Reading and Clearing Diagnostic Trouble Codes
How to Troubleshoot the A/T System
How to Check for DTCs with the Honda Diagnostic System (HDS)
When the powertrain control module (PCM) senses an abnormality in the input or output system, the D indicator (A) in the gauge control module (B) will usually blink.
When the Honda Diagnostic System (HDS) is connected to the data link connector (DLC) (A) (located under the driver's dashboard lower cover), it will indicate the diagnostic trouble code (DTC) when the ignition switch is turned to ON (II) and the appropriate menu is selected.
If the D indicator or malfunction indicator lamp (MIL) has been reported on, or if a driveability problem is suspected, follow this procedure:
1. Connect the HDS to the DLC.
2. Turn the ignition switch to ON (II). Make sure the HDS communicates with the PCM. If it does not, go to the DLC circuit troubleshooting Testing and Inspection.
3. Check for Pending or Confirmed DTCs with the HDS.
4. Record the freeze data and the on-board snapshots for all fuel and emissions DTCs, and A/T DTCs.
5. If there is a fuel and emissions DTC, first check the fuel and emissions system as indicated by the DTC (except for DTC P0700, which means there is one or more A/T DTCs, and no problem were detected in the fuel and emissions circuit of the PCM).
6. Clear the DTC and data.
7. Drive the vehicle for several minutes under the same conditions as those indicated by the freeze data, and then recheck for a DTC. If the A/T DTC returns, go to the indicated DTC's troubleshooting. If the DTC does not return, there was an intermittent problem within the circuit. Make sure all pins and terminals in the circuit are tight.
Symptom Troubleshooting Versus DTC Troubleshooting
Some symptoms will not set DTCs or cause the D indicator to blink. If the MIL was reported ON or the D indicator has been blinking, check for DTCs. If the vehicle has an abnormal symptom, and there are no DTCs stored, do the symptom troubleshooting. Check the list of probable cause(s) for the symptom until you find the problem.
How to Check for DTCs with the SCS Mode (retrieving the flash codes)
NOTE: The preferred method is to use the HDS to retrieve the DTCs.
When the PCM senses an abnormality in the input or output system, the D indicator (A) in the gauge control module (B) will usually blink.
When the D indicator has been reported on, connect the HDS to the DLC (A) (located behind the driver's dashboard lower cover). Turn the ignition switch to ON (II), select SCS mode, then the D indicator will indicate (blink) the DTC.
If the D indicator and the MIL come on at the same time, or if a driveability problem is suspected, follow this procedure:
1. Connect the HDS to the DLC.
2. Turn the ignition switch to ON (II). Make sure the HDS communicates with the PCM. If it does not, go to the DLC circuit troubleshooting Testing and Inspection.
3. Select SCS mode, then observe the D indicator in the gauge control module. Codes 1 through 9 are indicated by individual short blinks. Code 10 and above are indicated by a series of long and short blinks. One long blink equals 10 short blinks. Add the long and short blinks together to determine the code.
4. Record all fuel and emissions DTCs and A/T DTCs.
5. If there is a fuel and emissions DTC, first check the fuel and emissions system as indicated by the DTC (except for DTC 70, which means there is one or more A/T DTCs, and no problems were detected in the fuel and emissions circuit of the PCM).
6. Clear the DTC and the data.
7. Drive the vehicle for several minutes under the same conditions as those indicated by the freeze data, and then recheck for DTCs. If the A/T DTC returns, go to the indicated DTC's troubleshooting. If the DTC does not return, there was an intermittent problem within the circuit. Make sure all pins and terminals in the circuit are tight.
Troubleshooting the Circuits at the PCM
Refer to the how to troubleshoot circuits at the PCM connectors Initial Inspection and Diagnostic Overview before getting started with the A/T DTC troubleshooting at the PCM connectors.
How to Clear A/T DTCs
1. Connect the HDS to the DLC (A).
2. Turn the ignition switch to ON (II).
3. Make sure the HDS communicates with the PCM. If it does not, go to the DLC circuit troubleshooting Testing and Inspection.
4. Clear the DTC(s) with the HDS.
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 has successfully completed.
- FAILED: The on-board diagnosis has finished but failed.
- NOT COMPLETED: The on-board diagnosis was running but is out of the enable conditions of the DTC.
PCM/TCM Reset
NOTE: To reset the PCM/TCM, initialize only the automatic transmission memory stored in the PCM or the TCM.
1. Select the A/T system with the HDS.
2. Reset the PCM/TCM with the HDS while the engine is stopped.
3. Turn the ignition switch to LOCK (0).
4. Turn the ignition switch to ON (II), and wait for 30 seconds.
5. Turn the ignition switch to LOCK (0), and disconnect the HDS from the DLC.
Replacing the PCM
Refer to the PCM replacement Service and Repair when replacing the PCM is needed in the DTC troubleshooting.
Updating the A/T Software in the PCM
Refer to the PCM update ECM/PCM Update when the A/T software updating is needed in the DTC troubleshooting.
Substituting the PCM
Refer to the substituting the ECM/PCM Initial Inspection and Diagnostic Overview when substituting a known-good PCM is needed in the DTC troubleshooting.
How to End a Troubleshooting Session (required after any troubleshooting)
NOTE: Reset the PCM/TCM with the HDS while the engine is stopped.
1. Do the PCM idle learn procedure ECM/PCM Idle Learn Procedure.
2. Turn the ignition switch to LOCK (0).
3. Turn the ignition switch to ON (II), and wait for 30 seconds.
4. Turn the ignition switch to LOCK (0), and disconnect the HDS from the DLC.
5. Start the engine in P or N, and warm it to normal operating temperature (the radiator fan comes on).
6. To verify that the problem is repaired, test-drive the vehicle for several minutes at speeds over 30 mph (50 km/h) or under the same conditions as those indicated by the freeze data.