Immobilizer-Keyless Control Unit Input Test

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2020 Honda Fit, 2019 Honda Fit, 2018 Honda Fit, 2017 Honda Fit, and 2016 Honda Fit. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

SRS components are located in this area. Review the SRS component locations , and precautions and procedures before performing repairs or servicing.
Before testing, make sure the No. B29 (10 A) fuse in the under-hood fuse/relay box is OK.
Before testing, make sure the No. C32 (15 A) fuse in the under-dash fuse/relay box is OK.

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

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

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

3. 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.

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	BLU	S-NET	Jump the SCS line with the HDS, disconnect PCM connector A (51P)	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 (51P) terminal No. 21: There should be continuity.	Faulty under-dash fuse/relay box 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.	Faulty under-dash fuse/relay box Poor ground (G401) An open or high resistance in the ground wire

5. Reconnect the connector to the immobilizer-keyless control unit, 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, replace the immobilizer-keyless control unit .

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. B29 (10 A) fuse in the under-hood fuse/relay box An open or high resistance in the wire
6	WHT	IG1 FUEL PUMP	Vehicle ON mode.	Measure the voltage to ground: There should be battery voltage.	Blown No. C32 (15 A) fuse in the under-dash fuse/relay box An open or high resistance in the wire
1	BLK	GND	In all power mode s	Measure the voltage to ground: There should be less than 0. 2 V.	Poor ground (G401) 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