How to Troubleshoot A/T Systems

How to Check for DTCs with the Honda Diagnostic System/Scan Tool

When the powertrain control module (PCM) senses an abnormality in the input or output systems, the D indicator (A) in the gauge assembly (B) will usually blink.


When the scan tool or Honda diagnostic system (HDS) is connected to the data link connector (DLC) (A) (located under the dash behind the center console), it will indicate the diagnostic trouble code (DTC) when the ignition switch is turned ON (II).

NOTE: The illustration shows the RHD model; LHD is symmetrical.


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 scan tool or HDS to the DLC. (See the scan tool or HDS user's manual for specific instructions.)

2.Turn the ignition switch ON (II), and observe the fuel and emissions DTCs, A/T DTCs, and freeze data on the screen.

3.If there is a fuel and emissions DTC, first check the fuel and emissions system as indicated by the DTC (except for DTC P0700, DTC P0700 means there is one or more A/T DTCs, and no problems were detected in the fuel and emissions circuit of the PCM).

4.Clear the DTC and data.

5.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 DTC troubleshooting index. 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 symptom will not trigger diagnosis trouble codes (DTCs) or cause the D indicator to blink. If the malfunction indicator lamp (MIL) was reported ON or the D indicator has been blinking, check for DTC. If the vehicle has an abnormal symptom, and there are no DTCs stored, go to the Symptom Troubleshooting Index. Check the list of probable cause(s) for the symptom in the sequence listed, until you find the problem.

How to Troubleshoot Circuits at the PCM

1.Remove the glove box stops, then bring the glove box down.

2.Loosen the mounting nut (A) on the lower portion of the PCM (B), and remove the mounting bolt (C) and nut (D).

NOTE: The illustration shows LHD model; RHD is symmetrical.


3.Lift the PCM up to clear the mounting nut on the lower portion of the PCM, then pull out the PCM.

4.Inspect the circuit on the PCM, according to the DTC troubleshooting with a digital multitester (A) and tapered tip probe (B) as shown.


5.If you cannot get to the wire side of the connector or the wire side is sealed, disconnect the connector and use the tester probe to probe the connectors from the terminal side. Do not force the probe into the connector.

How to Clear A/T DTCs with Removing the fuse

1.Write down the radio presets.

2.Turn the ignition switch OFF.

3.Remove the No. 6 ECU fuse (15A) (A) from the under-dash fuse/relay box (B) for more than 10 seconds.


How to Clear A/T DTCs with the HDS

1.Connect the HDS to the DLC (A).

NOTE: The illustration shows the RHD model; LHD is symmetrical.


2.Turn the ignition switch ON (II).

3.Clear the DTC(s) on the HDS screen.

How to End a Troubleshooting Session

This procedure must be done after any troubleshooting.

1.Reset the PCM by removing the No. 6 ECU fuse (15A) from the under-dash fuse/relay box for more than 10 seconds, or clear the DTC(s) with the HDS.

2.Disconnect the scan tool or HDS.

3.Enter the radio code, reset the preset stations, and set the clock.

4.Write the immobilizer code, if necessary.

5.To verify that problem is repaired, test-drive the vehicle for several minutes at speeds over 50 km/h (30 mph) or under the same conditions as in the freeze data.

PCM Updating and Substitution for Testing

Special Tools Required
Honda Interface Module (HIM) (  EQS05A35570)

Use this procedure when you have to substitute a known-good PCM in a troubleshooting procedure. Update the PCM only if the PCM does not already have the latest software loaded.

Do not turn the ignition switch OFF while updating the PCM. If you turn the ignition switch OFF, the PCM can be damaged.

How to Update the PCM

  • To ensure the latest program is installed, update a PCM whenever the PCM is substituted or replaced.
  • You cannot update a PCM with the program it already has. It will only accept a new program.
  • Before you update the PCM, make sure the vehicle's battery is fully charged.
  • To prevent PCM damage, do not operate any electrical system; audio system, brakes, air conditioning, power windows, moonroof, and door locks, during the update.
  • If you need to diagnose the Honda Interface Module (HIM) because the HIM's red (#3) light came on or was flashing during the update, leave the ignition switch in the ON (II) position when you disconnect the HIM from the DLC. This will prevent PCM damage.

1.Turn the ignition switch ON (II). Do not start the engine.

2.Connect the Honda interface module (HIM) to the DLC (A).

NOTE: The illustration shows the RHD model; LHD is symmetrical.


3.Update the PCM according to the procedures described on the HIM label. If the software in the PCM is the latest, replace the PCM.

How to Substitute the PCM

1.Remove the PCM.

2.Install a known-good PCM.

3.Write the immobilizer code with the PCM replacement procedure in the HDS; this will allow you to start the engine.

4.After completing your test, reinstall the original PCM and rewrite the immobilizer code with the PCM replacement procedure.

OBD Status

The OBD Status shows the current system status of each DTC and all of the parameters for KE, KG, and KS models. This function is used to see if the technician's repair was successfully finished. The results of diagnostic tests for the DTC are displayed as:

  • PASS: On Board Diagnosis is successfully finished.
  • FAILED: On Board Diagnosis has finished but failed.
  • NOT COMPLETED: On Board Diagnosis was running but it is out of the Enable conditions of the DTC.