Limp mode green key flashing

BDELONG86

MEMBER
2001 HONDA CIVIC
1.7L
AUTOMATIC
209,000 MILES

I was driving my car, and all of a sudden it bogged down and I was in limp mode. I also have a green key light flashing. We tried to hook up a code reader, but it wont link to any code reader. I also had a squeaking belt before hand and well as wheel bearing going bad. It will crank and run rough for maybe 3 or 4 minutes, then be just fine in idle.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,874 POSTS

Have you checked to make sure fuel pressure is within the manufacturer's specs?

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Also, does it start right back up after running 3 to 4 minutes or do you have to wait? If it doesn't start right back up, I need you to check for ignition spark when it refuses to restart.

https://www.2carpros.com/articles/how-to-test-an-ignition-system

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Before you start diagnosing the data link connector (DLC) to determine why you can't connect, check the fuse I indicated in the very last pic.

Here is a flow chart for diagnosing the data link connector. You may have lost power or ground to the port. The attached pics correlate with the directions.

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2001 Honda Civic DX Sedan L4-1668cc 1.7L SOHC MFI
DLC Circuit Troubleshooting
Vehicle Powertrain Management Computers and Control Systems Data Link Connector Testing and Inspection Component Tests and General Diagnostics DLC Circuit Troubleshooting
DLC CIRCUIT TROUBLESHOOTING

If the ECM/PCM does not communicate with the OBD II scan tool, Honda PGM Tester, or I/M test equipment, do this troubleshooting procedure.

pic 1
1. Measure voltage between DLC terminal No.16 and body ground.

Is there battery voltage?

YES - Go to step 2.

NO - Repair open in the wire between DLC terminal No.16 and the No.9 BACK UP (7.5A) fuse in the under-hood fuse/relay box.

pic 2

2. Measure voltage between DLC terminals No.4 and No.16.

Is there battery voltage?

YES - Go to step 3.

NO - Repair open in the wire between DLC terminal No.4 and body ground.

pic 3

3. Measure voltage between DLC terminals No.5 and No.16.

Is there battery voltage?

YES - Go to step 4.

NO - Repair open in the wire between DLC terminal No.5 and ECM/PCM (E3).

4. Turn the ignition switch ON (II).

pic 4

5. Measure voltage between DLC terminals No.5 and No.7.

Is there 8.5 V or more?

YES - Go to step 10.

NO - Go to step 6.

6. Turn the ignition switch OFF.
7. Disconnect ECM/PCM connector E (31P). Make sure the OBD II scan tool or Honda PGM Tester is disconnected from the DLC.

pic 5
8. Check for continuity between DLC terminal No.7 and body ground.

Is there continuity?

YES - Repair short to ground in the wire between DLC terminal No.7 and the ECM/PCM (E23). After repairing the wire, check the DTC with the OBD II scan tool/Honda PGM Tester and go to the DTC Troubleshooting index. See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions

NO - Go to step 9.

pic 6

9. Check for continuity between DLC terminal No.7 and ECM/PCM terminal E23.

Is there continuity?

YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.

NO - Repair open in the wire between DLC terminal No.7 and the ECM/PCM (E23). After repairing the wire, check the DTC with the OBD II scan tool/Honda PGM Tester and go to the DTC Troubleshooting index. See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions

10. Turn the ignition switch OFF.
11. Disconnect ECM/PCM connector E (31P). Make sure the OBD II scan tool or Honda PGM Tester is disconnected from the DLC.
12. Turn the ignition switch ON (II).

pic 7

13. Measure voltage between DLC terminals No.5 and No.7.

Is there 0 V?

YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck. If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.

NO - Repair short to power in the wire between the DLC terminal No.7 and the ECM/PCM (E23). After repairing the wire, check the DTC with the OBD II scan tool/Honda PGM Tester, and go to the DTC Troubleshooting index. See: A L L Diagnostic Trouble Codes ( DTC ) > Diagnostic Trouble Code Descriptions

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Here are a few links you may find helpful when testing the DLC (data link connector)

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

Let me know.

Joe

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