Rick's Free Auto Repair Advice

Toyota P2118: Causes and Solutions

A Toyota P2118 code is related to the throttle body but the cause is most often a blown fuse

Shops are reporting a high incidence of a Toyota P2118 code. The code is defined as: Throttle Actuator Control Motor Current Range / Performance. This code indicates that there is an issue with your throttle actuator control system. Specifically, it means that the ECU (engine control unit) has detected that the actual throttle position does not match the expected throttle position. The throttle actuator is responsible for controlling the opening of the throttle valve (which regulates airflow into the engine). It does this based on signals it receives from the accelerator pedal position sensor. When these components are out of sync, it triggers the P2118 code.

The most common cause of this code is a blown ETCS fuse 10A in the underhood fuse box on the left side of the engine.  Start by checking the ECTS fuse. If it is blown, replace it. You’ll have to perform a throttle body relearn after you replace the fuse.

What causes a Toyota P2118 trouble code

#1 Dead battery
#2 Cross polarity when jumping
#3 Failure to perform a throttle body relearn after disconnecting the battery

The Toyota Electronic Throttle Control System (ECTS) is an electronic throttle body that remains slightly open when the engine is off. When checking the condition of the ECTS with the engine off, you should see the throttle plate cracked open 5.5°. This is Toyota’s fail-safe mode.

During a fail-safe mode where the throttle body fails, the ECM stops feeding power to the ECTS and allows you to drive by controlling the fuel injector and spark timing to respond to your accelerator pedal inputs. This allows you to drive with a failed ECTS, although at minimal speed.

If you have a dead battery or have replaced the battery, you must perform an idle relearn. If you fail to do this, the throttle body may not operate properly.

Toyota Throttle Body Idle Relearn Procedure

Turn the ignition switch off and wait for at least 30 seconds.
Start the engine and warm it up until the engine coolant temperature is 80°C (176°F) or higher.
After the engine is warmed up, allow it to idle for 5 minutes with the air conditioning and all accessories off.
Confirm that the idle speed is within the standard range.

Other Toyota P2118 trouble code tests

Refer to the Toyota throttle body wiring diagram below. Confirm battery voltage at the throttle body connector M2. Confirm ground on throttle body connector M1. If you have both, disconnect the connector at the throttle body and check for resistance across M1 and M2. At room temperature, you should see 0.3-100Ω. If not, you may have a bad throttle body.

Toyota electronic throttle body wiring diagram

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Posted on by Rick Muscoplat



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