pricing and a minimum 12-month or 12,000-mile warranty on all services.
30 Certified Locations
Shop Image

Tuffy Tire & Auto Service Center - Grandview

4.7
(81)
2.39 mi
1524 W 5th Ave
Columbus, OH
Closed
Opens 8:00 AM Wed
Call
Shop Image

Excite Auto Repair & Towing

4.4
(15)
5.94 mi
3430 Westerville Road
Columbus, OH
Closed
Opens 9:00 AM Wed
Call
Shop Image

All In Auto Service

4.9
(23)
6.56 mi
5200 Fisher Road
Columbus, OH
Closed
Opens 8:00 AM Wed
Call
Shop Image

Tuffy Tire & Auto Service - Grove City

4.4
(520)
6.67 mi
2131 Stringtown Rd
Grove City, OH
Closed
Opens 7:30 AM Wed
Call
See All 30 Locations

OBD II Fault Code

  • OBD II P0599

OBD-II Code Cooling fans may stay on all the time is defined as a Thermostat Heater Control Circuit High

Some newer engines utilize thermostats that are electronically controlled by the engine control module (PCM). If the PCM detects an incorrect signal from thermostat, the PCM will set code P0599.

Cooling fans may stay on all the time Symptoms

  • Cooling fans may stay on all the time

Common Problems That Trigger the P0599 Code

  • Powertrain Control Module (PCM) failure
  • Thermostat failure
  • Wiring issue

Common Repairs Needed for the P0599 Code

RepairPal Car Genius

Ask our experts about P0599.

RepairPal Car Genius™ is a free resource for vehicle owners seeking advice on maintenance, auto repair, shop inquiries, estimates, and finding a trustworthy repair shop in your area.

 Auto Repair Expert Auto Repair Expert

Call us at 877-913-1554

Available 9am – 6pm ET Monday through Friday

Call Our Experts