Reading and Clearing Diagnostic Trouble Codes
How to Troubleshoot the Fuel and Emissions Systems
Intermittent Failures
The term intermittent failure means a system may have had a failure, but it checks OK now. If the malfunction indicator lamp (MIL) on the dash does not come on, check for poor connections or loose terminals at all connectors related to the circuit that you are troubleshooting. If the MIL was on but then went out, the original problem may have been intermittent.
Service Information
Periodically, new ECM/PCM software or new service procedures may become available. Always check online for the latest software or service information related to the DTCs or symptoms you are troubleshooting.
Opens and Shorts
Open and short are common electrical terms. An open is a break in a wire or at a connection. A short is an accidental connection of a wire to ground or to another wire. In simple electronics, this usually means something won't work at all. With complex electronics (such as ECMs or PCMs) this can sometimes mean something works, but not the way it's supposed to.
How to Use the HDS (Honda Diagnostic System)
If the MIL (malfunction indicator lamp) has come on
1. Start the engine, and check the MIL (A).
NOTE: If the ignition switch is turned to ON (II), and the engine is not started, the MIL stays on for 15-20 seconds Monitors, Trips, Drive Cycles and Readiness Codes.
2. If the MIL stays on, connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
3. Turn the ignition switch to ON (II).
4. Make sure the HDS communicates with the ECM/PCM and other vehicle systems. If it doesn't, go to the DLC circuit troubleshooting Testing and Inspection.
5. Check the diagnostic trouble code (DTC) and note it. Also check the freeze data and/or on-board snapshot data, and download any data found. Then refer to the indicated DTC's troubleshooting, and begin the appropriate troubleshooting procedure.
NOTE:
- Freeze data indicates the engine conditions when the first malfunction, misfire, or fuel trim malfunction that activated the MIL was detected.
- The HDS can read the DTC, the freeze data, the on-board snapshot, the current data, and other engine control module (ECM) or powertrain control module (PCM) data.
- For specific operations, refer to the user's manual that came with the HDS.
6. If no DTCs are found, go to the MIL circuit troubleshooting MIL Circuit Troubleshooting.
If the MIL did not stay on
If the MIL did not stay on but there is a driveability problem, do the symptom troubleshooting.
If you can't duplicate the DTC
Some of the troubleshooting requires you to reset the ECM/PCM and try to duplicate the DTC. If the problem is intermittent and you can't duplicate the code, do not continue through the procedure. To do so will only result in confusion and possibly, a needlessly replaced ECM/PCM.
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 the No. 6 FI ECU (15 A) fuse is 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. The DTC clear command erases all stored DTC codes, freeze data, on-board snapshot, and readiness codes. 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, on-board snapshot, readiness codes, 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 ECM/PCM Idle Learn Procedure; CKP pattern learn procedure; test-drive to set readiness codes to complete Monitors, Trips, Drive Cycles and Readiness Codes.
DTC Clear
1. Clear the DTC with the HDS while the engine is stopped.
2. Turn the ignition switch to LOCK (0).
3. Turn the ignition switch to ON (II), and wait 30 seconds.
4. Turn the ignition switch to LOCK (0), and disconnect the HDS from the DLC.
ECM/PCM Reset
1. Reset the ECM/PCM with the HDS while the engine is stopped.
2. Turn the ignition switch to LOCK (0).
3. Turn the ignition switch to ON (II), and wait 30 seconds.
4. Turn the ignition switch to LOCK (0), and disconnect the HDS from the DLC.
5. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.
CKP Pattern Clear/CKP Pattern Learn
Clear/Learn Procedure (with the HDS)
1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the ECM/PCM and other vehicle systems. If it doesn't, go to the DLC circuit troubleshooting Testing and Inspection.
4. Select CRANK PATTERN in the ADJUSTMENT MENU with the HDS.
5. Select CRANK PATTERN CLEAR, and clear the CKP pattern.
6. Select CRANK PATTERN LEARNING with the HDS, and follow the screen prompts.
Learn Procedure (without the HDS)
1. Start the engine. Hold the engine speed at 3,000 rpm without load (A/T in P or N, M/T in neutral) until the radiator fan comes on.
