Immobilizer-Keyless Control Unit Input Test
WARNING: This page is about a different car, the 2013 Acura MDX, 2012 Acura MDX, 2011 Acura MDX, and 2010 Acura MDX. 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 (see COMPONENT LOCATION INDEX ), and precautions and procedures (see PRECAUTIONS AND PROCEDURES ) before doing repairs or servicing.
- Before testing the immobilizer-keyless control unit, troubleshoot the multiplex integrated control unit first, using B-CAN System Diagnosis Test Mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ) and check the No. 19 (20 A) and No. 7 (10 A) fuses in the under-dash fuse/relay box.
- Remove the steering column covers (see COLUMN COVER REMOVAL/INSTALLATION ).
- Disconnect the 7P connector (A) from the immobilizer-keyless control unit (B).
- 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 look 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 Test condition Test: Desired result Possible cause if desired result is not obtained 3 LT GRN (S-NET) Disconnect PCM connector A (49P) and under-dash fuse/relay box connector Q (14P). Check for continuity between terminal No. 3 and PCM connector A (49P) terminal No. 46:
There should be continuity.An open or high resistance in the wire Check for continuity between terminal No. 3 and under-dash fuse/relay box connector Q (14P) terminal No. 9:
There should be continuity.Check for continuity to body ground:
There should be no continuity.A short to ground in the wire 4 LT GRN (B-CAN) Disconnect under-dash fuse/relay box connector N (45P). Check for continuity between terminal No. 4 and under-dash fuse/relay box connector N (45P) terminal No. 28:
There should be continuity.An open or high resistance in the wire Check for continuity to body ground:
There should be no continuity.A short to ground in the wire 5 ORN (K-LINE) Under all conditions Check for continuity between terminal No. 5 and data link connector (16P) terminal No. 7:
There should be continuity.An open or high resistance in the wire Check for continuity to body ground:
There should be no continuity.A short to ground in the 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.
- If all the input tests prove OK, the immobilizer-keyless control unit must be faulty; replace it.
Cavity Wire Test condition Test: Desired result Possible cause if desired result is not obtained 1 WHT (VBU) Under all conditions Measure the voltage to body ground:
There should be battery voltage.- Faulty under-dash fuse/relay box
- Blown No. 4 fuse in the main under-hood fuse box
- Faulty main under-hood fuse box
- An open or high resistance in the wire
2 BRN (IG1) Ignition switch ON (II) Measure the voltage to ground:
There should be battery voltage.- Faulty under-dash fuse/relay box
- An open or high resistance in the wire
7 BRN (LG3) In all ignition switch positions Measure the voltage to ground:
There should be less than 0.2 V.- Poor ground (G101) or an open in the ground wire
- An open or high resistance in the wire
- Faulty PCM
6 PNK (IG KEY SW) Ignition key inserted into the ignition switch Measure the voltage to ground:
There should be less than 0.2 V.- Poor ground (G601) or an open in the ground wire
- Faulty under-dash fuse/relay box
- Faulty ignition key switch
- An open or high resistance in the wire