Immobilizer-Keyless Control Unit Input Test

Turn the ignition switch to LOCK (0).
Disconnect the immobilizer-keyless control unit 7P connector See IMMOBILIZER-KEYLESS CONTROL UNIT REGISTRATION or IMMOBILIZER-KEYLESS CONTROL UNIT REMOVAL AND INSTALLATION .

Fig 1: Immobilizer-Keyless Control Unit 7P Connector Terminal Layout
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Inspect the connector and socket terminals to be sure they are all making good contact:
- If the terminals are bent, loose, or corroded, repair them as necessary, and recheck the system.
- If the terminals are OK, go to step 4.

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

If any test indicates a problem, find and correct the cause, then recheck the system.

If all the input tests prove OK, go to step 5.

Cavity	Wire	Terminal name	Test condition	Test: Desired result	Possible cause if desired result is not obtained
2	YEL	S-NET	Jump the SCS line with the HDS, disconnect PCM connector A (49P) See HOW TO TROUBLESHOOT THE A/T SYSTEM or HOW TO TROUBLESHOOT THE FUEL AND EMISSIONS SYSTEMS	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 (49P) terminal No. 17: There should be continuity.	An open or high resistance in the wire Faulty under-dash fuse/relay box
			Disconnect the battery negative terminal	Measure the resistance between the terminal and body ground: There should be more than 50 kΩ.	Faulty under-dash fuse/relay box Poor ground (G101) An open or high resistance in the ground wire

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

If any test indicates a problem, find and correct the cause, then recheck the system.

NOTE: After replacing the immobilizer-keyless control unit, 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. A29 (10 A) fuse in the under-hood fuse/relay box Faulty under-dash fuse/relay box An open or high resistance in the wire
6	BLU	IG1 FUEL PUMP	Ignition switch ON (II)	Measure the voltage to ground: There should be battery voltage.	Blown No. B4 (15 A) fuse in the under-dash fuse/relay box An open or high resistance in the wire
1	BRN	GND	In all ignition switch positions	Measure the voltage to ground: There should be less than 0.2 V.	Poor ground (G502) 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