LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 2016 >> Civic EX >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Anti-Theft Systems >> Security System / Keyless Entry System - Testing & Troubleshooting >> Input Test >> Immobilizer-Keyless Control Unit Input Test (2/4-door)
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Immobilizer-Keyless Control Unit Input Test (2/4-door)

NOTE: 

1. Turn the vehicle to the OFF (LOCK) mode.

2. Disconnect the immobilizer-keyless control unit 7P connector.

GHH411520Courtesy of HONDA, U.S.A., INC.

Inspect the connector and socket terminals to be sure they are all making good contact:

With the connector still disconnected, do the following input tests:

Cavity Wire Terminal name Test condition Test: Desired result Possible cause if desired result is not obtained
2 RED S-NET Jump the SCS line with the HDS, disconnect PCM connector A (50P) Measure the voltage to ground: There should be about 5 V.
  • An open or high resistance in the wire
  • A short to ground in the wire
Check for continuity between the terminal and PCM connector A (50P) terminal No. 40: There should be continuity. An open or high resistance in the wire
Disconnect the 12 volt battery negative terminal Measure the resistance between the terminal and body ground: There should be more than 50 kΩ.
  • Poor ground (G503)
  • An open or high resistance in the ground wire

Reconnect the connector to the immobilizer-keyless control unit, do the following input tests:

NOTE:  After replacing the immobilizer-keyless control unit, and do the immobilizer key registration .

Cavity Wire Terminal name Test condition Test: Desired result Possible cause if desired result is not obtained
7 RED +B BACK UP Under all conditions Measure the voltage to ground: There should be battery voltage.
  • Blown No. A18 (10 A) fuse in the under-hood fuse/relay box
  • An open or high resistance in the wire
6 PUR IG1 MON Vehicle ON mode Measure the voltage to ground: There should be battery voltage.
  • Blown No. B11 (5 A) fuse in the under-dash fuse/relay box
  • An open or high resistance in the wire
1 BRN GND In all power modes Measure the voltage to ground: There should be less than 0.2 V.
  • Poor ground (G503)
  • An open or high resistance in the ground wire
3 LT BLU K LINE Under all conditions Measure the voltage to ground: There should be pulse voltage (digital signal).
  • Faulty control unit on the K LINE
  • Short to ground in the K LINE wire