ECM Reset

HDS Clear Command

The ECM/PCM stores various specific data to correct the system even if there is no electrical power such as when the battery negative terminal or No. 8 FI ECU (ECM/PCM) (15 A) fuse are disconnected. Stored data based on failed parts should be cleared by using the "CLEAR COMMAND" of the HDS, if parts are replaced.

The HDS has three kinds of clear commands to meet this purpose. They are DTC clear, ECM/PCM reset, and CKP pattern clear. DTC clear command erases all stored DTC codes, freeze data, readiness codes, and the on-board snapshot. This must be done with the HDS after reproducing the DTC during troubleshooting.
The ECM/PCM reset command erases all stored DTC codes, freeze data, readiness codes, on-board snapshot, and all specific data to correct the system except CKP pattern. If the CKP pattern data in the ECM/PCM was cleared, you must do the CKP pattern learn procedure. The CKP pattern clear command erases only CKP pattern data. This command is for repair of a misfire or the CKP sensor.

Scan Tool Clear Command

If you are using a generic scan tool to clear commands, be aware that there is only one setting for clearing the ECM/PCM, and it clears all commands at the same time (CKP pattern learn, idle learn, readiness codes, freeze data, on-board snapshot, and DTCs). After you clear all commands, you then need to do these procedures, in this order: ECM/PCM idle learn procedure; CKP pattern learn procedure; Test-drive to set readiness codes to complete.

DTC dear

1. Clear the DTC with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and wait for 30 seconds.
4. Turn the ignition switch OFF, and disconnect the HDS from the DLC.

ECM/PCM Reset

This command clears stored specific data from each vehicle such as DTCs, freeze data, on-board snapshot, and readiness codes. It does not clear CKP pattern data.

1. Reset the ECM/PCM with the HDS while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and wait for 30 seconds.
4. Turn the ignition switch OFF, and disconnect the HDS from the. DLC.
5. Do the ECM/PCM idle learn procedure.

CKP Pattern Clear/CKP Pattern Learn

NOTE: The ECT needs to be at 176 degree F (80 degree C) or higher.

1. Clear the CKP pattern while the engine is stopped.
2. Turn the ignition switch OFF.
3. Turn the ignition switch ON (II), and wait for 30 seconds.
4. Test-drive the vehicle on a level road: decelerate (with the throttle fully closed) from an engine speed of 2,500 rpm to 1,000 rpm with the A/T in 2 position, or M/T in 1st gear.
5. Stop the vehicle, but keep the engine running.
6. Check PULSER F/B LEARN in the DATA LIST with the HDS. If it is NOT COMPLETED, go to step 4. If it is COMPLETED, go to step 7.
7. Test-drive the vehicle on a level road: decelerate (with the throttle fully closed) from an engine speed of 5,000 rpm to 3,000 rpm with the A/T in 2 position, or M/T in 1st gear.
8. Stop the vehicle, but keep the engine running.
9. Check the PULSER F/B LEARN (HIGH RPM) in the DATA LIST with the HDS. If it is NOT COMPLETED, go to step 7. If it is COMPLETED, go to step 10.
10. Turn the ignition switch OFF.
11. Turn the ignition switch ON (II), and wait for 30 seconds. The CKP learning procedure is completed.

How to End a Troubleshooting Session (required after any troubleshooting)

1. Reset the ECM/PCM with the HDS.
2. Do the ECM/PCM idle learn procedure.
3. Turn the ignition switch OFF.
4. Disconnect the HDS from the DLC.

NOTE: The ECM/PCM is part of the immobilizer system. If you replace the ECM/PCM, it will have a different immobilizer code. In order for the engine to start, you must rewrite the immobilizer code with the HDS.