2. Test-drive the vehicle on a level road: Decelerate (with the throttle fully closed) from an engine speed of 2,500 rpm down to 1,000 rpm with the A/T in 2, or M/T in 2nd.
3. Repeat step 2 several times.
4. Turn the ignition switch to LOCK (0).
5. Turn the ignition switch to ON (II), and wait 30 seconds.
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 ECM/PCM Idle Learn Procedure.
3. Turn the ignition switch to LOCK (0).
4. Disconnect the HDS from the DLC.
NOTE: The ECM/PCM is part of the immobilizer system. If you replace the ECM/PCM, for the engine to start, you must use the HDS to instruct the new ECM/PCM and the immobilizer-keyless control unit to recognize each other's unique serial code.
How to Troubleshoot Circuits at the ECM/PCM Connectors
Special Tools Required
- Digital Multimeter KS-AHM-32-003
- Backprobe Set 07SAZ-001000A (2)
1. Connect the backprobe adapters (A) to the stacking patch cords (B), and connect the cords to a digital multimeter (C).
2. Using the wire insulation as a guide for the contoured tip of the backprobe adapter, gently slide the tip into the connector from the wire side until it touches the end of the wire terminal.
3. If you cannot get to the wire side of the connector or if the wire side is sealed (A), disconnect the connector, and probe the terminals (B) from the terminal side. Do not force the probe into the connector.
NOTICE
Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.
Substituting the ECM/PCM
Special Tools Required
- Honda Diagnostic 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
- MVCI unit with the latest control module (CM) update software installed
Any one of the above updating tools can be used.
NOTE: Use this procedure when you have to substitute a known-good ECM/PCM during troubleshooting procedure.
1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the ECM/PCM and other vehicle systems. If it doesn't, go to the DLC circuit troubleshooting Testing and Inspection. If you are returning from DLC circuit troubleshooting, skip steps 4 and 5, then clean the throttle body after substituting the ECM/PCM Procedures.
4. Select the INSPECTION MENU with the HDS.
5. Select the ETCS TEST, then select the TP POSITION CHECK and follow the screen prompts.
NOTE: If the TP POSITION CHECK indicates FAILED, continue this procedure.
6. Turn the ignition switch to LOCK (0).
7. Jump the SCS line with the HDS.
8. Remove the passenger's dashboard undercover Passenger's Dashboard Undercover Removal/Installation, the passenger's kick panel Service and Repair, and the glove box Service and Repair.
9. Cut the plastic cross brace in the glove box opening with diagonal cutters in the area shown, and discard it.
10. Remove the relays (A), then remove the bolts (B) and the glove box frame (C).
11. Remove the gray 20P ECM/PCM wire harness connector (A) from the ECM/PCM mounting bracket.
12. Disconnect the ECM/PCM connectors (B).
13. Remove the ECM/PCM mounting bolt (C) and the bracket.
14. Remove the nuts (D), then remove the ECM/PCM (E).
15. Install the parts in the reverse order of removal.
16. Open the SCS line with the HDS.
17. Turn the ignition switch to ON (II).
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.
18. Manually input the VIN to the ECM/PCM with the HDS.
19. Select the IMMOBI SYSTEM with the HDS.
20. Enter the immobilizer ECM/PCM code that you got from in, and use the ECM/PCM replacement procedure in the IMMOBI MENU of the HDS; it allows you to start the engine.
21. If the TP POSITION CHECK failed in step 5, clean the throttle body Procedures.
22. Reset the ECM/PCM with the HDS.
23. Update the ECM/PCM if it does not have the latest software ECM/PCM Update.
24. Do the ECM/PCM idle learn procedure ECM/PCM Idle Learn Procedure.
25. Do the CKP pattern clear/CKP pattern learn procedure.
OBD Status
The OBD status shows the current system status of each DTC and all of the parameters. This function is used to see if the repair was successfully completed. The results of diagnostic tests for the DTC are displayed as:
- PASSED: The on board diagnosis is successfully finished.
- FAILED: The on board diagnosis has finished but failed.
- EXECUTING: The vehicle is in enable criteria conditions of the DTC and the on board diagnosis is running.
- NOT COMPLETED: The on board diagnosis was running but is out of the enable conditions of the DTC.
- OUT OF CONDITION: The vehicle has stayed out of the enable conditions of the DTC.