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 Replacement
Special Tools RequiredΒ
- Honda diagnostics system (HDS) tablet tester
- Honda interface module (HIM) and an iN workstation with the latest HDS software version
- HDS pocket tester
- GNA600 and an iN workstation with the latest HDS software version
Any one of the above updating tools can be used.
- Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
- Turn the ignition switch to ON (II).
- Make sure the HDS communicates with the ECM/PCM and other vehicle systems. If it doesn't, go to the DLC circuit troubleshooting (see
DLC CIRCUIT TROUBLESHOOTINGΒ ). If you are returning from DLC circuit troubleshooting, skip steps 4 through 7,21 through 23, and 26 and 27, then do this after replacing the ECM/PCM:
- Replace the engine oil (see ENGINE OIL REPLACEMENT ) and the engine oil filter (see ENGINE OIL FILTER REPLACEMENT ).
- Clean the throttle body (see THROTTLE BODY CLEANING ).
- Select the PGM-FI system with the HDS.
- Select the INSPECTION MENU with the HDS.
- Select the ETCS TEST, then select the TP POSITION CHECK, and follow the screen prompts.NOTE: If the TP POSITION CHECK indicates FAILED, continue with this procedure.
- Select the REPLACE ECM/PCM MENU, then select READ DATA and follow the screen prompts.
- Turn the ignition switch to LOCK (0).
- Jump the SCS line with the HDS.
- Remove the passenger's dashboard undercover (see GLOVE BOX REMOVAL/INSTALLATION ), the side kick panel (see TRIM REMOVAL/INSTALLATION - DOOR AREAS ), and the glove box (see GLOVE BOX REMOVAL/INSTALLATION ).
- Cut the plastic cross brace in the glove box opening with diagonal cutters in the area shown, and discard it.
- Remove the relays (A), then remove the bolts (B), and the glove box frame (C).
- Remove the gray 20P ECM/PCM wire harness connector (A) from the ECM/PCM mounting bracket.
- Disconnect the ECM/PCM connectors (B).
- Remove the ECM/PCM mounting bolt (C) and the bracket.
- Remove the nuts (D), then remove the ECM/PCM (E)
- Install the parts in the reverse order of removal.
- Open the SCS line with the HDS.
- Turn the ignition switch to ON (II).
- Manually input the VIN to the ECM/PCM with the HDS.NOTE: DTC P0630 VIN Not Programmed or Mismatch may be stored because the VIN has not been programmed into the ECM/PCM; ignore it, and continue this procedure.
- If the READ DATA (engine oil life) failed in step Β 7, go to step Β 24. Otherwise, go to step 22.
- Select the PGM-FI system with the HDS.
- Select the REPLACE ECM/PCM MENU, then select WRITE DATA and follow the screen prompts.NOTE: If the WRITE DATA indicates FAILED, continue with this procedure.
- Select the IMMOBI system with the HDS.
- Enter the immobilizer code that you got from iN, and use the ECM/PCM replacement procedure in the HDS; it allows you to start the engine.
- If the TP POSITION CHECK failed in step Β 6, clean the throttle body (see THROTTLE BODY CLEANING ), then go to step 27.
- If the READ DATA failed in step 7 or the WRITE DATA failed in step 23, replace the engine oil (see ENGINE OIL REPLACEMENT ) and the engine oil filter (see ENGINE OIL FILTER REPLACEMENT ), ), then go to step 28.
- Select the PGM-FI system, and reset the ECM/PCM with the HDS.
- Update the ECM/PCM if it does not have the latest software (see ECM/PCM UPDATEΒ ).
- Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
- Do the CKP pattern clear/CKP pattern learn procedure (see CRANK (CKP) PATTERN CLEAR/CRANK (CKP) PATTERN LEARN ).
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
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