S2000 L4-2.2L (2004)
Engine Control Module: Service and Repair
Control Module Programming and Relearning
Updating the ECM
How to Substitute the ECM for Testing Purposes
Use this procedure if you need a known-good ECM to test a vehicle. It allows you to swap a ECM from a "donor" vehicle without having to program it
to the test vehicle's ignition key.
1. Disconnect the negative cable from the battery on the test vehicle.
2. Cut a temporary ignition key for the test vehicle with a non-immobilizer key blank.
3. Remove the ECM from the test vehicle.
4. Write the test vehicle's VIN on the ECM you just removed to avoid confusing it with the donor vehicle's ECM.
5. Disconnect the negative cable from the battery on the donor vehicle.
6. Remove the known-good ECM from the donor vehicle, and install it in the test vehicle.
7. Tape the donor vehicle's ignition key head-to-head to the test vehicle's temporary key (A). The ECM will recognize the code from the donor
vehicle's key (B) and allow you to start the engine with the temporary key.
8. After completing your tests, reinstall both ECMs, and destroy the temporary key.
9. Reconnect the negative cable to the battery.
Idle Learn Procedure
ECM Idle Learn Procedure
The idle learn procedure must be done so that the ECM can learn the engine idle characteristics. Do the idle learn procedure whenever you do any of
these actions:
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Disconnect the battery.
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Replace the ECM or disconnect its connector.
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Reset the ECM.
NOTE: Erasing DTCs with HDS does requires the idle learn procedure to be done again.
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Remove the No. 6 ECU (ECM) (15 A) fuse from the under-dash fuse/relay box.
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Remove the No. 41 BATTERY (100 A) fuse from the under-hood fuse/relay box.
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Remove the PGM-FI main relay.
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Remove the battery wire from the under-hood fuse/relay box.
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Disconnect any of the connectors from the under-hood fuse/relay box.
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Disconnect the connector (C404) between the dashboard wire harness A and dashboard wire harness B.
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Disconnect the G1 terminal.
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Adjust the idle speed.
To complete the idle learn procedure do this:
1. Make sure all electrical items (A/C, audio, rear window defogger, lights, etc.) are turned off.
2. Start the engine. Hold the engine speed at 3,000 rpm with no load (in neutral) until the radiator fan comes on, or the engine coolant temperature
reaches 176 °F (80 °C) -212 °F (100 °C).
3. Let the engine idle for about 5 minutes with the throttle fully closed and with all electrical items off.
NOTE: If the radiator fan comes on during this step, the time when it is operating must not be included in the 5 minutes.
