Code Severity and Symptoms
The severity of this code can range from moderate to severe depending on the specific malfunction. Symptoms of a P2108 fault code may include:
- Engine does not start
- Worsening poor performance
- Little or no throttle response
- Check engine light illuminated
- Exhaust smoke
- Increased fuel consumption
Common Causes of P2108 Code
Possible causes of this code may include:
- Faulty throttle body
- Dirty throttle plate or linkage
- Defective throttle position sensor
- Faulty accelerator pedal position sensor
- Defective throttle actuator control motor
- Corroded or damaged connector
- Faulty or damaged wiring
- Faulty PCM
- Common repairs
- Throttle body replacement
- Cleaning throttle plate and linkage
- Throttle position sensor replacement
- Throttle actuator control motor replacement
- Accelerator pedal position sensor replacement
- Cleaning connector corrosion
- Repairing or replacing wiring
- Replacing PCM
Diagnostic and Repair Procedures
Check TSBs
The first step in troubleshooting any malfunction is to search for Technical Service Bulletins (TSBs) for the specific vehicle by year, model, and powertrain. In some circumstances, this can save significant time in the long run by pointing you in the right direction.
The second step is to locate all components associated with the electronic throttle control system. This will include the throttle body, throttle position sensor, throttle actuator control motor, PCM, and accelerator pedal position sensor on a simplex system. Once these components are located, a thorough visual inspection should be performed to check that all associated wiring shows no obvious defects such as scraping, rubbing, bare wires, burning, or melted plastic. Next, check each component’s connectors for security, corrosion, and damaged pins.
The final visual and physical inspection is the throttle plate. With ignition off, you should be able to rotate the throttle plate by pushing on it. It should rotate to wide open position. If there is sludge buildup behind the plate, it should be cleaned while accessible.
Advanced Steps
Advanced steps become very vehicle-specific and require appropriate advanced equipment to perform accurately. These procedures require a digital multimeter and vehicle-specific technical references. Voltage requirements will be highly dependent on the specific vehicle year, model, and engine.
Circuit Checks
With the ignition switch in the off position, disconnect the electrical connector from the throttle body. Locate the 2 pins that go to the motor(s) on the throttle body. Using a digital ohmmeter set to ohms, check the resistance of the motor(s). The motor should read approximately between 2 and 25 ohms depending on the specific vehicle (consult manufacturer specifications for your vehicle). If resistance is too high or too low, the throttle body will need to be replaced. If all tests have passed up to this point, you’ll want to check the motor voltage signals.
If this process identifies missing power source or ground, continuity tests may be required to verify wiring integrity. Continuity tests should always be performed with power disconnected from the circuit and normal readings should be 0 ohms resistance unless otherwise specified in technical data. Resistance or lack of continuity indicates faulty wiring that needs to be repaired or replaced.
I hope the information in this article has helped point you in the right direction to correct the issue with your electronic throttle control system. This article is strictly informational and your vehicle-specific technical data and service bulletins should always take priority.