VW Golf’s MIL ON, Engine Speed Limited to 4500 RPM
Oct. 04 2022
Oct. 04 2022

Vehicle: 2017 Volkswagen Golf R 4Motion (5G1), L4-2.0L Turbo (CYFB), Automatic Transmission/Transaxle

Mileage: 92,558

Problem: The owner dropped her VW Golf off at the shop because the malfunction indicator light (MIL) was ON, and the engine would not accelerate past 4500 RPM.

Case Details: The tech hooked up a scan tool and retrieved the following six diagnostic trouble codes (DTCs):

  • P2185 - Engine Coolant Temperature Sensor 2 Circuit
  • P2181 - Cooling System Performance
  • P00B7 - Engine Coolant Low Flow Performance
  • P2681 - Engine Coolant Bypass Valve Circuit Open
  • U1123 - Data Bus Value Error Received
  • P16C7 - Heater Support Pump Blocked

An ALLDATA Tech-Assist consultant advised inspecting the engine temperature control actuator -N493- resistance between connector pins 4 and 5. The factory specifications were 2.4 to 4.6 Ohms. If the test results were out of specifications, he advised replacing the actuator and retesting.

VW Engine Temp Control Actuator

Editor’s NOTE:  For those unfamiliar with VW’s engine temperature control actuator -N493-, here’s how it works. Coolant flow is regulated by means of two mechanically coupled rotary slide valves. The angular position of the rotary slide valves is regulated according to various engine maps stored in the engine control unit. Various switching positions can be implemented by configuring the rotary slide valves accordingly. This allows rapid heating of the engine, in turn, results in lower friction and higher fuel economy.

The technician performed the tests outlined by the T-A consultant and found the internal resistance to be Zero Ohms.

Confirmed Repair: He replaced the engine temperature control actuator -N493- with a new thermostat housing. After clearing the DTCs and adaptives, he gave it an extensive road test. No further issues. Problem solved!

The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips 

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