2008 Honda Civic will not start with 'green key' on dashboard display. What is the cause?

Create Date: Sept. 17, 2021, 11:42 a.m. (0)

Credit: Honda Immobilizer System Manual

This is to do with the immobilizer system (IMMO) issues .

To make the short long story short, the car IMMO system fails to verify the the key is the legitimate key. So, we have to make sure that the keys used are recognized by IMMO system.

Check the related fuses & relays
Battery voltag ranges 12.45V ~ 15.0V
Reprogram the key to IMMO
Synchronize IMMO and ECM
IMMO and/or ECM offline

How Honda Civic Immobilizer System Works

Fuse#23 in under hood fuse box constantly supplies voltage to the Immobilizer Key-less Control Unit (IKCU). If the voltage is below 11.0V, the problem may happen.

When the key is on ON or START, both IKCU and ECM receives battery voltage through driver's under-dash fuse#2 (PGM-FI). If the authorized key is used then IKCU informs the ECM so that ECM can energize the PGM-FI 2 Main Relay 2 to fuel pump and the car starts. The green immobilizer key symbol will be on for about two seconds and then disappear for normal situation.

Issue environments & Tags

TBC #Engine, #Electrical, #Maintenance, #Emergency

Notes & References

1. https://techinfo.honda.com/rjanisis/pubs/om/AC0606/AC0606O00075A.pdf
2. https://www.civicforums.com/forums/181-8th-9th-generation-civic-2006-2015/362246-car-starts-then-shuts-off-2-seconds.html (Fuse#10 issue)

Tutorial

Battery maintenance basics Car starting problem

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SunJoo Moon , Edit Date: Sept. 18, 2021, 1:07 p.m.