How to Perform a Throttle Relearn on Daewoo Vehicles
In this blog post, we discuss the process of performing a throttle relearn on Daewoo vehicles. This procedure is necessary after battery replacement, battery disconnection, or cleaning the electronic throttle body. We explain why a throttle relearn is necessary and how it affects engine performance. We also provide a step-by-step guide on how to perform the throttle relearn procedure at home, with no special tools required.<>
Additionally, we discuss the Daewoo models that require a throttle relearn and provide troubleshooting tips for common issues that may arise during the relearn process. Overall, this blog post aims to help Daewoo vehicle owners understand the importance of a throttle relearn and guide them through the process.<>
If you own a Daewoo vehicle and have recently replaced the battery, disconnected the battery, or cleaned the electronic throttle body, you may need to perform a throttle relearn procedure. A throttle relearn, also known as an idle relearn, allows the vehicle’s engine control module (ECM) to relearn the correct position of the throttle valve at idle and ensure proper engine operation.<>
Performing a throttle relearn on a Daewoo is a straightforward process that can be done at home with no special tools in most cases. This procedure applies to many Daewoo models, including the Lanos, Nubira, Leganza, and Matiz produced from the late 1990s through the mid-2000s.<>
Why is a Throttle Relearn Necessary?
The electronic throttle body contains a throttle position sensor (TPS) that monitors the opening angle of the throttle valve. The TPS sends a voltage signal to the ECM indicating the current throttle position. The ECM uses this information, along with inputs from other sensors, to calculate the appropriate air-fuel mixture and ignition timing for optimal engine performance, fuel economy, and emissions.<>
Over time, carbon deposits can build up on the throttle valve and affect its ability to close completely. This can cause an incorrect TPS voltage at idle, leading to rough idling, stalling, or high idle speeds. Disconnecting the battery or replacing the throttle body will also clear the learned idle position stored in the ECM’s memory.<>
By performing a throttle relearn, you are teaching the ECM the correct closed-throttle position so it can accurately control the engine at idle. Skipping this step after battery or throttle service can result in poor idle quality and drivability issues.<>
Daewoo Models That Require a Throttle Relearn
Most Daewoo passenger vehicles from the late 1990s and early 2000s have an electronic throttle body that may require a relearn procedure after battery or throttle service. This includes the following models:<>
- Lanos (1997-2002)
- Nubira (1997-2003)
- Leganza (1997-2002)
- Matiz (1998-2005)
Some newer Daewoo and Chevrolet models produced by GM Daewoo after 2002 may have different throttle relearn procedures. Consult your owner’s manual or a factory service manual for model-specific instructions.<>
Before Beginning the Throttle Relearn
Prior to starting the relearn procedure, ensure the following:<>
- The throttle body is clean and free of carbon deposits. If you suspect a dirty throttle body, remove it and clean the throttle valve and bore with throttle body cleaner. Reinstall the throttle body and reconnect any electrical connectors.
- The battery is fully charged and in good condition. Check the battery voltage with a multimeter. It should be at least 12.6 volts with the engine off. Charge or replace the battery if necessary.
- All electrical accessories are turned off, including the headlights, radio, heater fan, rear defrost, etc. Electrical loads during the relearn can affect the results.
- The transmission is in Park (automatic) or Neutral (manual) with the parking brake engaged.
- The check engine light is off. If you have any pending diagnostic trouble codes, resolve them before attempting a throttle relearn. Erase any codes if necessary.
Once you have completed these preliminary checks, you are ready to begin the throttle relearn procedure. The following steps work for most Daewoo models listed above, but some may have slight variations.<>
Performing the Throttle Relearn Procedure
Follow these steps to complete the throttle relearn:<>
- Turn the ignition key to the “ON” position but do not start the engine. Wait for all warning lights on the instrument panel to turn off.
- Turn the ignition key to the “OFF” position and wait 10 seconds.
- Turn the ignition key to the “ON” position again but do not start the engine. Wait for all warning lights to turn off.
- Press and release the accelerator pedal fully 5 times within 5 seconds.
- Wait 7 seconds, then press the accelerator pedal fully and hold it there for 20 seconds until the check engine light starts flashing.
- Release the accelerator pedal and start the engine within 3 seconds. Let the engine idle.
- Wait for the engine to reach normal operating temperature. The cooling fans should cycle on and off at least once.
- Turn off the engine and wait 20 seconds.
- Restart the engine and let it idle for at least 3 minutes. The idle speed may be higher than normal at first but should gradually decrease to the normal range of 650-750 RPM.
- Take the vehicle for a test drive, making sure to drive at various speeds. Apply smooth, gradual throttle inputs. Avoid hard acceleration or deceleration.
- The relearn process is complete once the vehicle operates normally at idle and during driving, with no warning lights illuminated.
If the engine continues to idle roughly or warning lights remain on after performing the relearn, there may be other underlying issues with the throttle body, idle air control system, or fuel injection. Consult a qualified Daewoo mechanic for further diagnosis and repair.<>
Troubleshooting Common Throttle Relearn Issues
Even if you follow the throttle relearn steps correctly, you may encounter some difficulties getting the procedure to complete successfully. Here are some common problems and potential solutions:<>
Engine Won’t Stay Running During Relearn
If the engine stalls or won’t stay running during the relearn, the throttle body may be excessively dirty or sticking. Remove the throttle body and clean it thoroughly with throttle body cleaner. Inspect the throttle plate and shaft for binding or damage. Replace the throttle body if necessary.<>
Another possibility is low fuel pressure due to a weak fuel pump or clogged fuel filter. Check fuel pressure with a fuel pressure gauge. Daewoo models should have between 45-55 psi of fuel pressure with the engine running. Replace the fuel filter and/or fuel pump as needed.<>
Idle Stays High After Relearn
If the idle remains high (over 1000 RPM) after completing the relearn procedure, there may be a problem with the idle air control (IAC) valve. The IAC valve is responsible for fine-tuning the idle speed by allowing a measured amount of air to bypass the throttle plate.<>
Over time, the IAC valve can become clogged with carbon deposits, preventing it from regulating idle speed effectively. Remove the IAC valve and clean it with throttle body cleaner. Make sure the valve plunger moves freely and is not seized. Replace the IAC valve if cleaning does not improve operation.<>
Check Engine Light Comes On During or After Relearn
If the check engine light illuminates during the relearn procedure or shortly afterward, there may be a problem with the throttle position sensor (TPS) or its wiring. The TPS is responsible for telling the ECM the current position of the throttle valve.<>
Retrieve any diagnostic trouble codes with an OBD-II scanner. Common TPS-related codes include P0121 (TPS circuit range/performance), P0122 (TPS circuit low voltage), and P0123 (TPS circuit high voltage).<>
Check the TPS wiring connector for damaged or corroded pins. Test the TPS itself with a multimeter. With the ignition on, you should see a smooth increase in voltage as you move the throttle from closed to wide open. If you see a sudden jump or drop in voltage, or no voltage change at all, replace the TPS.<>
Final Words from Boss Erwin
Performing a throttle relearn on your Daewoo vehicle is an important step to take after disconnecting the battery or cleaning the throttle body. The relearn process allows the ECM to determine the correct closed throttle position and idle air flow for optimal engine performance.<>
While the throttle relearn procedure is straightforward for most Daewoo models, issues like a sticking throttle plate, weak fuel pressure, a dirty IAC valve, or a faulty TPS can prevent the relearn from completing successfully. Cleaning the throttle components and checking for trouble codes can help pinpoint the problem.<>