Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
ECM/PCM Idle Learn Procedure
2005 Honda Accord L4-2.4LSECTION ECM/PCM Idle Learn Procedure
ECM/PCM Idle Learn Procedure
The idle learn procedure must be done so the ECM/PCM can learn the engine idle characteristics.
Do the idle learn procedure whenever you do any of these actions..
- The ECM/PCM is replaced.
- The ECM/PCM is reset.
NOTE: Erasing DTCs with the HDS does not require you to do the idle learn procedure.
- The throttle body is replaced or cleaned.
Procedure
1. Make sure all electrical items (A/C, audio, rear window defogger, lights, etc.) are off.
2. Reset the ECM/PCM with the HDS.
3. Turn the ignition switch ON (II), and wait for 2 seconds.
4. Start the engine, and hold it at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, or until the engine coolant temperature reaches 194 °F (90 °C).
5. Let the engine idle for about 5 minutes with the throttle fully closed.
NOTE: If the radiator fan comes on, do not include its running time in the 5 minutes.
The idle learn procedure must be done so the ECM/PCM can learn the engine idle characteristics.
Do the idle learn procedure whenever you do any of these actions..
- The ECM/PCM is replaced.
- The ECM/PCM is reset.
NOTE: Erasing DTCs with the HDS does not require you to do the idle learn procedure.
- The throttle body is replaced or cleaned.
Procedure
1. Make sure all electrical items (A/C, audio, rear window defogger, lights, etc.) are off.
2. Reset the ECM/PCM with the HDS.
3. Turn the ignition switch ON (II), and wait for 2 seconds.
4. Start the engine, and hold it at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, or until the engine coolant temperature reaches 194 °F (90 °C).
5. Let the engine idle for about 5 minutes with the throttle fully closed.
NOTE: If the radiator fan comes on, do not include its running time in the 5 minutes.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.