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Diagnostic Strategies

General Troubleshooting Procedures

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 wires at all connectors related to the circuit that 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. In complex electronics (like ECM's/PCM's) this can sometimes mean something works, but not the way it's supposed to.

How to Use the PGM Tester or a Scan Tool

If the MIL (Malfunction Indicator Lamp) has come on




1. Start the engine and check the MIL.




2. If the MIL stays on, connect the Honda PGM Tester (A) or an OBDII scan tool to the 16P Data Link Connector (B) located under the driver's side of the dashboard.
3. Turn the ignition switch ON (II).
4. Check the Diagnostic Trouble Code (DTC) and note it. Then also check the freeze frame data. Refer to the DTC Troubleshooting Index and begin the appropriate troubleshooting procedure.
Diagnostic Trouble Code Descriptions


NOTE:
- Freeze frame data indicates the engine conditions when the first malfunction, misfire or fuel trim malfunction was detected.
- The scan tool and the Honda PGM tester can read the DTC, freeze frame data, current data, and other Engine Control Module (ECM)/ Powertrain Control Module (PCM) data.
- For specific operations, refer to the user's manual that came with the scan tool or PGM tester.

If the MIL did not come on
If the MIL did not come on but there is a driveablity problem, refer to the Symptom Troubleshooting index.
Symptom Related Diagnostic Procedures

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.

How to Reset the ECM/PCM
You can reset the ECM/PCM in either of two ways:
- Use the OBDII scan tool or Honda PGM tester to clear the ECM's/PCM's memory.
See the OBDII scan tool or Honda PGM Tester user's manuals for specific instructions.




- Turn the ignition switch OFF, and remove the No.13 CLOCK BACKUP fuse (7.5 A) (A) from the passenger's under-dash fuse/relay box (B) for 10 seconds.

How to End a Troubleshooting Session (required after any troubleshooting)
1. Reset the ECM/PCM as described above.
2. Turn the ignition switch OFF.
3. Disconnect the OBDII scan tool or Honda PGM Tester from the Data Link Connector (16P).

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

How to Remove the ECM/PCM for Testing
If the inspection for a trouble code requires voltage or resistance checks at the ECM/PCM connectors, remove the ECM/PCM and test it:
1. Pull back the carpet from the passenger's and driver's side of the center console to expose the ECM/PCM.




2. Remove the two bolts from the ECM/PCM (A).

How to Troubleshoot Circuits at the ECM/PCM

Special Tools Required
- Digital Multimeter or a commercially available digital multi meter KS-AHM-32-003 (1) or a commercially available digital multimeter
- Backprobe Set 07SAZ-001000A (2)
1. Connect the backprobe adapters (A) to the stacking patch cords (B), and connect the cords to a 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 the wire side is sealed (A), disconnect the connector and touch the tester probe (B) to terminals (C) from the terminal side. Do not force the probe into the connector.

NOTE: Do not puncture the insulation on a wire. Punctures can cause poor or intermittent electrical connections.

How to substitute the ECM/PCM for testing purposes
Use this procedure if you need a known-good ECM/ PCM to test a vehicle. It allows you to swap a ECM/PCM from a "donor" vehicle without having to program it to the test vehicle's ignition key.
1. Cut a temporary ignition key for the test vehicle with a non-immobilizer key blank.
2. Remove the ECM/PCM from the test vehicle.
3. Write the test vehicle's VIN on the ECM/PCM you just removed to avoid confusing it with the donor vehicle's ECM/PCM.
4. Remove the known-good ECM/PCM from the donor vehicle, and install it in the test vehicle.




5. Tape the donor vehicle's ignition key head-to-head to the test vehicle's temporary key (A). The ECM/PCM will recognize the code from the donor vehicle's key (B) and allow you to start the engine with the temporary key.
6. After completing your tests, reinstall both ECMs/PCMs, and destroy the temporary key.
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